Materials Systems for Extreme Environments (XMat) Annual Report October 2013 ... · 2020. 6....

Materials Systems for Extreme Environments (XMat)

Annual Report October 2013 – September 2014

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XMat Annual Report 2013-2014

Contents 1. Introduction 3 2. Overview of our plan and progress 3 3. Management 6 3.1 Management Board (MB) 6 3.2 Grant Committee (GC) 6 3.3 Audit Committee (GC) 6 3.4 International Advisory Panel (IAP) 6 4. People 7 4.1 Staff 7 4.2 Researchers 10 4.3 Visitors 12 5. Equipment 12 5.1 Ultrasonic Elastic Modulus 12 5.2 Flash Sintering – SPS 13 5.3 High temperature wetting test 13 5.4 Atomic emission spectroscopy 13 5.5 Microwave CVI 14 5.6 Planetary ball mill 14 5.7 Vacuum Hot Press 15 5.8 Other equipment facilities 15 6. Research 15 6.1 PDRA projects 15 6.2 PhD projects 26 7. Impact and Sustainability 27 7.1 Lectures and Visits 28 7.2 Publications 30 7.3 Newsletters 32 7.4 Website 33 7.5 Recent funded proposals associated with XMat 33 7.6 Forthcoming XMat events 34 8. Annex – I 35


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1. Introduction The development of next-generation ceramic and ceramic composite materials is vital for enabling the operation of machinery in extreme conditions, such as severe chemical and radioactive environments. An £4.2M EPSRC Programme Grant was launched in February 2013 to meet this challenge. It is led by the University of Birmingham working with Imperial College London and Queen Mary London. The project is currently using as its foundation cutting edge ceramics and composites developed at these institutions for nuclear fusion, fission, aerospace and other applications where resistance to radiation, oxidation and erosion are needed at very high temperatures. The programme is already beginning to broaden out from this base. The project has already put in place the expertise required to produce a chain of knowledge from prediction and synthesis through to processing, characterisation and application that is enabling the UK to be world leading in ceramic materials for extreme conditions. The project started in February 2013 for a 5-year period and this report covers the second year. 2. Overview of our plan and progress The main objective of this project is to establish in the UK the capability to develop new materials that can operate under increasingly extreme conditions, thus enabling a wide range of new technologies. To achieve the objective, several goals related to synthesis, processing, characterisation and modelling are being achieved, for example:

• Through combined experimental and modelling research we have performed a systematic exploration of complex ternary compounds that will have industrially useful properties (see section 6.2).

• Combining continuum modelling and crystal chemistry concepts to predict intrinsic properties (see section 6.1).

• Synthesising high purity, high melting temperature powders with controlled solid solutions and stoichiometry by a variety of routes and the fabrication of ceramics (see section 6.1).

• Extending the processing window of rapid sintering to higher heating rates, temperatures and pressures and investigating new approaches, including mechano-activated sintering (see section 6.1).

• Developing the ability to produce enhanced fibre-reinforced composites (see sections 6.1 & 6.2).

• Developing state-of-the-art measurement techniques to enable the determination of thermo-physical properties (phase diagrams) and thermo-mechanical properties (creep, fracture strength, yield strength) and evaluate chemical and oxidation resistance.

We are also focused on the impact of our work and highlighting effective dissemination of our research to the academic and industrial communities in a wide range of disciplines and applications (see section 7).

The 3 main phases of the project are: Phase 1 involved setting up the team of academic, administrative, support staff and postdoctoral researchers and the mechanisms of managing and overseeing the project. The 2nd tranche of post-doctoral researchers were recruited during early 2014. As described in Section 3, the research team and Management Board (MB) meets quarterly and an International Advisory Panel, IAP, meets annually (see Section 8).

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A core team has been formed and the project has been publicised via a range of activities including our web site (http://xmat.ac.uk), which is updated regularly with information about the progress of the project and circulating periodic newsletters to the ceramics community. Over the last twelve months we have focused on installing a modest amount of new facilities, including a planetary ball mill, ultrasonic elastic modulus unit, and modifying, using and maintaining our equipment for ultra-high temperature ceramic processing, including a flash sintering – SPS (spark plasma sintering) facility and a microwave – CVI (Chemical Vapour Infiltration) capability (see section 5).

The three universities involved in this project already have well established capabilities with a range of equipment for processing and characterisation. These include a wide range of processing facilities as well as powder characterisation laboratories, room and high temperature mechanical characterisation laboratories and a microstructural characterisation suite (including FIB, SIMS, SEM, TEM, EDS and EBSD) as well as outstanding thermal analysis facilities. This gave the development of the XMat research project a head start by providing a core of capability on which to build.

Phase 2 is focused on developing the research capacity through processing and characterisation of a range of ceramics materials and composites, including MAX phases and ultra-high temperature composites. The research also focuses on hierarchical and predictive modelling capability for simulating experiments that are extremely difficult and expensive.

Phase 3 will continue to keep our profile in the ceramics community high and some of our efforts at gaining publicity are described in section 7. The second newsletter highlighting the progress of the Programme Grant has been circulated and this will be continued periodically.

The proposal received huge support from institutions and industry worldwide (listed below). Air Force Research Laboratory (AFRL), USA Atomic Weapons Establishment (AWE), UK CERAM, UK Culham Centre for Fusion Energy (CCFE), UK Defence Science and Technology Laboratory (DSTL), UK European Space Agency (ESA) FCT Systeme, GmbH (FCT), Germany Institut für Sicherheitstechnologie GmbH (ISTec), Italy Kerneos, France Universite de Limoges (Unilim), France Missouri University of Science and Technology (Missouri S&T), USA Morgan Technical Ceramics (Morgan Plc), UK Air Force Research Laboratory (AFRL), USA NASA, USA National Nuclear Laboratory (NNL), UK National Physical Laboratory (NPL), UK Reaction Engines Ltd., (Reaction Engs), UK Rolls Royce, USA Kennametal, UK MBDA, UK Teledyne, California, USA Tokamak Solutions, Culham, UK TWI, Cambridge, UK Vesuvius, UK

http://xmat.ac.uk/


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Other organisations are most welcome to be part of this project and both the Anglo-French company MBDA and the French company Onera have already joined and are funding research.

LoS* and visitors

FCT

LoS* and visitors

FCT

IAP#IAP#

IndustriesIndustries

PhD studentsPhD students

PDRAs

Jon Binner-PICIs: Bill LeeMike FinnisMike Reece

PDRAs

PI – Principal Investigator CIs – Co Investigators *LoS – Letter of Support #IAP – International Advisory Panel

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3. Management The Management Board (MB), Grant Committee (GC) and International Advisory Panel (IAP) meet regularly to ensure the progress of the project. The main contact of the programme grant is Jon Binner (PI, University of Birmingham), with support from Bill Lee (Imperial College), Mike Finnis (Imperial College) and Mike Reece (Queen Mary University). 3.1 Management Board (MB) The MB is responsible for the direction of the programme and meets quarterly to oversee the running of the project, including issues such as staff appointments and equipment purchases. It is increasingly focused on developing the national and international profile, forging industrial links and financial sustainability. The MB is chaired by Jon Binner and other members are Bill Lee, Mike Finnis, Mike Reece, Mike Angus (NNL), Mike Thomas (Morgan Advanced Materials), Peter Brown (DSTL), Mark Gee (NPL) and Lucy Martin (EPSRC). Amutha Devaraj (XMat Technical Manager) and Keely Austin (XMat Administrator) also attend.

The responsibilities of the Management Board include:

• Monitoring the progress of the overall project. • Overseeing the impact of the project against its strategic objectives. • Monitoring the financial aspects (with input from the Audit Committee). • Providing input to the Principle Investigator and Project Manager on how well the project

is being managed. • Providing a forum for views of sector stakeholders. • Determining the allocation of EPSRC funding (with input from the Grants Committee). • Identifying scientific and technical issues of interest to the project and providing input on

priority areas for future collaborative projects. • Arbitrating if there are problems or individual programmes are not delivering the desired

results. 3.2 Grant Committee (GC) The GC meets quarterly on the same day as the MB. The primary objective is to review all proposals for research using the Programme Grant funding to ensure that the money is spent wisely. The membership of the Grants Committee is chaired by Mike Thomas (Morgan Advanced Materials) and other members are Mark Gee (NPL), Lucy Martin (EPSRC), Jon Binner, Bill Lee, Mike Finnis and Mike Reece. Amutha Devaraj and Keely Austin also attend. 3.3 Audit Committee (AC) The AC meets annually at the time of the annual review meeting. The primary objective is to audit the activities of the Management Board and, more widely, the XMat Programme. The AC is independent of, but reports to the Management Board. Financial data is provided to the AC by the administrative team based at the University of Birmingham and Imperial College. The membership of the Grants Committee is chaired by Pete Brown (DSTL) and other members are Lucy Martin (EPSRC), Jon Binner, Bill Lee, Mike Finnis and Mike Reece. Amutha Devaraj and Keely Austin also attend. 3.4 International Advisory Panel (IAP) The Industrial Advisory Panel meets annually on the occasion of the Annual Meeting. All current members of the IAP were invited to join for 2 years in the first instance, after which the membership will be reviewed at the 2nd Annual Meeting. The responsibilities of the IAP include:


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• Providing independent advice to the Management Board. • Overseeing and advising on the impact of the project against its strategic objectives. • Providing a forum for views of sector stakeholders, both industrial and academic. • Advising the Management Board on suggested allocation of EPSRC funding. • Advising on scientific and technical issues. • Advising on priority areas for future collaborative projects. • Advising the Management Board on emerging developments in the sector. The IAP is chaired by Prof Paolo Colombo (Univ of Padua, Italy) and other members are: Prof Bill Fahrenholtz (Univ of Missouri S&T, USA), Dr David Marshall (Teledyne, USA), Dr Diletta Sciti (ISTEC, Italy), Dr Allan Katz (AFRL, USA) and Prof David Smith (Univ of Limoges, France). Lucy Martin (EPSRC), Jon Binner, Bill Lee, Mike Finnis, Mike Reece, Amutha Devaraj and Keely Austin also attend. 4. People The Programme Grant team includes those funded through the EPSRC award and those associated with the centre but not funded by the award, which include two PhD students. A sixth academic, Prof Bala Vaidhyanathan (Loughborough University), and tenth post-doc, Dr Ji Zou, will join the team in October 2014 and additional PhD students are being pursued. 4.1 Staff

Professor Jon Binner is currently the Professor of Ceramic Science & Engineering and Deputy Head of the Engineering and Physical Sciences College at the University of Birmingham, UK. The focus of his research for over 30 years has been the generation of both the necessary scientific understanding and the required engineering solutions for the development of processing routes for ceramic-based materials that display technical and/or financial advantages over existing processes and that yield new or improved materials. He has been leading ultra-high temperature

composites (UHTC) research since 2008, whilst also pursuing a range of other topics, including developing superior ceramic armours and nanostructured ceramics for a wide range of applications. His esteem is indicated by his being a Fellow of the American Ceramic Society (ACerS), European Ceramic Society (ECerS), the Institute of Nanomaterials (ION) and the Institute of Materials, Minerals and Mining (IOM3). For the latter he is also President and on the Managing Board and Council. He is also a Council Member of the European Ceramic Society (ECerS) and the UK representative on its President’s Executive Council (PEC). Jon is a long-standing member of the EPSRC College. He has received the Holliday Prize (1995), Ivor Jenkins Medal (2007) and Verulam Medal (2011) from the IOM3 and is a Visiting Professor at two Chinese universities.

Professor Bill Lee is professor of ceramics, Director of the Centre for Nuclear Engineering and the Nuclear Energy Centre for Doctoral Training at Imperial College (ICL), His research is focused on obtaining a fundamental understanding of ceramic microstructures, their control by processing and their impact on properties for a broad range of ceramics including refractories, nuclear ceramics, glasses and glass composite materials, clay-based ceramics and UHTCs. He is a fellow of the Royal Academy of Engineering, ACerS (for which he is also an elected member

of the Board of Directors), the IOM3 (for which he also serves on the Prize Awards panel) and the City and Guilds Institute. He is a member of the Board of Directors of the Technology Strategy Board’s Materials Knowledge Transfer Network, the Leverhulme Trust Panel of Advisors, the Scientific and Environmental Advisory Board Tokamak Solutions plc,

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as well as being a technical expert on waste form processing for the International Atomic Energy Agency, Vienna. Prizes include the IOM3 Rosenhain Medal (1999), Pfeil Award (2000), the Wakabayashi Prize of Technical Association of Refractories, Japan (2004) Kingery Award of ACerS, USA (2012) and Hsun Lee award of the Chinese Academy of Sciences (2014). Professor Mike Reece is the Professor of Functional Ceramics, Head of the Functional

Nanomaterials Group at Queen Mary University London (QMUL). His work at QMUL has focused on the understanding the electromechanical properties of ferroelectric, ferroelastic and piezoelectric ceramics. He has set-up the first spark plasma sintering (SPS) furnace in the UK. The focus of his research in this area is to produce new structural and functional materials, including ceramics for extreme environments. This includes nanostructured, textured and metastable materials. A long term objective of his work is commercialise materials prepared by SPS through

knowledge transfer and spin-outs. He is the Director of Nanoforce Technology Ltd, a spin-out company of QMUL, which was funded as part of the DTI Micro- and Nano-technology Network. He is a Royal Society Industry Fellow (2011-2015) and Editor of Advances in Applied Ceramics. He is a visiting professor at the Shanghai Institute of Ceramics and Xi’an Xiaotong University.

Professor Mike Finnis is the professor in the Theory & Simulation of Materials, a joint appointment between the Departments of Materials &Physics at ICL; founder and current Deputy Director of the Thomas Young Centre – London Centre for Theory & Simulation of Materials (www.thomasyoungcentre.org). His most notable scientific contributions are in the modelling of interatomic forces in materials and the use of molecular dynamics and first-principles calculations at the atomic scale to obtain thermodynamic quantities. His book “Interatomic forces in

condensed matter” (OUP 2003), available in paperback and electronically since 2010, is a comprehensive account of the first topic. In 1995 He received the Maxwell Medal and Prize, jointly awarded by the UK Inst. of Physics and the German Physical Soc. He served on the Physics sub-panel of two RAE exercises and is a frequent reviewer for national and overseas funding agencies when theory and simulation of materials is significant, including the Finnish Academy of Sciences and the DFG in Germany. Since 2007 he has been on the Scientific Advisory Board of the Max-Planck-Institut für Eisenforschung in Düsseldorf. He was the 2012 Van Horn Distinguished Lecturer at Case Western University, and is a visiting Professor at Queen’s University Belfast. His publications have attracted >6300 citations.

Dr Luc Vanderperre received both his Masters of Engineering (1993) and Ph.D in Materials Science (1998) from the Catholic University of Leuven in Belgium. He was awarded the 1997 Scientific Prize of the Belgian Ceramic Society for his PhD work. Since then he has worked as a post-doctoral researcher in academia and as a staff member in commercial research (Vito, Belgium). He joined Imperial College in November 2006 from the University of Cambridge. He has long experience in processing as well as in measuring and understanding the

mechanical properties of ceramics and cements. As a member of the Centre for Advanced Structural Ceramics (CASC), he currently works on a range of ceramic as well as cement related projects spanning processing hard ceramics for armour, tailoring mullite for micro-turbine applications, thermal shock of and conversion from cements of refractories, ultra high temperature ceramics for aerospace, re-use of ashes from industrial processes and cements for nuclear waste encapsulation.


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He is a fellow of the Institute of Materials, Minerals and Mining and of the UK higher education academy and a member of the American Ceramic Society for whom he co-organises the annual symposium on ultra-high temperature ceramics.

Prof Bala Vaidhyanathan (also known as Vaidhy) is the Professor of Advanced Materials & Processing and Associate Dean for Enterprise (ADE) of the School of Aeronautical, Automotive, Chemical and Materials Engineering at Loughborough University (LU). Previously he has been a member of the research faculty at the Pennsylvania State University, USA, and a Lead Scientist at General Electric-Global Research Corporation. He is also a fellow of the Higher Education Academy in the UK. He has delivered over 30 Keynote and Invited presentations at

various conferences around the world and is a member of ACerS, ECerS, the Materials Research Society (MRS), IOM3 and is a life member of the Indian Ceramic Society (ICS).

Amutha Devaraj joined the XMat team as Technical Manager in April 2013, she is involved in administrative, financial and managing progress. Prior to this she worked as a Team Leader (Quality and Materials) at Novacem, a carbon negative sustainable material development company. She also has experience working on the development of wide range of materials including ceramics, glass and polymer for industrial applications. She is also engaged with the BioBone project (European FP7) and managing the activities of Centre for Advanced Structural ceramics

(CASC). After her PhD on the development of structural ceramics for refractory applications, she moved to Japan as a research scientist working on different areas of research including processing and development of ceramics, polymer and tribology and surface science studies of ceramic materials. Then she joined Imperial College as a post-doctoral researcher working on sustainable material development from waste resources. She is a life member of the Indian Ceramic Society.

Keely Austin joined the XMat project as an administrator replacing Christina Kokorosko. She has been working as a research administrator for the XMat project since April 2014. She has previously worked for the University of Birmingham in various administration roles within Student Records and Learning. She has also worked in an administrative capacity at BDO Financial and as a coordinator within Learning and Development at Ernst and Young.

Garry Stakalls started as technician for the Centre for Advanced Structural Ceramics (CASC) at ICL in July 2008. Prior to this he worked in the Materials Processing Group within the Department of Materials, where he commissioned and ran large experimental rigs and was involved in the processing of wide range of materials. Garry’s main activities have been to use and train new users on the use of the thermal analysis equipment as well as operating the hot press for sintering and pressing. He also maintains the equipment while liaising with Netzsch for thermal analysis

and FCT for the hot press. The University of Birmingham is currently in the process of recruiting a technician to replace Dr Virtudes Rubio, who is now a researcher on the team. The interviews for the technician are set for the 13th November and so they should be in post by New Year 2015.

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4.2 Researchers Andrew Duff joined the Department of Materials, Imperial College London in August 2013 to work on first-principles modelling of ultra-high temperature ceramics, including ZrC, ZrB2, HfC and HfB2. His research experience extends from first-principles method development (PhD, Bristol University, 2003-2007) to materials modelling, including metals (Delft University of Technology) and semiconductors (Max-Planck-Institut für Eisenforschung) and across a range of methods including density functional theory, quantum Monte-Carlo, kinetic Monte-Carlo and semi-

empirical molecular dynamics.

Anish Paul attained a bachelor’s degree (B.Tech) in Polymer Engineering from Mahatma Gandhi University and a master’s degree (M.Tech) in Polymer Technology from Cochin University of Science and Technology (CUSAT) and a PhD in Nanostructured Ceramics from Loughborough University, UK. After his PhD he worked as a research associate for four years at Loughborough University developing Ultra-High Temperature Ceramic Composites for Hypersonic Applications. Currently he is working on an EPSRC funded project (Xmat) developing a process for the Rapid Fabrication of Fibre Reinforced CMCs by

Microwave CVI. His research interests include: nanostructured ceramics, ultra-high temperature ceramic materials, microwave assisted processing of materials, ultra-high temperature oxidation and characterisation, non-destructive characterisation using micro computed tomography (Micro-CT). Unfortunately, Anish will be leaving XMat to take up a post at Alstom in Switzerland. His replacement is in the process of being recruited with an estimated start date of January 2015).

Denis Horlait joined XMat and the Centre for Nuclear Engineering at the Department of Materials as a post-doctoral research associate in April 2014. His work at Imperial College will focus on MAX phase and their application as protective materials in accidental conditions for nuclear fuel cladding. Prior to this he has done his PhD and a post-doc in Commissariat a l’Energie Atomique centre of Marcoule working respectively on oxide ceramic dissolution and uranium-americium mixed-oxides.

Doni Daniel joined the Department of Materials, Imperial College London in February 2006 and is currently working as a research fellow. After gaining a Ph.D. from Anna University on sol-gel processing of oxide ceramics and composites, he held various positions in Japan and UK. He was an awardee of AIEJ-Monbusho student fellowship and STA post-doctoral fellowship by the Govt of Japan and later he joined the National Institute of Advanced Industrial Science and Technology, Nagoya, Japan as research scientist. He has been awarded Young Asian Scientist

presentation award by the Ceramic Society of Japan in 2002. His research interests include processing of oxide and non-oxide ceramics, environmental barrier coatings for CMCs, diesel particulate filters, joining of materials and nano analytical characterisation. Doni holds 18 patents and published over 80 peer-reviewed papers. He presented over 50 papers in conferences including 6 invited talks. Heacts as a reviewer in many journals including Carbon, Acta Mat., Scripta Mat., Journal of Am. Ceram. Soc., Journal of Euro. Ceram. Soc., and Advances in Applied Ceramic Technology. He is a life member of the Indian Ceramic Society, and has memberships in other bodies such as The American Ceramic Society, IOM3 and UK Defence Ceramics Network.


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Salvatore Grasso joined the School of Material Science and Engineering (SEMS) at Queen Mary University of London in 2011 as an experienced researcher in ceramic processing. Dr Grasso performed his doctoral work (2008-2011) at the University of Tsukuba-NIMS (National Institute for Material Science) Japan. Dr Grasso’s research work is focused on Spark Plasma Sintering (SPS) and other Electric Current Assisted Sintering Techniques. His work aimed to elucidate the unknown mechanisms involved in SPS and identify the critical parameters in SPS processing. He

has published more than 40 papers in peer-reviewed Journals and holds 8 patents. He has delivered 8 invited talks at international conferences.

Sam Humphry-Baker joined the Department of Materials at Imperial College London as a postdoctoral associate in September 2014. His work is focussed on cemented metal-ceramic composites as shielding materials for nuclear reactor applications. His research interest in nuclear materials began at the University of Oxford (MEng, 2005-2009), where he studied radiation-induced segregation in Tungsten alloys, using atomic scale characterisation techniques. Later, at the Massachusetts Institute of Technology (PhD, 2009-2014) he worked on the synthesis and thermal stability of bulk nanostructured thermoelectric

compounds, processed via a powder route.

Virtudes Rubio Diaz completed a BA in Environmental Sciences and MSc in Bioengineering at Miguel Hernandez University of Elche (Spain). She then completed a PhD in Biomaterials in the Biomaterials Unit of Bioengineering Institute at Miguel Hernandez University of Elche, working with calcium phosphate bioceramics and biocements doped with silicon for bone restoration and substitution. Currently she is working at the University of Birmingham as a Research Associate for a project with the Anglo-French company MBDA and the French company Onera, with input

from XMat.

Prabhu Ramanujam joined as a Research Associate in the Department of Metallurgy and Materials at University of Birmingham in July 2014 working on UHTC 3, a project funded by DSTL with input from XMat. He pursued his PhD at Loughborough University (he is currently awaiting his viva) with Jon Binner. He has experience working on different synthesis routes to produce nanoparticles and different sintering routes such as HP, HIP, SPS and flash sintering. He is trained on XRD, TEM, FEGSEM, BET, FT-IR and other analytical techniques to characterise the materials. He is a member

of IOM3, ECerS and ACerS. His research interests include structural and functional ceramic materials, UHTCs, nanoparticle synthesis and materials characterisation. Ji Zou is a postdoctoral researcher who will be joining the XMat team on the 15th October 2014 to work on a project on powder synthesis, green forming and pressureless densification of UHTC-based ceramics and composites. The main theme of the project is to produce ultra-high temperature ceramics using rheology- based green forming routes and flash sintering and to determine the ceramics potential for specific, defence-related applications. He will be based jointly at the Univ of Birmingham and Loughborough Univ. Imperial College is recruiting a postdoc to replace a researcher who recently left the UHTC 3 project, which is funded by DSTL with input from XMat.

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4.3 PhD Students Andrea D’Angio is a PhD student at the University of Birmingham in the School of Metallurgy and Materials working with Jon Binner. Current research interests in XMat programme are focused on the Microwave-Heated Chemical Vapour Infiltration of ultra-high temperature ceramic phases. He has prior experience of working with ISTEC in Italy and is an ACerS PCSA delegate for the 2014-2015. His PhD is funded by the University of Birmingham.

Theresa Davey is a PhD student at Imperial College London. Her research work is on phase stability of materials under extreme conditions. She is an ACerS PCSA delegate for the 2014-2015.

4.4 Visitors We are developing links with institutions that have outstanding capability in structural ceramics research. We have hosted short and long visits from a number of individuals. Some of the visitors have made formal presentations during their visit.

5. Equipment The purchase and installation of large items of equipment under the programme grant, to improve UK capability in fabrication and modelling of structural ceramics, is now almost complete. 5.1 Ultrasonic Elastic Modulus Early May 2013 saw the installation of a new piece of equipment for determining the Young

and shear modulus and Poisson ratio of materials. The measurement principle is based on the relationship between shape, density and stiffness and the natural vibration frequencies of a sample. For example, for determination of the Young modulus, typically a bending vibration mode is excited by hitting a sample supported on the nodes of the vibration with a small projectile in the centre. The resulting vibration is picked up with a microphone and analysis of this signal using the Fourier transformation yields

Date Name Organisation June 2013 Dr Sylvia Johnson NASA Ames Research Centre, USA Sept. 2013 Professor BB Nayak CSIR, India May 2014 Aree Pittayawipas SCG chemicals Dr Yuelei Bai Harbin Institute of Technology, China


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the frequency of the vibration. The software also analyses the decay in amplitude of the vibration with time to determine a value for the damping of the vibration. The model installed comes with a furnace capable of operating to 1750°C in air or inert atmosphere and hardware and software enabling fully automated excitation and measurement, making it possible to investigate the variation of the elastic properties with temperature but also to 13ehavior13ize transitions in the materials 13ehavior from the changes in internal damping of the vibration signal. Some examples from the literature of phenomena giving rise to damping are the glass transition temperature, the hopping of oxygen vacancies bound to dopants in response to stress at low temperature in doped zirconia, and the softening of grain boundary glassy phases in sintered silicon nitride. 5.2 Flash Sintering SPS

Spark Plasma sintering is a rapid sintering technique assisted by pressure and electric field. The technique involves the rapid heating of conductive dies by pulsed DC electric currents. The SPS furnace at QMUL can achieve heating rates of up to 500°C min-1, pressing force of 250 KN and maximum sintering temperature above 2500°C. For example, it is possible to heat up and sinter to high dense many UHTC ceramics within ten minutes. This rapid heating rate combined with high pressure (up to 500 MPa) opens up the possibility of producing new materials with microstructures and properties that cannot be achieved using conventional sintering techniques. SPS can rapidly densify nanopowders to produce nanoceramics. The technique can also be used to produce materials that are difficult to densify (i.e. refractory carbides and borides) using conventional ceramic processing methods. SPS can also make completely new materials, such as multifunctional

ceramic composites, metastable composites containing non-equilibrium phases, materials that combine different phases that would not normally coexist. SPS is also able to produce highly textured, dense ceramics. 5.3 High temperature wetting test

An experimental estimation of reliable equilibrium contact angle (in order to assess the wettability) at very high temperature remains a major challenge, a new advanced technique has been developed at QMUL. This method consists of the in-situ measurement of the contact angle using Spark Plasma Sintering (SPS) up to 2000-2300°C and heating rate is up to 1000°C/min.

5.4 Atomic emission spectroscopy discharge through electrically conductive powder compacts Atomic emission spectroscopy revealed that Spark Plasma Sintering (SPS) under typical conditions (<10 V applied across the sample) does not generate a plasma when the electric current flows across conductive particles (e.g., ZrB2, W). The formation of plasma cannot be

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excluded in the case of other ECAS techniques employing higher voltages. We report the in-situ observation of plasma only in pressureless conditions, in a flowing argon atmosphere and when a voltage of 50 V is applied across a 1 mm thick loose compact of electrically conductive powder. The plasma formation produced surface cleaning as confirmed by the oxygen spectral emission lines, and high localized melting, Tm ≈ 3683 K, as also confirmed by microstructural analysis.

5.5 Microwave - CVI The modification of the MW-CVI system has now been completed. The following list some of the important features of the updated system: • Fully automated operation with

process monitoring & data logging. • Ability to measure preform

temperature from the side and top using 2-colour pyrometers (minimising measurement error due to emissivity variations).

• Fully automated chamber pressure control between 10 and 800 mbar.

• Arc detector to safeguard the system in the event of an arc formation. • Automatic pH monitoring and control system. • Alcohol injection system. • Hydrogen leak detection system. The MW-CVI system is capable of operating at up to 1300°C (limited by the quartz bell jar) under a variety of gas atmospheres. It is currently being used for the deposition of SiC matrices around SiC fibre preforms and will be used within the programme for the deposition of UHTC matrices around UHTC fibres. 5.6 Planetary ball mill

RETSCH’s innovative Planetary Ball Mills meet and exceed all requirements for fast and reproducible grinding down to the nano range. They pulverize and mix soft, medium-hard to extremely hard, brittle and fibrous materials. They are suitable for both dry and wet grinding. Also milling can be carried out in a controlled atmosphere.


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5.7 Vacuum hot press The vacuum hot press from FCT System is up and running and is heavily used. The press will operate at temperatures up to 2400°C for sintering and 2100°C for hot pressing with a maximum force of 250 KN and at atmospheric pressure or under vacuum. The pressed volume is 8 cm diameter and 10 cm tall. The larger diameter of 8 cm allows more samples to be produced from one pressing run. Materials pressed include silicon carbide, tantalum and hafnium carbide, joining of UHTC’s, nacre-like SiC structures and mullite.

5.8 Other equipment facilities All equipment at ICL is available to the UK ceramics community – please contact Amutha Devaraj, [email protected] or Garry Stakalls, [email protected], if you wish to use any of these facilities, see http://www3.imperial.ac.uk/structuralceramics/facilities. The other equipment facilities at the Department of Materials are available at http://www3.imperial.ac.uk/materials/facilities. All equipment at QMUL is available to the UK ceramics community, see http://ceramic.nanoforce.co.uk/ and http://www.sems.qmul.ac.uk/staff/[email protected]. All equipment at UoB is also available to the UK ceramics community, contact [email protected]. 6. Research 6.1 PDRA projects Microwave Assisted Chemical Vapour Infiltration (MW-CVI) of Ultra High Temperature Ceramics (UHTCs) Dr Anish Paul and Prof Jon Binner (UoB)

Microwave assisted chemical vapour infiltration is a process whereby a porous preform is heated by the energy supplied by microwaves. As the gas that thermally decomposes to yield a dense matrix passes through, deposition occurs from the inside-out due to the development of an ‘inverse temperature profile’, allowing the process to occur in days rather than the months required by conventional CVI.

The infiltration process will be carried out using the MW-CVI system at University of Birmingham. The overall objective of the project is to deposit UHTC phases, but preliminary heating trials are being carried out using SiC preforms because of the relative ease of depositing SiC from methyltrichlorosilane and the ability of SiC to absorb microwaves. This will give the necessary experience to progress to UHTC deposition. Initially, porous SiC preforms are being used, these will subsequently be replaced by SiC fibre preforms and then by UHTC systems. In conventional, resistance heated, CVI infiltration is typically carried out at ~1-2 mbar. Preliminary MW heating of preforms at this pressure resulted in the formation of MW plasma; heating trials carried out under an argon atmosphere at different chamber pressures indicated that strong plasma is formed at 25 mbar whereas no plasma formation was observed at 50 mbar or above. A representative time-temperature and time power plot from a typical MW heating trial is shown below.

mailto:[email protected]


http://www3.imperial.ac.uk/structuralceramics/facilities

http://www3.imperial.ac.uk/materials/facilities

http://ceramic.nanoforce.co.uk/

http://www.sems.qmul.ac.uk/staff/[email protected]


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Figure 1: Time-temperature and time-power plot from a representative heating trial. The vertical lines indicate the region where the temperature was regulated by the programmer. FP- forward power, RP – return power. It can be seen that it is possible to heat SiC preforms to 1000oC in ~10 min. at 600W. The MW unit is capable of delivering up to 3 kW. The controller was able to maintain the temperature within the specified values and the auto tuner was able to keep the reflected power to a minimum.

The design and construction of a chlorinator that is required to produce the precursors for UHTC phases are currently underway. The plan is to move to the deposition of UHTC phases once the chlorinator is ready and sufficient experience is achieved with the deposition of SiC. Further Information 1. ‘Reducing chemical vapour infiltration time for ceramic matrix composites’, Timms LA,

Westby W, Prentice C, Jaglin D, Shatwell RA and Binner JGP. J Microscopy 201 [2] 316-323 (2001).

2. ‘Densification mechanisms in SiCf/SiC composites by microwave enhanced chemical vapour infiltration’, Jaglin D., Vaidhyanathan B., Binner J, Prentice C and Shatwell B, Microwave and Radio Frequency Applications, Proceedings of the 3rd World Congress on Microwave and Radio Frequency Applications, pp 231-240, Folz DC, Booske JH, Clark DE and Gerling JF (Eds), American Ceramic Society, USA (2003).

3. ‘Microwave Heated Chemical Vapor Infiltration: Densification Mechanism of SiCf/SiC Composites’, Jaglin D, Binner JGP, Vaidhyanathan B, Prentice C, Shatwell RA and Grant DG. J Am Ceram Soc. 89 [9] 2710-2717 (2006).

4. ‘Microwave heated chemical vapour infiltration of SiC powder impregnated SiC fibre preforms’, Binner JGP, Vaidhyanathan B and Jaglin D. Adv Appl Ceram. 112 [4] 235-241 (2013).

Densification Assisted by Electromagnetic Fields Dr Salvatore Grasso and Prof Mike Reece (QMUL)

At present more than 500 Spark Plasma Sintering (SPS) units are in operation word wide. In recent years, the rapid development of SPS has been driven by the inherent advantages both in terms of processing (i.e. short processing time, high energy saving) and properties of the consolidated materials (fine/nanostructured microstructure). Our research aims to improve thermo-mechanical properties of UHTCs based on borides and carbides through development of advanced SPS processing.


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Figure 2: (a) STEM imaging and EDS of Ta4Hf1C5 samples SPSed at 2450°C. (b) Plot of the relative density and grain size of ZrB2 sample flash sintered for 0-35 seconds. (c) Graded densification of high purity SiC powder due to the Peltier effect occurring during SPS at 2450°C. (d) Electro-migration of carbon inside the ZrB2 in the vicinity of the eutectic point.

The SPS furnace is limited to up to 2050°C and 60 MPa using high grade graphite. We have developed an SPS set up capable of achieving 500 MPa at 1800°C, Figure 1(a). By using this, full densification of zirconium or hafnium diboride samples was achieved at temperatures as low as 1700°C. Figure 2(a) shows the microstructure of boron carbide samples densified up to 97% at a temperature as low as 1600°C. Ongoing work is focused on the development of high pressure sintering of samples large enough (i.e. Ф 2 cm) to allow conventional mechanical testing. The maximum SPS operating temperature of typically 2050°C is not sufficient to densify without sintering aids ultra-refractories carbides and borides. In order to overcome this limitation the SPS set up sketched in Figure 1(b) has been developed. This device has been successfully employed for reactive sintering at 2450°C of TaxHf5-xC5 samples and complete solid state diffusion was obtained as shown in Figure 2 (b).

The continuous effort to develop sintering technique with even shorter sintering time has driven the development of SPS flash sintering technique, which is sketched in Figure 1(c). By using this device it was possible to reach heating rate of the order of 5000°C min-1, thus allowing the near complete densification (i.e. 95%) of ZrB2 samples in only 35 seconds as shown in Figure 2 (b).

To date, the contribution of electromagnetic fields on SPS densification has not been clearly elucidated. Our work attempt to

improve the understanding of electromagnetic field contribution on particulate sintering through combined experimental and FEM modelling analysis. Our Efforts have been focused on Peltier effect, Figure 2(c), and electromigration, Figure 2(d). Further Information 1. Grasso, S., Sakka, Y.Electric field in SPS: Geometry and pulsed current effects (2013)

Journal of the Ceramic Society of Japan, 121 (1414), pp. 524-526. 2. Grasso, S., Poetschke, J., Richter, V., Maizza, G., Sakka, Y., Reece, M.J.Low-

temperature spark plasma sintering of pure nano WC powder (2013) Journal of the American Ceramic Society, 96 (6), pp. 1702-1705.

3. Grasso, S., Sakka, Y., Maizza, G. Electric current activated/assisted sintering (ECAS): A review of patents 1906-2008(2009) Science and Technology of Advanced Materials, 10 (5), pp. 053001

Figure 1: The recent development of SPS technique. Newly developed SPS configurations allows: (a) sintering pressure up to 500 MPa (at 1800°C); (b) sintering temperature up to 2500°C; and (c) the heating rate up to 5000°C min-1.

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Figure 1: Hf2Al4C5 ceramic reactive sintered at 1900°C by HP.

Figure 2 HRTEM image of Hf2Al4C5 ceramic reactive sintered at 1900°C by HP.

Fabrication of ternary carbides in Hf-Al-C system Dr Doni Daniel and Prof Bill Lee (ICL)

Recent progress in theoretical prediction, preparation and characterization of layered ternary transition metal carbides reveals that it is difficult to synthesize single phase ternary carbides in Zr-Al-C and Hf-Al-C systems [1]. Recently, a new family of layered ternary and quaternary compounds with the general formula of (TC)nAl3C2 and (TC)n[Al(Si)]4C3 (where T = Zr or Hf, n = 1, 2, 3. . .) was developed in the Zr-Al(Si)-C and Hf-Al(Si)-C systems [2-6]. The high degree of stiffness retained at elevated temperatures provide Zr-Al(Si)-C compounds with promising applications in high temperature and ultra-high temperature environments [6]. Michalenko et al. [7] and Nowotny et al. [8] have investigated complex carbides in the ternary Hf–Al–C system; two ternary carbides (Hf3Al3C5 and Hf2Al3C4) were discovered and determined to have hexagonal symmetry with the space group P63/mmc. Their crystal structures can be described as Hf–C slabs in an NaCl-type structure intercalated by Al3C2 blocks, which is similar to the structure of the Zr–Al–C system [1-3]. Later, He et al. [6] successfully synthesized a Hf-Al-C composite composed of Hf3Al3C5, Hf2Al4C5 and Hf3Al4C6 by a hot pressing method and investigated the effect of microstructure on their mechanical and thermal properties. Hence the main objectives are to fabricate single-phase ternary carbides in Hf-Al-C and Zr-Al-C systems and characterise them for their crystal structure and other properties.

Single phase Hf2Al4C5 ceramics was fabricated from hafnium (325 mesh), aluminium (325 mesh) and graphite powders obtained from ABCR, Germany by pressure assisted sintering techniques such as hot pressing and spark plasma sintering. The processing conditions, phase analysis and microstructures were explained in previous annual report. Thin-foil specimens for TEM observations were prepared by slicing, mechanical grinding to 20 μm, dimpling down to 10 μm and ion milling at 4.0 kV. TEM observations were conducted using a 200 kV JEOL FX2100 (Tokyo, Japan) which was equipped with an EDS system, and high-angle annular dark field (HAADF) detector in scanning TEM system. Fast Fourier transformation (FFT) was carried out in the Digital Micrograph software package.

A detailed microstructural analysis was carried out by TEM. Figure 1(a) shows bright field (BF) images of Hf2Al4C5 sintered at 1900°C by hot press. Two different types of grains are seen; large grown grains with many striations and small sub-micron size particles. Figure 1 (b) shows an HAADF image of the interface between labelled regions B and D in Figure 1 (a) at a higher magnification. It can be clearly seen that large grains have very fine striations running over them which represent a layered structure. Figure 1 (c) is a BF image from another area. Figure 2 (a) shows a region containing small crystals and enlarged grains. The SAED pattern, Figure 2(b), taken on large grains along the zone axis [110] confirms it as a super layer structure. Figures 2 (c) and (d) show the interfaces of regions between B&C and C&bottom grains, respectively. Both HRTEM images show that the grain boundaries are clean and no trace of liquid is seen.

Figure 3 shows the high resolution TEM image of Hf2Al4C5 ceramics obtained with the incident beam parallel to the [110] direction


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Figure 3 HRTEM, SAED, FFT and atomistic simulation of Hf2Al4C5 –z.a.[110]

and Fig. 3(b) shows the SAED taken along the the zone axis [110] and the diffraction points are indexed. Fig. 3(c) shows the enlarged image of square marked in Fig. 3(a). Fig. 3(d) represents the corresponding FFT altered image and the inset in Fig. 3(d) shows the simulated pattern of Hf2Al4C5 crystal using crystal maker.

The simulated pattern can be nicely super imposed with FFT image. The enlarge image of FFT image can be seen in Fig. 3(e). It is very clear from the FFT image and simulated image that two Hf-C slabs are separated by an Al4C3 layer in Hf2Al4C5. The atomistic model shown in the inset of Fig. 3(e) is

created by crystal maker. The lattice parameter is calculated from the FFT image of Fig. 3(d); a=b=3.082 Å, c=38.30 Å, α=β= 90°, γ=120°.

TEM analysis confirms that single phase Hf2Al4C5 was successfully synthesised by reactive sintering processing using pressure assisted sintering techniques. FFT image clearly shows that two Hf-C slabs are separated by an Al4C3 layer in Hf2Al4C5. References 1. J. Wang and Y. Zhou, “Recent Progress in Theoretical Prediction, Preparation, and

Characterization of Layered Ternary Transition-Metal Carbides”, Annual Review of Materials Research, 39 (2009) 415-443.

2. Y.-C. Zhou, L.-F. He, Z.-J. Lin and J.-Y. Wang, “Synthesis and structure–property relationships of a new family of layered carbides in Zr-Al(Si)-C and Hf-Al(Si)-C systems”, J. Euro, Ceram. Soc., 33 (2013) 2831-2865.

3. Z.J. Lin, M.J. Zhuo, L.F. He, Y.C. Zhou, M.S. Li and J.Y. Wang, “Atomic-scale microstructures of Zr2Al3C4 and Zr3Al3C5 ceramics”, Acta Materialia, 54 (2006) 3843-3851.

4. L. He, Z. Lin, J. Wang, Y. Bao, M. Li and Y. Zhou, “Synthesis and Characterization of Bulk Zr2Al3C4 Ceramic”, J. Am. Ceram. Soc., 90 (2007) 3687-3689.

5. L.F. He, Z.J. Lin, J.Y. Wang, Y.W. Bao and Y.C. Zhou, “Crystal structure and theoretical elastic property of two new ternary ceramics Hf3Al4C6 and Hf2Al4C5”, Scripta Materialia, 58 (2008) 679-682.

6. L.F. He, Y.W. Bao, J.Y. Wang, M.S. Li and Y.C. Zhou, “Microstructure and mechanical and thermal properties of ternary carbides in Hf–Al–C system”, Acta Materialia, 57 (2009) 2765-2774.

7. C.I. Michaenko, Y.B. Kuz'ma, V.E. Popov, V.N. Gurin, A.P. Naetshitaylov, and A.N. Nardov, 4th conference on the crystal chemistry of intermetallic compounds, 1978.

8. H. Nowotny, J.C. Schuster, and P. Rogl, “Structural chemistry of complex carbides and related compounds”, J. Solid State Chem., 44, 126-133 (1982).

9. Y. Zou, Z. Sun, S. Tada, and H. Hashimoto, “Effect of Al addition on low-temperature synthesis of Ti3SiC2 powder”, Journal of Alloys and Compounds, 461 (2008) 579-584.

10. J. Zhu, “Effect of aluminum on the reaction synthesis of ternary carbide Ti3SiC2”, Scripta Materialia, 49 (2003) 693-697.

Finite Temperature Modeling of UHTCs Dr Andrew Duff and Prof Mike Finnis (ICL)

The aims of the theory and simulation components of the project have been adjusted substantially to: i) take advantage of recent developments in finite temperature theoretical methods (c.f. updated milestone 1); ii) develop these methods further, and capitalize on them by publishing first applications in the field of ultra-high temperature ceramics (UHTCs,

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c.f. milestone 5). Also, on a purely administrative level, the dates of the corresponding milestones have been altered to account for the later starting date of the researcher (Andrew Duff, who joined us in August 2013).

Our plan has been to undertake first-principles thermodynamic modelling, taking into account the high-temperature lattice vibrations of the crystal, as well as the role of point defects. For the former, we introduced the important distinction between the quasiharmonic and anharmonic contributions to the free energy. The quasiharmonic contribution treats the lattice vibrations as small, harmonic, excursions of the atoms about their mean positions in the lattice and in general accounts well for the thermal expansion of the crystal (with the lattice spacing calculated by minimizing the free energy). The anharmonic contribution accounts for the remaining contribution of the lattice vibrations, due to third and higher order terms in the energy as a function of atomic displacements, and becomes significant at high temperatures.

There has been some theoretical modelling of the specific heat of ZrC with density functional theory (DFT) and quasiharmonic lattice vibrations [1], however these calculations only go up to 3000K, still well below the melting point of ZrC, and are for perfectly stoichiometric compounds. In addition, anharmonic contributions, which are expected to be significant at the temperatures of interest [2], have yet to be considered.

In our present work, we have taken advantage of the UP-TILD approach [3], which enables fully anharmonic DFT calculations (until recently prohibitively expensive) within a computationally feasible framework.

Since the last annual report, significant progress has been made in the anharmonic calculation of bulk ZrC. This has included a substantial component of method development (milestone 5), carried out in collaboration with researchers at the Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany.

In this method development, we have achieved an order of magnitude increase in the efficiency of the UP-TILD approach by replacing the quasiharmonic reference with an interatomic potential reference.

The proof of concept was first performed for the simple test case of titanium, Figure 1, and we are currently using this method to perform anharmonic calculations on bulk ZrC (milestone 2), which is now nearing completion, with preliminary results presented in Figure 2.

Figure 1: CPU-time against coupling parameter (from 0 to 1, this represents a ‘switching on’ of full anharmonicity) for Ti at 1940K, showing an improvement in efficiency of at least an order of magnitude (the final result requires an integration over λ).

Figure 2: Thermal expansivity of ZrC as calculated in present work within quasiharmonic approximation (red and green curves), and with fully anharmonic UPTILD approach (preliminary result: red cross).


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In spite of the sizeable efficiency gains made by our method development, ZrC has proved to be a particularly challenging material with which to perform these calculations on account of its exceptionally high melting-point. In computational terms, 50 Maus (more than 15 times our group’s full monthly Archer allowance) is necessary to calculate the free-energy for this system. This is a substantially more than is necessary for simpler materials (e.g.: Al, Ti) at lower temperatures. The results are worth the extra resources however: There are few materials for which anharmonicity is expected to have such a sizeable effect, and given the large error bars associated with the experimental measurements at these high temperatures, this is one area where theory can make a significant contribution. In addition, a multitude of anharmonic data can be extracted once the free energy is calculated, with thermal expansivity and heat capacity for example easily calculable by means of a simple post-processing step.

Given the challenges associated with anharmonic calculations of UHTCs, we have refocused our efforts on scoping our further methodological improvements which might be made to enable further efficiency gains (milestone 5). Improvements are expected by further refining the potentials used to drive this method, for example by adding angular contributions to the potentials (through MEAM-type potentials [4]). After making such improvements another possibility might be to build on the approach of Monserrat, Drummond and Needs4 who introduced a perturbation method based on the principle-axes approximation; a method which might benefit from further efficiency gains by employing the potential fitting approach we have developed within the UP-TILD scheme. Once completed, we intend to capitalize on these methodological improvements by using them to calculate for the first time the free energy of HfC

Improving the phase diagram of ZrC by means of a CALPHAD reassessment (to be performed by Theresa Davey) including both new experimental data and also high-temperature ab-initio data, has been one of the main aims of the theory and simulation part of the project. Finite temperature vacancy formation energies will be calculated in the coming year (milestone 1; adjusted to include the effect of temperature) for this purpose.

The major revised plan is:

*Completed References 1. Iikubo, S., Ohtani, H. &Hasebe, M. “First-Principles Calculations of the Specific Heats of

Cubic Carbides and Nitrides”. Materials Transactions 51, 574-577 (2010). 2. Lawson, A. C., Butt, D. P., Richardson, J. W., Li, J. “Thermal expansion and atomic

vibrations of zirconium carbide to 1600K”. Philosophical Magazine 87, 2507-2519. 3. Modelling Simul. Mater. Sci. Eng. 19, 015003 (2011), M. I. Baskes. 4. B. Monserrat, N. D. Drummond, and R. J. Needs., Phys. Rev. B 87, 144302 (2013).

Month: 1-6 7-12 13-18 19-24 Quasiharmonic ZrC, HfC bulk

(milestone 2) * ZrB2, HfB2 bulk * ZrC defects

(milestone 1)

Anharmonic ZrC bulk (milestone 2)

HfC bulk (milestone 5)

Method Development

Potential-driven UP-TILD implemented (milestone 5) *

Tested first on Ti and then on ZrC – orders of magnitude increase in speed (milestone 5) *

Explore other possibilities for improvements (milestone 5)

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Development of MAX Phases for Nuclear Environments Dr Denis Horlait and Prof Bill Lee (ICL)

Fukushimas accidents have recently tragically exposed the fragility of the nuclear fuel cladding (Zr-based alloys) in the case of severe loss of active cooling in the nuclear reactor. Following these events, research on solutions to avoid Fukushima scenario to happen again has been intensified.

Ternary layered carbides [1,2], a class of materials that is largely investigated in XMat (milestones 6, 15 and 16) has been identified as promising candidates to either protect or replace the Zr-based cladding, but also to be possibly used in the harsher environments of the future generation of nuclear reactors. Some of them are called MAX phases if their chemical formula is Mn+1AXn where n is an integer, M is an early transition metal, A is an element of groups 13 to 16 and X is C or N (but almost only carbides would be here considered). They are characterized by their singular structure made by the stacking of MX and A layers. Other non-MAX phases carbides composed of an early transition metal M and of an element of groups 13 to 16 (chiefly Al) exist and for the most, they share a similar layered structure but this time made of MX and Al3C2 or Al4C3 layers [1].

First work of Dr Denis Horlait who joined Imperial and XMat project in April 2014 has been to select relevant ternary layered carbides for the above-described nuclear applications. Main requirements to protect or replace Zr-based cladding materials are the following:

• Protective against steam and air oxidation at a temperature as high as reasonably achievable

• Over failure conditions, no massive production of explosive gases (e.g. H2) • To retain sufficient mechanical properties to keep the fuel confined at temperature /

pressure as high as reasonably possible • Good thermal shock resistance • Fulfil the requirements already achieved by current Zr-based alloys:

o Reasonable neutron transparency o High melting / decomposition temperature o Non deleterious thermal mismatch with fuel o Chemically inactive with the coolant/moderator and with the fuels elements including

fissions products, and diffusion-proof. • From literature on MAX phases and other ternary layered carbides [1,2], many of the

reported compounds could be disregarded, mainly from the neutron transparency requirement and the need for high-temperature steam and air oxidation resistance. Indeed, only Al, Si and/or Cr-based compounds show good resistance to these stresses through the formation of an oxide passivation outer layer during the first stages of the ternary carbide oxidation.

• Based on these considerations, Ti2AlC, Cr2AlC, Ti3SiC2 and Zr-Al-C compounds are the only ternary layered carbides that worth looking into and that are currently investigated through XMat:

• Ti2AlC is known has the best MAX phase for high-temperature oxidizing environment, however the development and the experimental performance of its oxide scale (notably through its adherence) is highly dependent on its first oxidizing treatment. Work is planned to develop a pre-treatment to get an optimized and performant Al2O3 close on the surface of commercial Ti2AlC.

• Cr2AlC has an oxidation resistance very close to that of Ti2AlC. So far there is very little but encouraging work done on the oxidation resistance of (Cr,Ti)2AlC compounds. Only Lee et al. [3] reported the synthesis and oxidation resistance of the (Cr0.95Ti0.05)2AlC solid solution and found different behaviours compared to the end-members. To continue investigating on this system, compositions with Ti/(Ti+Cr) ratio of 5, 25, 50, 75 and 95%


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have been synthesized and sintered using Imperial and Queen Mary facilities. The 5 and 95% compounds are found to be single-phased MAX phases, while the other are polyphasic, strongly suggesting the non-existence of a continuous solid solution for this system. Higher temperature of synthesis will soon be tried while the 5 and 95% compounds will be tested in high-temperature oxidizing conditions.

• Ti3SiC2 has very interesting mechanical properties but its industrial application is often limited by its poor oxidation resistance due to the formation of both SiO2 and TiO2, the latter being permeable to further oxidation. On the other hand, it has been reported the contact of Ti3SiC2 with acid solution could lead to the selective formation of a SiO2 outer layer that can possibly be a good precursor for the development of an efficient passivation layer. Currently, commercial Ti3SiC2 compounds are thus being leached under various temperatures by HCl or HNO3 solutions to try develop such outer layer.

• Zr2AlC has never been reported in literature, but if existing would possibly have very interesting properties for the targeted application, because it is a “211” MAX phase (better oxidation performance due to the relative higher concentration of the “A” element), it is based on Zr (main constituent of nuclear cladding and one of the highest neutron transparency) and on Al, who forms the presumably best passivating oxidation layer, Al2O3. Synthesis attempts are currently carried and are, up to now, unsuccessful, even when partially substituting Zr by Cr. If further attempts are still unsuccessful, work would be shifted on other Zr-Al-C layered compounds (Zr2Al3C4, Zr3Al3C5) and treatments to strengthen their oxidation resistance.

References 1. Wang J. & Zhou Y., Recent Progress in Theoretical Prediction, Preparation, and

Characterization of Layered Ternary 2. Transition-Metal Carbides, Annu. Rev. Mater. Sci. (2009) 39, 415. 3. Barsoum, M.W., Properties of Machinable Ternary Carbides and Nitrides, Wiley-VCH,

Weinheim, Germany, 2013. 4. Lee D.B., Nguyen T.D. & Park S.W., J. Nanosci. & Nanotech. (2010) 10, 319. Irradiation & Thermal Damage Of Cermets In Hard Radiation Environments Dr Sam Humphry-Baker and Prof. Bill Lee, (ICL)

The lack of candidate shielding materials for fusion reactors presents a major challenge to their development [1]. Materials will experience extreme conditions: high heat fluxes, erosion and thermal shock from the plasma, and bombardment by high-energy neutrons. Ceramics based on carbide/nitride/boride compounds and containing a metallic binder (cermets), are promising because of their inherent resistance to thermal shock, oxidation, and sputtering and enhanced neutron absorption properties relative to other candidate materials (e.g. W). An improved understanding of the radiation response of these composites is therefore needed.

Cermets have been studied extensively [2], due to their outstanding properties as abrasive materials. However, little is known about their response in reactor environments. In particular, the response under neutron irradiation, oxidation, and thermal shock must be evaluated and compared to state-of-the-art candidate materials. Secondly, unique material chemistries are needed to assure safety for reactor use; binder metals are restricted to low activation elements, preventing traditional binders such as Co and Ni [1] from being used, with Fe & Cr as potential alternatives. A systematic investigation of various compositions and microstructures is therefore required.

The over-arching goal of the project is to understand structural degradation of novel cermet microstructures under hard radiation environments, and with that develop higher performance materials. To achieve this objective, several goals related to: (1) radiation

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Figure 1: Overview of research concept [3,4].

response, (2) oxidation resistance, (3) thermophysical characterization and (4) thermodynamic modelling, are outlined.

Radiation induced mechanical property degradation tends to limit operation lifetime, therefore detailed characterization of this – including the corresponding microstructural evolution – is needed. This will allow prediction of component lifetime and inform the development strategy for improved materials. At first, small area neutron irradiations will be employed,

which will allow nanoindentation testing as well as microstructural observation via transmission electron microscopy.

Oxidation resistance is required in the case of a loss-of-coolant accident. Cermets have the advantage over traditional shielding materials, e.g. W, in their inherent resistance in this regard, however, a quantitative comparison of oxidation kinetics is a necessary starting point. With baseline data in place, more advanced materials can be explored, such as the possibility of self-passivating additions blended into the surface. A powder processing route will allow various chemistries to be explored. This study can be achieved using the high temperature thermogravimetric analyser/scanning calorimeter within the CASC thermal analysis suite.

Cermets have a high surface heat capacity, due to their high thermal conductivity, low thermal expansivity, and high tensile strength. This renders them highly resistant to thermal shock. However, an understanding of the effect of microstructure and composite chemistry on these properties is still missing. Thermal expansivity will be characterized using dilatometry, thermal expansivity using laser flash techniques, and mechanical strength via microindentation at Imperial College. Direct measurement of thermal shock resistance may require collaboration with Birmingham University, where facilities are available.

Finally, to be able to predict thermal stability of these cermets, their phase diagrams must be established. This understanding will allow development of chemistries for optimised stability, and provide maximum temperature limits for their operation. The CALPHAD method (CALculation of PHAse Diagrams) will be used, and implemented using Thermocalc. This part of the project will involve collaboration from Mike Finnis and Teresa Davey. References 1. E.E. Bloom, J. Nucl. Mater. 258–263, Part 1, 7 (1998). 2. G.S. Upadhyaya, in Cem. Tungsten Carbides, edited by G.S. Upadhyaya (William

Andrew Publishing, Westwood, NJ, 1998), pp. viii–x. 3. M.F. Ashby, 1856176630, and 978-1856176637, Materials Selection in Mechanical

Design, Fourth Edition, 4 edition (Butterworth-Heinemann, 2010). 4. Sandvik Hard Materials. <http://www.hardmaterials.sandvik.com/> MBDA programme: Ultra High Temperature Composites Materials & Improvement of Onera low cost CMC Dr Virtudes Rubio and Prof Jon Binner, (UoB)

The primary aim of this work is to evaluate the high temperature performance, durability and mechanical properties of the Ultra-High Temperature Ceramic (UHTC) composites originally developed by Loughborough University under contract from DSTL with a view to exploiting them for missile applications.


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A range of samples have been produced, including: 12 shear, 12 compression, 12 flexural and 36 tensile. The standard 2.5D carbon fibre preforms from Surface Transforms were impregnated by vacuum impregnation with a HfB2 powder / phenolic slurry following the standard procedure. After six vacuum impregnation cycles and two pyrolysis (each performed after three impregnations), the porosity in the samples was closed by infiltrating with carbon using CVI performed by Surface Transforms. Since the tensile samples were much larger than the others, a larger vacuum chamber (800 mm ø) needed to be constructed; this will be of benefit for other related research programmes that also need large samples, e.g. UHTC3 funded by DSTL.

Shear, compression and flexural strength will be measured at room temperature and the tensile strength at room temperature, 500°C and 1000°C. Thermal testing will be undertaken using an oxyacetylene torch test at up to ~2700°C.

An additional project involves seeing if a composite developed by Onera in France, which has a temperature limitation of 800ºC, can be enhanced via the addition of HfB2 powder. The goal is to be able to use the material at up to 1400ºC without incurring a large increase in production costs. However, vacuum impregnations using standard slurries based on HfB2, ZrB2, and ZrB2+SiC yielded poor results, with non-uniform impregnation of the samples.

Rheological studies performed using different amounts of UHTC powders and solvent yielded more success. The next step will be to test the samples by oxyacetylene torch to determine the high temperature performance. Processing of UHTC composites for hypersonic applications - UHTC 3 Dr Xiaoxue Zhang* and Dr Luc Vandeperre (ICL), Dr Prabhu Ramanujam and Prof Jon Binner (UoB)

Zirconium diboride (ZrB2) and hafnium diboride (HfB2) belong to a family of materials known as ultra-high temperature ceramics (UHTCs), which have melting temperatures of over 3000ºC. ZrB2 and HfB2 also offer high thermal and electrical conductivities, great thermal shock resistance, high strength, high hardness and good chemical stability, making them particularly promising candidate materials for the sharp leading edges in hypersonic aerospace vehicles.

Due to their strong covalent bonding and low self-diffusion, high temperature and external pressure are typically required to obtain dense structure using for example hot pressing and spark plasma sintering (SPS). Pressureless sintering has the advantage of fabricating large near net shape components. Therefore pressureless sintering of ZrB2 and HfB2 has attracted good attention in recent years to discover the potential of processing dense ZrB2 and HfB2 without use of external pressure.

It is generally accepted that ZrB2 and HfB2 are very difficult to be sintered to full density without pressure due to their poor intrinsic sinterability. One effective way of improving densification is to use nanosized starting powder, however, these offer suffer from agglomeration. Very high shear milling such as attrition milling can also be applied to reduce the particle size of commercial available powders, however, contamination is readily introduced from the milling process and the particle size can only be reduced down to sub-micron levels. Another approach to enhance densification in pressureless sintering is to use sintering additives, though this approach may compromise the properties at high temperatures. Hence it is important to minimize the amount of additives and carefully choose those that will not harm the properties at high temperatures. Therefore at ICL the study is aimed at investigating the use of carbon as a sintering additive to densify ZrB2 and HfB2 via pressureless sintering.

At UoB, the main aim of the project is to investigate the potential for scaling up the manufacture of hybrid UHTCs for hypersonic applications. An existing process route developed via earlier funding from DSTL will be investigated further to determine the depth and uniformity of impregnation as a function of different sample dimensions. In particular,

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large hybrid UHTC panels, both flat and curved, will be produced using HfB2 slurries to evaluate the high temperature mechanical properties and the ablation resistance will be assessed via oxyacetylene torch and arc jet testing. After testing, the samples will be further analysed using XRD and FEGSEM/EDX to gain the insights into the phase transformations occurring due to the extreme environments. Another objective is to develop a suitable route for joining monolithic with the hybrid UHTC composites and to investigate the need for superior surface finishes. A particular feature of this programme is also to increase the levels of interaction with other researchers working on UHTCs around the world. *Dr Zhang has now left the XMat programme and is due to be replaced as soon as possible. Further Information: 1. J. Zou, G. J. Zhang, Y. M. Kan and T. Ohji, Pressureless sintering mechanisms and

mechanical properties of hafnium diboride ceramics with pre-sintering heat treatment, Scripta Mater 62 (2010) 159 - 162

2. W. G. Fahrenholtz and G. E. Hilmas, Refractory diborides of zirconium and hafnium, J. Am. Ceram. Soc. 90 (2007) 1347 – 1364

3. Chamberlain, W. G. Fahrenholtz and G. E. Hilmas, Pressureless sintering of zirconium diboride, J. Am. Ceram. Soc. 89 (2006) 450 - 456

4. W. G. Fahrenholtz, G. E. Hilmas, S. C. Zhang and S. Zhu, Pressurelss sintering of zirconium diboride: particle size and additive effects, J. Am. Ceram. Soc. 91 (2008) 1398 - 1404

5. D. W. Ni, J. X. Liu and G. J. Zhang, Pressureless sintering of HfB2-SiC ceramics doped with WC, J. Euro. Ceram. Soc. 32 (2012) 3627 – 3635

6.3 PhD projects Phase Stability of Materials under Extreme Conditions Theresa Davey and Prof Mike Finnis

The main aim of this research is to examine the phase stability of certain materials, particularly under extreme conditions such as ultra-high temperatures and irradiation. This understanding will enable materials systems to be designed with precise knowledge of the material behaviour and the optimum composition for each application.

This project uses the CALPHAD method to combine experimental and simulated data with theoretical thermodynamic descriptions in order to provide a consistent model for each material. Data found both in the literature and measured by others in the XMat project is used. The materials assessed are chosen by their suitability and availability of applicable data.

This project will examine all sub-systems within the quaternary boron-carbon-hafnium-zirconium, and the ternaries carbon-hafnium-tantalum, titanium-aluminium-carbon, and hafnium-aluminium-carbon, the latter two of which show the presence of MAX phases. Most of these materials are ultra-high temperature refractory ceramics, and are suitable for extreme conditions applications as they maintain their strength under high temperature. Currently the phase stability of such materials is not well understood, and so improvement of the thermodynamic descriptions of these compounds represent a significant step towards the goal of having an adequate understanding of such materials to design and manufacture materials systems for extreme conditions applications.

In this project, a critical review of each system will be undertaken, examining all previous CALPHAD assessments, relevant models, and experimental data in the literature and from others working in XMat. From this, key areas in need of improvement will be identified, before a review will be made of each system. Using the CALPHAD approach, all experimental and simulated data is fitted to a thermodynamic model using ThermoCalc software.


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Currently, the quaternary system boron-carbon-hafnium-zirconium is the main focus, and critical reviews on each sub-system are underway. Following a CALPHAD assessment of this system, each of the other ternary systems will be examined based on the availability of experimental data and interest within the XMat project. Microwave Assisted Chemical Vapour Infiltration (MW-CVI) of SiCfibres/SiC composites Andrea D’Angio’ and Prof Jon Binner, (UoB)

Carbide fibre-matrix composites are excellent candidates for applications in highly demanding environments because of their excellent thermo-mechanical properties at high temperature. Chemical vapour infiltration (CVI) of porous bodies is an attractive technique for producing these materials at relatively low temperatures and pressures and it is a near-net shape process. It consists of the thermal decomposition of a gas phase to yield a solid matrix within a heated porous preform. However, the long processing time (months) and high residual porosity (10-20%) limit this route. This is due to the deposition that occurs preferentially near the outer surface where the concentration of reactants is higher. In this condition, the formation of a “crust” occurs and seals the porosity at the surface of the preform. Therefore, the infiltration has to be stopped and it is necessary reopen the porosity through machining.

To overcome this limit, the heating of the preform is performed using microwaves and as a result of the nature of the volumetric heating coupled with surface losses an inverse temperature profile is generated, i.e. the centre of the body becomes hotter than the surface. As a result, the deposition starts preferentially in the centre and moves toward the surface of the preform. Premature pore closure due to crusting is avoided and the densification can occur as little as in 24 -72 hours. Note, however, that MCVI can be used only if the materials absorb microwaves. A few preliminary heating trials have been carried out using porous SiC foams. The trials have confirmed that the sample can be heated up to 1273 K both at atmospheric pressure and in vacuum. Below 25 mbar plasma formation has been observed. Future work will focus on the heating up to 1273 K of a Hi-Nicalon™ SiC fibrous two-dimensional preforms. Then, the fibres will be infiltrated with a mixture of methyltrichlorosilane (MTS) and hydrogen H2 for the fabrication of SiCfibres/SiC composites. The effects of partial pressure, temperature and MTS/ H2 molar ratio will be investigated. Microstructure and porosity will be evaluated by SEM and micro-CT. Further Information 1. Microwave Heated Chemical Vapor Infiltration: Densification Mechanism of SiCf/SiC

Composites’, Jaglin D, Binner JGP, Vaidhyanathan B, Prentice C, Shatwell RA and Grant DG. J Am Ceram Soc. 89 [9] 2710-2717 (2006).

2. Golecki, I., Rapid vapor-phase densification of refractory composites. Materials Science & Engineering R-Reports, 1997. 20(2): p. 37-124.

3. Microwave heated chemical vapour infiltration of SiC powder impregnated SiC fibre preforms’, Binner JGP, Vaidhyanathan B and Jaglin D. Adv Appl Ceram. 112 [4] 235-241 (2013).

7. Impact and Sustainability With the appointment of academics, research staff and then support staff, publicity has focused on staff presenting at and taking part in discussions at conferences and on overseas visits. The website continues to make information available including upcoming events.

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7.1 Lectures and Visits

Jon Binner

• Visited AFRL, Dayton, OH, USA: Fri 25th Jan 2013 – presentation given on XMat • Invited Lecture High-Temperature Strength Measurements of Cf-HfB2 UHTC

Composites, Paul A, Binner J, Vaidhyanthan B, Heaton A and Brown P. 37th International Conference and Expo on Advanced Ceramics and Composites, Daytona Beach, FL, USA, 27th Jan to 1st Feb 2013.

• Nano HfB2 Powders, Mini-composites and Impregnated Carbon Fibre Preforms, Venugopal S, Paul A, Zheng P, Vaidhyanathan B, Binner J, Brown P. 37th International Conference and Expo on Advanced Ceramics and Composites, Daytona Beach, FL, USA, 27th Jan to 1st Feb 2013.

• Synthesis of HfB2 Powders for Aerospace Applications, Zheng P, Venugopal S, Paul A, Binner J and Vaidhyanathan B. 37th International Conference and Expo on Advanced Ceramics and Composites, Daytona Beach, FL, USA, 27th Jan to 1st Feb 2013.

• Visit to MBDA, Stevenage, UK: Tues 26th Feb 2013 – presentation given on XMat; led to a contract to work with us on the programme.

• Keynote Lecture High-Temperature Strength Measurements and Arc-Jet Testing of Cf-HfB2 UHTC Composites, Binner JGP, Paul A, Venugopal S, Vaidhyanathan B, Brown P and Heaton A. 13th International Conference of the European Ceramic Society, Limoges, France, June 2013.

• Visited Alstom, Baden, Switzerland: Fri 13th Sept 2013 – presentation given on XMat • Invited Lecture Processing and Properties of UHTC Composites, Binner JGP. 13th

International Ceramics Congress, Montecatini Terme, Tuscany, Italy, June 2014. • Keynote Lecture Processing and Characterisation of Advanced Ceramics for

Demanding Applications, Binner JGP, Keynote paper, 11th Conference on Solid State Chemistry, Trenčianske Teplice, Slovakia, July 2014.

• Kenote Lecture UHTC Composites: From powder synthesis to arc-jet testing, Binner J, Paul A, Vaidhyanathan B, Venugopal S, Zheng P and Brown P, 5th International Congress on Ceramics, Beijing, China, August 2014.

• Plenary Lecture Processing and Characterisation of Advanced Ceramics for Demanding Applications, Binner J, PSA 2014 Conference and Exhibition, Manchester, UK, September 2014.

Doni Daniel

• Development of ultra-high temperature ceramics (UHTCs) for hypersonic applications AMPC 2013, D.D. Jayaseelan, P. Brown and W.E. Lee, Invited Lecture, Chennai, India, Feb. 6-8, 2013.

• Guest Lecture Materials for extreme environments, D.D. Jayaseelan, The Indian Ceramic Society – Chennai Chapter, India, Feb. 5, 2013.

• Materials for extreme environments, D.D. Jayaseelan and W.E. Lee, CASC Industrial Day, May 25, 2013.

• Process development and microstructural characterization of (Ta,Hf)C ultra-high temperature ceramics, O. Cedillos, D.D. Jayaseelan and W.E. Lee, ECERS XIII, Limoges, France, June 23-27, 2013.

• Invited lecture Joining – Ultra high temperature ceramics, AWE Joining Symposium, D.D. Jayaseelan, L. Vandeperre, P. Brown and W.E. Lee, Surrey, UK, July 24, 2013.

• Invited Lecture Development of multilayered UHTCs for thermal protection systems, D.D. Jayaseelan, P. Brown, C. Allen and W.E. Lee, HT-CMC8, Xi’an, China, Sept. 22-26, 2013.

• Visited the US Air Force Research Lab (AFRL), Dayton, Doni Daniel and Bill Lee, and gave presentations on UHTC research at Imperial College and Development of multilayered UHTC composites, Ohio, 6-7, June 2013.


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• XMAT project on Zr-Al-C and water vapour corrosion resistance at high temperature in CARAT 2nd conference call on MAX phase collaboration at Dalton Nuclear Institute, D.D. Jayaseelan, The University of Manchester, June 16, 2014.

• Workshop on Review of the NHSC Program and Future of High Temperature Structural Ceramics, D.D. Jayaseelan, Colorado, US, July 28-31 2014

Andrew Duff

• Visited the Max Planck Institut fuer Eisenforschung to collaborate with them on calculations of high-temperature free energy, Aug 23 - Sep 1 2013.

• Bringing Modelling to UHTCs, Andrew Ian Duff, Theresa Davies, Bill Lee, Mike Finnis, Invited talk at CIMTEC 2014.

Mike Finnis

• Participated in the Unary Workshop at Schloss Ringberg, 24-29 March 2013, one of a CALPHAD series, organised this time by Tilman Hickel (MPI Düsseldorf) and Suzana Fries (ICAMS, Bochum).

• Participated in CCP9 Conference, Clare College Cambridge, 1-2 April 2014. • Participated in UKCP Meeting, Kings College London, 8 April, 2014. • Invited Lecture ICMR Summer Workshop on Ab-initio description of charged systems

and solid/liquid interfaces for semiconductors and electrochemistry, Santa Barbara, 6-11 July 2014.

• Invited visitor at ICAMS (Interdisciplinary Centre for Advanced Materials Simulation), Ruhr-Universität Bochum, August – October 2014, developing contacts here, and with other visitors from the MPIE in Düsseldorf, The Centre for Advanced Ceramics (TU Hamburg), the Materials Department in UCSB.

Salvatore Grasso

• Invited Lecture Electric Current Activated/Assisted Sintering (ECAS): 20 years impact on science and technology in 10th Pacific Rim Conference on Ceramic and Glass Technology (PACRIM 10) in Coronado USA, June 2013.

• Visited Loughborough University to see the processing laboratories (powder synthesis and microwave sintering) and characterization facilities (TEM, STEM). The purpose of the visit was to develop joint efforts between QMUL, ICL and LU in order to achieve a more complete understanding of Flash Sintering technique, July 2013.

• Visited National Institute for Material Science NIMS, Tsukuba Japan, The purpose of the visit was to develop further the existing the collaboration between NIMS and QMUL Salvatore Grasso, Mike Reece, July 2013.

Bill Lee

• Fabrication, Microstructural Characterisation, Oxidation and Laser Testing of Ultra High Temperature Ceramics, Materials Science & Technology Conference, Pittsburgh, Pennsylvania, USA, 10 October 2012.

• Plenary Lecture Fabrication, Microstructural Characterisation, Oxidation and Laser Testing of Ultra High Temperature Non-oxide Ceramics, 6th Intl. Conf. on Advanced Materials and Nanotechnology (AMN6), Auckland, New Zealand, 12 Feb 2013.

• Fabrication, Microstructural Characterisation, Oxidation and Laser Testing of Ultra High Temperature Non-oxide Ceramics, Industrial Research Ltd., Wellington, New Zealand 18 Feb 2013.

• Working with DSTL: The Good, The Bad and The Summary, DSTL National PhD Scheme Conference, Kassam Stadium, Oxford, 27 Feb 2013.

• Fabrication, Microstructural Characterisation, Oxidation and Laser Testing of Ultra High Temperature Ceramics (UHTCs), Dept. of Materials, Oxford University 9 May 2013.

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• Current and Future Ultra-high Temperature Ceramics Research at Imperial College, Materials Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio, USA 7 June 2013.

• Imperial’s Fuel Cycle Research, IChemE Nuclear Research Seminar, Magdalene College, Cambridge, Sept. 24th. 2013.

• The UKs Radioactive Waste Management Programme, Materials Science and Technology, Montreal, Canada, Oct 28th. 2013

• Materials research for Inertial Fusion Energy and Magnetic Confinement Fusion, UK Inertial Fusion Energy Network Kick-off Meeting, Royal Society, London, Nov 26th. 2013

• Understanding Wasteforms from Thermal Treatment Methods, Thermal Treatment of Radioactive Wastes meeting, Risley, Dec 12th.2013

• UK Trade and Investment UK-China Civil Nuclear Mission – Industry Days, London, Nuclear R&D in UK Universities, Jan 24th 2014.

• EPSRC DISTINCTIVE (Decommissioning, Immobilisation and Storage Solutions for Nuclear Waste Inventories) Consortium Kick-off Meeting, Leeds, Work Package on UK Legacy Ponds and Silos Wastes April 29th 2014.

• Current US/UK Nuclear R&D Collaborations, US/UK Technical Experts Workshop, Bilateral Civil Nuclear Energy R&D Cooperation, Institute of Mechanical Engineering, London, May 13th 2014.

• Materials Needs in the UK’s Nuclear Programme, The Armourers and Brasiers Cambridge Forum, Gordon Seminar, June 17th. 2014

• Microstructural Characterisation, Oxidation and Laser Testing of Ultra High temperature Ceramics, China University of Geosciences, Beijing, China, Fabrication, July 14th. 2014

• Fabrication, Microstructural Characterisation, Oxidation and Laser Testing of Ultra High temperature Ceramics, Beihang University, Beijing University of Aeronautics and Astronautics, Beijing, China, July 16th 2014.

• Lee Hsun Award Lecture Structural Ceramics for Extreme Environments, Institute of Metals Research, Chinese Academy of Sciences, Shenyang, China, July 17th.

Mike Reece

• Visited Shanghai Institute of Ceramics, The purpose of the visit was to meet Prof. Guo-Jun Zhang and develop collaboration on development of textured ZrB2, HfB2 ceramics, M. Reece, April 2013.

• Visited Prof D.K. Kim group, KAIST, South Korea, to discuss common interests in UHTC, M Reece, August, 2013.

• Visited NNL, The purpose of the visit was to establish research collaboration between NNL and QMUL. NNL is planning to install a SPS machine for processing nuclear fuel pellets, Mike Reece and Salvatore Grasso, 9th December 2013.

• Visited IFAM in Germany (Dresden). The purpose of the visit was to get and update on the SPS research trends in Germany. On April 11 they visit they SPS manufacturing FCT Systeme GmbH Rauenstein. The purpose of the visit to SPS manufacturing company was to discuss possible improvements and modifications of the existing SPS furnace at QMUL, Mike Reece and Salvatore Grasso, April 10.

7.2 Publications

• Synthesis and spark plasma sintering of sub-micron HfB2: Effect of various carbon sources, Venugopal S, Paul A, Vaidhyanathan B, Binner JGP, Heaton A, Brown PM, J. Eur. Ceram. Soc. 34 [6] 1471–1479 (2014).

• Nuclear Applications for Ultra-High Temperature Ceramics and MAX Phases, in Ultra-High Temperature Ceramics: Materials for Extreme Environment Application, Lee WE, Harrison R, Giorgi E, Maitre A and Rapaud O, Fahrenholtz WG, Wuchina EJ, Lee WE and Zhou Y (Eds.) (Wiley 2014).


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• Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications, WG Fahrenholtz, Wuchina EJ, Lee WE and Zhou Y (Editors), (Wiley 2014).

• Qualitative analysis of hafnium diboride based ultra-high temperature ceramics under oxyacetylene torch testing at temperatures above 2100oC, Carney C, Paul A, Venugopal A, Parthasarathy T, Binner J, Katz A and Brown P, J. Eur. Ceram. Soc., 34 [5] 1045–1051 (2014).

• UHTC composites for hypersonic applications, A Paul, J Binner and B Vaidhyanathan, Chapter 7, in Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications, First Edition. Edited by William G. Fahrenholtz, Eric J. Wuchina, William E. Lee and Yanchun Zhou. The American Ceramic Society. Published by John Wiley & Sons, Inc, 144-166, (2014).

• Flash Spark Plasma Sintering (FSPS) of Pure ZrB2 Powder, Grasso S, Saunders T, Porwal H, Cedillos-Barraza O, Jayaseelan DD, Lee WE and Reece M, (accepted) J. Am. Ceram. Soc. 97 [8] 2405-2408 (2014).

• Effect of La2O3 Addition on Long-term Oxidation Kinetics of ZrB2-SiC and HfB2-SiC Ultra-high Temperature Ceramics, Zapata-Solvas E, Jayaseelan DD, Brown PM and Lee WE, J. Euro. Ceram. Soc. 34 [5] 3535-3548 (2014).

• Tough and dense boron carbide obtained by high-pressure (300 MPa) and low-temperature (1600°C) spark plasma sintering, Badica P, Grasso S, Borodianska Sky H, Xie S, Li P, Tatarko P, Reece MJ, Sakka Y and Vasylkiv O, Journal of the Ceramic Society of Japan 122 271-275 (2014).

• Sol Gel Synthesis and Formation Mechanism of Ultra High Temperature Ceramic: HfB2 - Venugopal S , Boakye EE, Paul A, Keller K, Mogilevsky P, Vaidhyanathan B, Binner JGP, Katz A and Brown PM, J. Am. Cer. Soc. 97 [1] 92–99 (2014).

• Perspectives on point defect thermodynamics, Rogal, J.Divinski, S.V., Finnis, M.W., Glensk, A., Neugebauer, J., Perepezko, J.H., Schuwalow, S., Sluiter, M.H.F., Sundman, B., Physica Status Solidi B, 251 97-129 (2014).

• An Introduction to Nuclear Waste Immobilisation, MI Ojovan and WE Lee, (2nd Edition, Elsevier 2014) pp.362.

• Thermophysical characterisation of ZrCxNy ceramics fabricated via carbothermal reduction-nitridation, R Harrison, O Ridd, DD Jayaseelan and WE Lee, J. Nuclear Mats. (2014).

• Thermal Properties of La2O3-doped ZrB2- and HfB2-based Ultra-high Temperature Ceramics, E Zapata-Solvas, DD Jayaseelan, PM Brown and WE Lee, J. Euro. Ceram. Soc 33 [15-16] 3467-3472 (2013).

• Microstructure and Rheological Properties of Titanium Carbide Coated Carbon Black Particles Synthesised from Molten Salt , J Ye, RP Thackray, S Zhang and WE Lee, J. Mater. Sci. 48 [18] 6269-75 (2013).

• UHTC–carbon fibre composites: Preparation, oxyacetylene torch testing and characterisation, A Paul, S Venugopal, JGP Binner, B Vaidhyanathan, ACJ Heaton and PM Brown, J. Euro. Ceram. Soc., 33 [2] 423-432 (2013).

• Microwave heated chemical vapour infiltration of SiC powder impregnated SiC fibre preforms, Binner JGP, Vaidhyanathan B and Jaglin D. Adv Appl Ceram. 112 [4] 235-241 (2013).

• Oxyacetylene torch testing and microstructural characterisation of tantalum carbide, A. Paul, J.G.P. Binner, A.C.J. Heaton, B. Vaidhyanathan, and P. M. Brown, Journal of Microscopy, 250 [2] 122-129 (2013).

• Thermal properties of La2O3-doped ZrB2- and HfB2-based ultra-high temperature ceramics, E Zapaa-Solvas, DD Jayaseelan, P Brown and WE Lee, J. Eur. Ceram. Soc., 33 3467-3472 (2013).

• Microstructure and High-temperature Oxidation Behaviour of Ti3AlC2/W Composites, B Cui, E Zapata-Solvas, MJ Reece, C Wang and WE Lee, J. Am. Ceram. Soc. 96 [2] 584-591 (2013).

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• Mechanical properties of ZrB2- and HfB2-based ultra-high temperature ceramics fabricated by spark plasma sintering, E Zapata-Solvas, DD Jayaseelan, P Brown and WE Lee, J. Eur. Ceram. Soc., 33, 1373-1386 (2013).

• Low-temperature spark plasma sintering of pure nano WC powder, Grasso, S, Poetschke, J, Richter, V, Maizza, G, Sakka, Y, Reece, M.J, Journal of the American Ceramic Society, 96 [6] 1702-1705 (2013).

• Highly transparent α-alumina obtained by low cost high pressure SPS (2013), Grasso, S, Yoshida, H, Porwal, H, Sakka, Y, Reece, M, Ceramics International, 39 [3], 3243-3248 (2013).

• Synthesis of High-Purity Ti3SiC2 by Microwave Sintering, Wang, Q, Hu, C, Cai, S, Sakka, Y, Grasso, S, Huang, Q, International Journal of Applied Ceramic Technology DOI: 10.1111/ijac.12065, (2013).

• The ZrC-C Eutectic Structure and Melting Behaviour: A High-temperature Radiance Spectroscopy Study, D Manara, HF Jackson, C Perinetti-Casoni, K Boboridis, MJ Welland, L Luzzi and WE Lee, J. Eur. Ceram. Soc. 33 1349-61 (2013).

• Radioactive Waste Management and Contaminated Site Clean-up: Processes, Technologies and International Experience, WE Lee, MI Ojovan and CM Jantzen (Editors), (Woodhead, 2013).

• High-temperature Oxidation Behaviour of MAX-phase Ceramics, B Cui and W E Lee, Refractories Worldforum, WINNER of 3rd place in Gustav Eirich Award 2012, 5 [1] 105-112 (2013).

• Opportunities for Advanced Ceramics and Composites in the Nuclear Sector, WE Lee, M Gilbert, S Murphy and RW Grimes, J. Am. Ceram. Soc. 96 [7] 2005-30 (2013).

• Electric field in SPS: Geometry and pulsed current effects, Grasso, S, Sakka, Y, Journal of the Ceramic Society of Japan, 1414 [121] 524-526 (2013).

• Molten Salt Synthesis and Characterization of SiC Coated Carbon Black Particles for Refractory Castables Applications, J Ye, S Zhang and WE Lee, J. Euro. Ceram. Soc. 33 [29] 2023-29 (2013).

• Effect of Oxidation on Mechanical Properties of Ultra-high Temperature Ceramics, Zapata-Solvas E, Jayaseelan DD, Brown PM and Lee WE, (accepted) J. Euro. Ceram. Soc. (2014).

• Enhanced Oxidation resistance of ZrB2/SiC Composites Through In Situ Reaction of Gadolinium Oxide in Patterned Surface Cavities, J Gonzalez-Julian, O Cedillos, S Doring, S Nolte, O Guillon and WE Lee, (submitted) J. Euro. Ceram. Soc.

• In-situ formation of oxidation resistant refractory coatings on SiC-reinforced ZrB2 ultra high temperature ceramics (UHTCs), DD Jayaseelan, E Zapata-Solvas, P Brown and WE Lee, J. Am. Ceram. Soc., 95 [4] 1247-54 (2012).

• TEM Study of the Early Stages of Ti2AlC Oxidation at 900oC, B Cui, DD Jayaseelan and WE Lee, Scripta Mat., 67 [10] 830-33 (2012).

• UHTC composites for hypersonic applications, A. Paul, D.D. Jayaseelan, S. Venugopal, E. Zapata-Solvas, J. Binner, B. Vaidhyanathan, A. Heaton, P. Brown and W.E. Lee, Bull. Am. Ceram. Soc. 91 [1] 1-8 (2012).

• Microstructure characterization of ZrB2-SiC composite fabricated by spark plasma sintering with TaSi2 additive, Hu, C., Sakka, Y., Gao, J., Tanaka, H., Grasso, S., Journal of the European Ceramic Society, 32 [7] 1441-1446 (2012).

• Use of electrophoretic impregnation and vacuum bagging to impregnate SiC powder into SiC fibre preforms, Binner JGP, Vaidhyanathan B, Jaglin D and Needham S. Int. J. Appl. Ceram. Techn. 1-11 (2013) DOI:10.1111/ijac.12143

• Perspectives on point defect thermodynamics, J Rogai, M Fiinnis, to be published in a special issue of Physica Status Solidi.

• Synthesis and Characterisation of ZrCxNy Ceramics via Carbothermic Reduction-Nitridation, R Harrison, O Ridd, DD Jayaseelan and WE Lee, (submitted) J. Nuclear Mats.


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• Screw Dislocation Assisted Spontaneous Growth of HfB2 Tubes and Rods’, S. Venugopal, A. Paul, J. Binner, B. Vaidhyanathan and P. Brown, Journal of American Ceramic Society (Accepted)

• Heat Flux Mapping of an Oxyacetylene Flame for Improved Ultra-High Temperature Testing, A. Paul, J. Binner, B. Vaidhyanathan, A. Heaton and P. Brown, (Submitted to Advances in Applied Ceramics)

• Plasma formation in electric current assisted sintering (ECAS) techniques, Theo Saunders, Salvatore Grasso, and Mike Reece, submitted to Science and Technology of Advanced Materials.

• Evaluation of the High Temperature Performance of UHTC Composites, A. Paul, J. Binner, B. Vaidhyanathan, A. Heaton and P. Brown (Waiting for Dstl approval)

7.3. Newsletters An occasional XMat Newsletter, together with the annual report, provides news and contact information for academics and industrial people work relatively close to this area of research and for dissemination at meetings and international visits. The first Newsletter was circulated in July 2013, covering the staff involved, research and equipment, visits and impacts made through this program grant. 7.4 Website The website (http://xmat.ac.uk) contains details of the staff, visitors, equipment and activities. Meetings organised through this program grant and the upcoming events are also published on the website. 7.5 Recently funded proposals associated with XMat

Jon Binner, University of Birmingham 2014 - 15 DSTL & ONRG Scaling up of transparent

nano alumina for armour protection

£67,472

Bill Lee, Imperial College London 2014-19 EPSRC, Sellafield,

NNL, NDA. DISTINCTIVE (Decommissioning, Immobilisation and Storage SoluTIons for NuClear wasTe InVEntories) consortium

£450k

2014-19, with Cambridge and The Open University

EPSRC Nuclear Energy Centre for Doctoral Training

£4M (£3M to Imperial)

2014-15 Rolls-Royce Improving Oxidation Resistance of SiC/SiC

£265k

2014-18 University of New South Wales, Australia

Synroc Durability PhD £180k

2014-18 EPSRC Nuclear Decommissioning Authority Industrial CASE

Oxidation of Uranium Carbide Nuclear Fuel

£150k

2014-17 Lloyds Register Support for Chair in Nuclear Regulation

£150k

http://xmat.ac.uk/

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7.6 Forthcoming XMat Events

Second Annual Meeting Queen Mary London 9-10 October 2014 Industry Day (TBC) February 2015 (TBC) Summer School (TBC) June 2015 (TBC) International symposium Cumberland Lodge July 2016 (TBC) Theory and modelling workshop (TBC) Late 2016 - 2017 (TBC)


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Annex-1 XMat programme milestones - First two years 1. Use of ab initio calculations to give formation energies of alternative types of lattice

defects in ZrC – C and Zr self-interstitials and interstitial clusters, Zr vacancies, antisite defects and dopant atom substitutions by end of year 1. To be achieved by end of January 2014.

2. Use of ab initio calculations to give formation energies of stacking faults and applying to

simulation of radiation damage in ZrC by end of year 2. To be achieved by end of January 2015.

3. Determination of the impact of substitution in illustrative MAX phases, e.g. of Ti by V in

Ti2AlC ceramics [(Ti,V)2AlC] on thermal properties and oxidation. Use of ab initio calculations to predict structures and elastic properties by end of year 2. To be achieved by end of January 2015

4. CALPHAD examination of binaries and hence ternary Ta-Hf-C system using existing

database by middle of year 2. To be achieved by end of July 2014. 5. Production of key compositions in Zr-Al-C and Hf-Al-C systems and measurements of

thermal and oxidation behaviour by end of year 2. To be achieved by end of January 2015.

6. Determination of the ability to control purity and stoichiometry for powders of solid

solutions in the Hf-Ta-C system, as exemplars, as a function of synthesis route and the ability to produce relatively large quantities of the powders (up to 50 g per batch) by the end of year 1. To be achieved by end of January 2014.

7. Develop carbon-carbon dies capable of achieving 100 MPa at 2000°C and silicon

carbide dies that can achieve 300 MPa at up to 1600°C before the end of year 1. This will assist us in densifying difficult compounds. To be achieved by end of December 2013.

8. Understand the influence of pulsed electrical current and mechanical loading on

densification mechanisms and rates by the end of year 1. To be achieved by end of January 2014.

9. Understand and optimise the processing conditions during reactive sintering to produce

near theoretical densification of materials with very high melting temperature (>3,000°C) in the Ta-Hf-C, Zr-Al-C and Hf-Al-C systems before the end of year 2. To be achieved by end of December 2014.

10. Developing hot forging techniques to produce high density, textured layered compounds

by the end of year 2. To be achieved by end of January 2015. 11. Development of the world’s first atmosphere controlled flash sintering furnace by the

end of year 1 and its use to make key compositions in first HfC and then binary and finally ternary systems. To be achieved by end of January 2014.

12. Progress in terms of developing a true understanding of how the presence of an

electromagnetic field can enhance the sintering of ceramic materials, initiated during year 2, completed during years 3-5.

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13. Progress in terms of producing fully dense, UHTC powder impregnated and UHTC chemically infiltrated carbon fibre reinforced composites and the first property measurements by the end of year 2. To be achieved by end of January 2015.

14. Full microstructural characterisation (including of second phases) of key base materials

e.g. ZrC, HfC by end of year 1 (14.1) and materials in the Ta-Hf-C, Zr-Al-C and Hf-Al-C systems by end of year 2 (14.2). Linking this data to the CALPHAD work will be crucial. To be achieved by end of January 2014 (milestone 14.1) and end of January 2015 (milestone 14.2).

15. Full microstructural characterisation of MAX phases such as (Ti,V)2AlC with links to

modelling and impact of V additive on ordering and, e.g., elastic and thermal properties, to be completed during years 3-5.

16. Full microstructural evolution of the oxidation mechanisms in key compositions in the

ternary systems and in those containing additives intended to improve oxidation resistance such as RE-doped ZrB2 by end of year 2. To be achieved by end of January 2015.

17. Initial laser, oxyacetylene torch and arcjet testing of compositions indicated by

modelling, processing and characterisation to be most suitable by end of year 2. 18. Initiation of global roundrobin testing exercise. To be achieved by end of January

2015. 19. Examination of oxidation mechanisms using O18 and SIMS analysis to be completed

during years 3-5. 20. Post-mortem characterisation of samples tested in previous bullet with links to FE and

microstructural modelling, to be completed during years 3-5. 21. Generation of deformation mechanism maps for ZrC, ZrB2 and HfB2 monoliths with links

between FIB microstructures, modelling and properties such as hardness, to be completed during years 3-5.

22. Linking modelling of thermal properties to empirical data at high temperatures in ZrC,

ZrB2 and HfB2 monoliths with links between FIB microstructures, to be completed during years 3-5.

Other systems will also be examined in the later years of the programme. Milestones (modelling work: after three years) • CALPHAD assessment of Ta-Hf-C and B-C-Hf-Zr systems and their associated binaries. • Theoretical investigation into relative melting points of TaC and HfC.1

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