ADVANCE MATERIAL APPLICATION

Construction application

Polymer matrix composites and especially fibre reinforced polymer (FRP) are widely utilized

inconstruction applications, including industrial and agricultural buildings.

BIOMEDICAL APPLICATION

Stainless steels for metal implants have been further developed to be Ni-free. Replacing Ni

with other alloying elements while maintaining the stability of austenitic phase,corrosion

resistance, magnetism and workability, has lead to the use of nitrogen creating FeCrN,

FeCrMoN and FeCrMnMoN systems.

Application

CFR(carbon-fiber-reinforced composites) epoxy tubing has been used to replace stainless

steel in artificial arms.

Fibrous poly(glycolic acid) (PGA) felts and poly(lactide-co-glycolide) (PLGA) fibers have

been used as surfaces and scaffolds for cartilage cell growth, where the cells produce the bulk

matrix when implanted at the site of the cartilage defect.

Alginate and Gelatin have been used to thoroughly wet Dacron fibers and seal the vascular

prosthesis, and over time they are biodegraded.( Soft-Tissue Engineering)

All-ceramic dental composites are used for stress-bearing restorations of dental crowns and

bridges.(eg. Alumina-glass composite known as In-Ceram).

For permanent implants like artificial hip joints, artificial knee joints, bone plates, screws for

fracture fixation, cardiac valve prostheses, pacemakers, and artificial hearts new alloys

include Ti-6Al-7Nb (ASTM F1295), Ti-13Nb-13Zr (ASTM F1713), and Ti-12Mo-6Zr

(ASTM F1813) are used.

Division Example of implants Type of metal

Cardiovascular Stent, Artificial valve 316L SS; CoCrMo; Ti

Ti6Al4V

Orthopaedic Bone fixation (plate, screw, pin)

Artificial joints

316L SS; Ti; Ti6Al4V

CoCrMo; Ti6Al4V; Ti6Al7Nb

Dentistry Orthodontic wire

Filling

316L SS; CoCrMo; TiNi; TiMo

AgSn(Cu) amalgam, Au

Craniofacial Plate and screw 316L SS; CoCrMo; Ti; Ti6Al4V

Otorhinology Artificial eardrum 316L SS

HIGH TEMPERATURE MATERIALS

Materials that allow operation at high temperature are essential in many industries from material

producing and processing to transportation and power generation.A metal or alloy which serves

above about 1500°C. More specifically, the materials which operate at such temperatures consist

principally of some stainless steels, superalloys, refractory metals, and certain ceramic

materials. Stainless steels, superalloys, refractory metals, and certain ceramic materials are used

at high temperature. The high temperature alloys of interest included Ni-, Fe-, Co-base

superalloys,

Cr-base alloys, and stainless steels. that offer excellent stability at temperatures exceeding 2000

°C[1] being investigated as possible thermal protection system materials, coatings for materials

subjected to high temperatures, and bulk materials for heating elements.

Advanced ceramics are distinguished by their purity and performance. They include both oxides

and non oxides and various particulate, whisker, and continuous fiber-reinforced ceramic

composites. High-purity ceramic coatings are also part of the advanced ceramics family.

Advanced ceramics encompass a set of materials that offer many of the desirable characteristics

of conventional ceramics without many of the flaws. They are best suited for high-temperature

applications in power generation, transportation, aerospace, and manufacturing where their

superior performance can justify their higher cost. For most purposes, advanced ceramic

materials can be classified as monolithics, coatings, or composites.

ceramic coatings-The objective of this concept, however, is the same as creating an entire part

from advanced ceramics: high reliability for the life of the part. Some standard ceramic coating

technologies that are used today include plasma spray, high-velocity oxy-fuel (HVOC), flame

spray ceramic coating, electron beam physical vapor deposition (EBPVD), and chemical vapor

deposition (CVD).

Refractory metal

The strength of refractory metals at high temperatures, in combination with their hardness,

makes them ideal for cutting and drilling tools.

Refractory metals are also very resistant to thermal shock, meaning that repeated heating and

cooling will not easily cause expansion, stress and cracking.

The metals all have high densities (they're heavy) as well as good electrical and heat conducting

properties.

Another important property is their resistance to creep, the tendency of metals to slowly deform

under the influence of stress.

Owing to their ability to form a protective layer, the refractory metals are also resistant to

corrosion, although they do readily oxidize at high temperatures.

Nickel based superalloy

Nickel alloys and nickel-based superalloys are known for superior resistance to both heat and

corrosion as well as low thermal expansion properties. These properties make it useful in

industries that require parts to retain stability as well as the ability to resist corrosion over a wide

range of temperatures. nickel alloys, nickel aluminum, titanium Ni3(Al,Ti) ordered intermetallic

second phase embedded in a predominantly nickel solid solution matrix such as boron, carbon

and hafnium are added to modify the grain boundaries with the intent of inhibiting grain

boundary sliding and therefore inhibiting creep which is the tendency of turbine blades (in

particular) to elongate under stress at elevated temperatures.

Aerospace and Nickel Alloy

The aerospace and aviation industries rely on nickel-based superalloys for their ability to retain

strength and resist metal fatigue in high temperatures and during drastic temperature change.

Also strong, lightweight, and aesthetic in appearance, nickel alloys are an excellent choice for

the parts and components needed for aerospace and aviation operations.

Molybdenum alloys

Molybdenum (Mo) is a refractory metallic element that readily forms hard, stable carbides and

has the sixth-highest melting point of any element. Molybdenum is most commonly used as a

high temperature, corrosion resistant metal alloy in steel, cast iron and super alloys for the

military and defense, semiconductor and specialty machine shops.

Titanium-Zirconium-Molybdenum

Niobium alloys

It can also be found in electrolytic capacitors and in the most practical superconducting alloys.

Niobium can be found in aircraft gas turbines, vacuum tubes and nuclear reactors. An alloy used

for liquid rocket thruster nozzles

Ceramic

Class of refractory ceramics that offer excellent stability at temperatures exceeding 2000 °C,

being investigated as possible thermal protection system (TPS) materials

hafnium diboride ,zirconium diboride, thorium dioxide. Alumina, Alumina-Silica and other

refractory oxide fiber materials, heating elements, plus furnace insulation.

TABLE 1 — TYPICAL MELTING POINTS OF UHTC CERAMICS

Melting point,°C (°F) Density, g/cm3

B4C 2445 (4430) 2.52

SiC 2730 (4950) 3.2

TiB2 2970 (5380) 4.52

NbB2 3050 (5520) 6.97

Zr B2 3200 (5790) 6.08

HfB2 3250 (5880) 10.5

NbC 3500 (6330) 7.6

ZrC 3530 (6390) 12.2

HfC 3890 (7030) 6.8

Material used -

metallic- Nickel-based superalloys,Copper-nickel-indium

aluminum Titanium, steel, nickel,bronze alloy disks & housings(Galling,

fretting wear resistance)

ceramic - boron nitride,hafnium carbide,

fire clay,bricks,silicate,

yttria-stabilized zirconia,

Tungsten carbide(Thermal barrier)Chrome carbide (Sliding, fretting wear

resistance) (Overheating, wear resistance)

borides, carbides, nitrides, and oxides of early transition metals

Application - 1 high velocity oxygen fuel and high energy plasma methods

2 aero-engine parts(They are specifically designed to reduce heat loss from

engine exhaust)

3 jet engines the turbine blades,exhaust pipes, headers, manifolds, turbo

housings, intakes and brackets.

4 nickel-based superalloys are the high pressure turbine blade, disc and

protect gas turbine components, increasing their efficiency and reliability

at

higher temperatures and under severe conditions.

figure1-turbine blade(nickel superalloy)

figure 2 turbine blade with coatings

Sensors and actuators

1)Piezoelectricity

Materials -Quartz ,Rochelle salt,Barium titanate, lead zirconate, and lead titanate,lead

zirconatetitanate (PZT).

Application -

Quartz crystals are used for watch crystals and for precise frequency reference

crystals for radio transmitters.

Rochelle salt produces a comparatively large voltage upon compression and was used

in early crystal microphones.

Barium titanate, lead zirconate, and lead titanate are ceramic materials which exhibit

piezoelectricity and are used in ultrasonic transducers as well as microphones. which

provide the ultrasonic sound source.

The standard piezoelectric material for medical imaging processes has been lead

zirconatetitanate (PZT).

Piezoelectric ceramic materials have found use in producing motions on the order of

nanometers in the control of scanning tunneling microscopes.

2) MEMS

MEMS (Micro-electromechanical systems) are miniature smart system constituting of a

multitude of mechanical devices that are integrated with large number of electrical elements

on a substrate of silicon.

SiC, GaAs, InP,Ge and glass are the materials used in manufacturing micro devices of

MEMS. SiO2, SiN and Polysilicon are used as structural material for biomedical and fluidic

application of MEMS.

Research is being conducted to into using ceramic materials –which are tougher,more

refractory,more inert.

Application

Accelerometer(accelerator/decelerator sensors).

Electronic display.

Data storage units.

Energy conversion devices.

Chemical detectors.

Pressure sensors(to measure blood pressure tire pressure etc.)

Mobile –silicon microphones,3D accelerator, gyroscope, micro-fuel cell.

Automobile-crash sensor, vehicle dynamic control, navigation system, antitheft

system,etc.

ACTUATORS

An actuator is a type of motor for moving or controlling a mechanism or system. It is operated

by a source of energy, typically electric current, hydraulic fluid pressure, or pneumatic pressure,

and converts that energy into motion. An actuator is the mechanism by which a control system

acts upon an environment. The control system can be simple (a fixed mechanical or electronic

system), software-based (e.g. a printer driver, robot control system), or a human or other agent.

In engineering, actuators are frequently used as mechanisms to introduce motion, or to clamp

an object so as to prevent motion. In electronic engineering, actuators are a subdivision of

transducers. They are devices which transform an input signal (mainly an electrical signal)

into motion. Electrical motors, pneumatic actuators, hydraulic pistons, relays, comb drives,

piezoelectric actuators,thermal bimorphs, digital micromirror devices and electroactive

polymers are some examples of such actuators.

fig-basic principle of an actuator

fig- control system of an actuator

fig -piezoelectric actuator

figure -carbon nanotube polymer actuator

TYPES OF ACTUATORS

● Electro-Mechanical

● Electromagnetic

● Electric motors

● DC motors

● Stepper motors

● AC induction motors

● Servomotors

● Solenoid and relays

● Piezoelectric

● Hydraulic and Pneumatics

● Valves

● Actuators – pumps, motors, and cylinders

fig- thermal actuators

fig- Underwater marine Linear Actuator

APPLICATIONS - air flow control valves in a gas turbine combustor.

clocks to compensate the error in time.

thermostat.

miniature circuit breakers to protect circuits from excess current.

patio thermometer or a meat thermometer, Electrical devices,thermocouple .

Bimetallic and Pneumatic Control pressure sensor.

Breguet's thermometer consists of a tri-metallic helix.

fluorescent lamp starters

MATERIALS USED-

bimetallic actuator

copper-steel,copper-silver,silver-nickel,nickel-copper,brass-steel

graphene and graphene oxide,stainless steel-silver ,

Aluminum / Aluminum Alloy

Copper, Brass or Bronze Alloy

Pt-TiNicu,stainless steel

flexible polymer,

piezoelectric materials such as quartz,

materials with high thermal expansion,and materials of low elastic strength.

and high sensitive to magnetic,electric,thermal feilds.

Thermostats utilize snap-acting bimetallic disc actuator. Thermostat with

bimetal coil at (2).

Shape Memory Alloy

A shape memory alloy(SMA, smart metal, memory metal, memory alloy, muscle wire, smart

alloy) is an alloy that "remembers" its original, cold‐forged shape: returning the conventional

actuators such as hydraulic, pneumatic, and motor‐based systems. Shape memory alloys have

applications in industries including medical and aerospace.

The three main types of shape memory alloys are the copper-zinc-aluminium-nickel, copper-

aluminium-nickel, and nickel-titanium (NiTi) alloys but SMA's can also be created by

alloying zinc, copper, gold, and iron.

Applications

Aircraft-Boeing, General Electric Aircraft Engines, Goodrich Corporation, NASA, and All

Nippon Airways developed the Variable Geometry Chevron using shape memory alloy that

reduces aircraft's engine noise.

Robotics-There have also been limited studies on using these materials in robotics (such as

"Roboterfrau Lara"), as they make it possible to create very light robots. Weak points of the

technology are energy inefficiency, slow response times, and large hysteresis.

Medicine-Shape memory alloys are applied in medicine, for example, as fixation devices for

osteotomies in orthopaedic surgery, in dental braces to exert constant tooth‐moving forces on

the teeth and in stent grafts where it gives the ability to adapt to the shape of certain blood

vessels when exposed to body temperature.

Composite material

1)Polymer Matrix Composite

Two types of polymers are used as matrix materials for fabrication

composites: Thermosets (epoxies, phenolics) and Thermoplastics (Low Density Polyethylene

(LDPE), High Density Polyethylene (HDPE), polypropylene, nylon, acrylics).

Application

PMCs area more mature technology than structural ceramics. With the experience gained in

military applications such as fighter aircraft androcket motor casings beginning in the 1970s,

advanced composites now have a good record of performance and reliability. They are

rapidly becoming the baseline structural material of the defense/ aerospace industry.

Boat decking - boat hulls, submersibles pressure hull, propeller shafts, masts,

bulkheads, rudders

Transport – car & rail body panels, bumper fascia, radiator grills, instrument panels,

engine components, fuel lines

Civil engineering – bridges, column wraps, cladding, repair of concrete

General engineering – pipe systems, air ductwork, power transmission drive shafts,

storage tanks, pressure vessels

Aerospace – General & military aviation fuselage, bulkhead & floor, cargo liner, wings,

landing gear, doors, rotor blades & hubs, satellite structure.

Sport – bike frames, canoes, fishing rods, archery bows, golf clubs, ski poles & skis,

surf boards, racquets

Domestic consumer – sanitary ware – baths & shower units, furnitures.

PMCs in airplanes

2)Metal Matrix Composites

The principal matrix materials for MMCs are aluminium and its alloys. To a lesser extent,

magnesium and titanium are also used, and for several specialised applications a copper, zinc

or lead matrix may be employed.

Application

Aerospace-Struts, undercarriage, guided weapons, satellites

Rail Engineering -Engine and braking components

Military-Gun barrel overwraps, missiles (aerofoils and fins, bodies and blast pipes), military

diesel component.

Electronic-Substrates and packaging, thermal management, racking, power sources and

storage

Marine-Propellers, impellers, pressurised hulls, marine diesel components

Industrial-Reciprocating and high speed machinery, precision equipment

Sport/Leisure-Rackets, cycles and frames, motor racing, golf clubs

3)Ceramic matrix composite

Carbon (C),specialsilicon carbide (SiC), alumina (Al2O3) and mullite (Al2O3–SiO2)

The important commercially available CMCs are C/C, C/SiC, SiC/SiC and Al2O3/Al2O3.

CMC names include a combination of type of fiber/type of matrix. For example, C/C stands

for carbon-fiber-reinforced carbon (carbon/carbon), or C/SiC for carbon-fiber-reinforced

silicon carbide. Sometimes the manufacturing process is included, and a C/SiC composite

manufactured with the liquid polymer infiltration (LPI) process is abbreviated as LPI-C/SiC

Application

C/SiC or SiC/SiC composites in aerojet or rocket engines

CMC braking systems (C/C for aircraft and C/C – SiC for cars)

The use of SiC/SiC composites in high temperature nuclear re (fission and fusion) for

power generation.

CMCs for Friction Applications(C / S i C Pads for Advanced Friction Systems)

Bidirectional reinforced brake disks and pads made of C/SiC (first generation

4)Natural Composite

Tree (A tree is a good example of a natural composite, consisting of cellulose (the fibrous

material) and lignin (a natural polymer) forming the woody cell walls.

Bones (In bone, the collagen acts like the resin and the mineral crystals act like the

reinforcing fibre. The mineral crystals are about 20 nanometers long (20 x 10-9 m), they are

exceptionally strong in tension, and are naturally easily bent and therefore not suitable for

structural purposes. But the combination of collagen and mineral crystals can make our bone

stronger in all dimensions)

Silky threads spun by a spider (They consist of a gel core encased by a solid structure of

aligned molecules. They can be as strong as steel)

Other Natural fibers such as sisal, hemp, flax and coconut. Flax has been used in a

flax/polypropylene under body cover for Mercedes-Benz.

Fig. showing house made up of natural composite

5) Laminates

Materials -graphite, glass, boron, and silicon carbide, and some matrix materials are

epoxies, polyimides, aluminium, titanium, and alumina.

THIN FILMS

Layer of material with one dimension much smaller than the other two is called a thin film. Here

we focus mainly on thin films attached to substrates, usually much thicker than the film.

A thin film is a layer of material ranging from fractions of a nanometer to several micrometers

in thickness. There are different kind of thin films like ceramic, metallic, organic etc. ceramic

thin films are in wide use, they have relatively high hardness and inertness of ceramic materials

make this type of thin coating of interest for protection of substrate materials against corrosion,

oxidation and wear. In particular, the use of such coatings on cutting tools can extend the life of

these items by several orders of magnitude. The other major type of optical coating is the

dielectric coating (i.e. using materials with a different refractive index to the substrate). thin

layers of materials such as magnesium fluoride, calcium fluoride, and various metal oxides,

Reflection coefficients of surfaces can be reduced to less than 0.2%,The versatility of dielectric

coatings leads to their use in many scientific optical instruments (such as lasers, optical

microscopes, refracting telescopes, and interferometers) as well as consumer devices such as

binoculars, spectacles, and photographic lenses.

Product Name: Electrolytic Manganese Dioxide(battery)

Generic Name: Manganese Dioxide

Chemical Formula / Diagram: MnO2

Applications: Dry Cells

Lithium Manganese Oxide

Product Name: Thin Film Deposition Materials

Applications: Semiconductors

Solar and photovoltaics

Flat panel displays

Magnetic recording media (rigid disks, rewritable-optical disks)

Recording heads

Thermal print heads

Thin film resistors

Material used - thorium fluoride, aluminum, titanium, zirconium, chromium and ceramic-

based

materials, silicon mono oxide(ceramic)

Titanium aluminum nitride,Titanium nitride,PdCr,

Magnesium fluoride(transparent coatings)

polyacrylic polymer,nanodiamond coatings

nano-alumina, with an average particle size of 4–6, 50–60, and ~50 nm,

(for scratch resistant coatings),inorganic nanosheets.

Application - electronic semiconductor devices,optical fibers,mirrors anti-reflective

coatings

cutting tools.Low-cost photovoltaic cell,Thin-film batteries

Insulating / conducting films; e.g. for resistors, capacitors.

Dielectric layers are sometimes applied over top of metal films, either to

provide

a protective layer (as in silicon dioxide over aluminium), or to enhance the

reflectivity of the metal film.

Application Field Examples

Optics Antireflection coating; on lenses or solar cells, ..

Reflection coatings for mirrors.

Coatings to produce decorations (color, luster, ...),

Interference filters.

CD's, DVD's and upcoming D's.

Waveguides.

Photosensitive coating of "analog" film for old camry

Chemistry Diffusion barriers.

Protection against corrosion / oxidation.

Sensors for liquid / gaseous chemicals.

Mechanics "Hard" layers (e.g. on drill bits).

Adhesion providers.

Friction reduction.

Magnetics "Hard" discs.

Video / Audio tape.

"SQUIDS"

Electricity

(without semiconductors)

Insulating / conducting films; e.g. for resistors,

capacitors.

Piezoelectric devices

fig -scratch resistant thin film coating fig-thin film coatings on ic boards

COATINGS

A coating is a covering that is applied to the surface of an object, usually referred to as the

substrate. The purpose of applying the coating may be decorative, functional, or both. The

coating itself may be an all-over coating, completely covering the substrate, or it may only cover

parts of the substrate.An example of all of these types of coating is a product label on many

drinks bottles- one side has an all-over functional coating (the adhesive) and the other side has

one or more decorative coatings.

Functional coatings may be applied to change the surface properties of the substrate, such as

adhesion, wettability, corrosion resistance, or wear resistance. In other cases, e.g. semiconductor

device fabrication (where the substrate is a wafer), the coating adds a completely new property

such as a magnetic response or electrical conductivity.Coatings may be applied as liquids, gases

or solids.

Organic Coatings

Organic coatings, applied on properly pretreated surfaces, are the most common and most

effective mode of corrosion protection for metallic objects and structures. The exterior

surfaces of corrodible metals such as iron and steel are effectively protected from their

environment by a coating system. Organic coatings have also been used for protection of

porous refractory surfaces such as cement mortar or concrete structures, which are pervious to

moisture or gases.

Organic coating provides protection either by the formation of a barrier action from the layer

or from active corrosion inhibition provides by pigments in the coating. Surface condition of

metal converted to more stable state by coating with organic compounds. These coatings delay

the generation of electromotive force, causing the corrosion of the substrate (Schweitzer, 2001).

Cathodic deposition of organic coatings has gained worldwide acceptance as a coating process

for automotive, appliance and general industrial coatings which has been adopted in

technology to provide the first prime coat to a variety of products. Among the large number of

electroconducting polymers, polypyrrole and polyaniline are the most promising conducting

polymers for corrosion protection.ex paints,lacquers ,varnishes

fig-metal coated with paints

Inorganic Coatings

Inorganic coatings can be produced by chemical action, with or without electrical assistance.

The treatments change the immediate surface layer of metal into a film of metallic oxide or

compound which has better corrosion resistance than the natural oxide film and provides an

effective base or key for supplementary protection such as paints. In some instances, these

treatments can also be a preparatory step prior to painting.

● Appearance: Products look finished, cleaner, better and longer. Color enhances metal

and promotes a solid, well-built appearance while removing the harsh metal look. Any

aluminum product can be color anodized

● Corrosion resistance: A smooth surface is retained while weathering is retarded.

Useful for food handling and marine products;

● Ease in cleaning: Any anodized product will stay cleaner longer and are easier to

clean when they do get dirty;

● Abrasion resistance: The treated metal is tough, harder than many abrasives, and is

ideal for caul plates, tooling and air cylinder applications;

● Non-galling: Screws and other moving parts will not seize, drag or jam while wear in

these areas is diminished. Gun sights, instruments and screw threads are typical

applications;

● Heat absorption: Can provide uniform or selective heat absorption properties to

aluminum for the food processing industry;

● Heat Radiation: Used as a method to finish electronic heatsinks and radiators.

Ceramic coatings

Ceramic coating is something that is used to protect parts of a vehicle or other items that are

going to get extremely hot. It is inorganic and non metallic. They are also resistant to

becoming corroded by other compounds. Something that has been coated with ceramic is

going to last longer than something that is not. In order for the ceramic to work with other

surfaces, they are usually coated. Ceramic coating can be applied by spraying or brushing on

the surface of the item needing the protection.

Ceramic coatings are typically made up of special compounds that possess stronger properties

than regular coating. Compounds in ceramic coatings include carbides, borides, nitrides, and

silicides that are hard enough to keep the material from accumulating residue and becoming

prone to breakage while in use. The sputtering process is used on the coating. This removes

certain portions of the coating material, and deposits a thin and securely bonded film onto the

surface.

Ceramic coatings protect metal parts against high temperatures, typically above 2012 degrees

Fahrenheit. When plasma-sprayed zirconia ceramic coating is used on auto parts, it works.

Advanced ceramics are distinguished by their purity and performance. They include both

oxides and non oxides and various particulate, whisker, and continuous fiber-reinforced

ceramic composites. High-purity ceramic coatings are also part of the advanced ceramics

family.Advanced ceramics encompass a set of materials that offer many of the desirable

characteristics of conventional ceramics without many of the flaws. They are best suited for

high-temperature applications in power generation, transportation, aerospace, and

manufacturing where their superior performance can justify their higher cost. For most

purposes, advanced ceramic materials can be classified as monolithics, coatings, or

composites.

ceramic coatings-The objective of this concept, however, is the same as creating an entire

part from advanced ceramics: high reliability for the life of the part. Some standard ceramic

coating technologies that are used today include plasma spray, high-velocity oxy-fuel

(HVOC), flame spray ceramic coating, electron beam physical vapor deposition (EBPVD),

and chemical vapor deposition (CVD).

Thermal barrier coatings (TBC) are highly advanced material systems usually applied to

metallic surfaces, such as gas turbine or aero-engine parts, operating at elevated temperatures,

as a form of exhaust heat management. These coatings serve to insulate components from

large and prolonged heat loads by utilizing thermally insulating materials which can sustain

an appreciable temperature difference between the load-bearing alloys and the coating

surface.[1] In doing so, these coatings can allow for higher operating temperatures while

limiting the thermal exposure of structural components, extending part life by reducing

oxidation and thermal fatigue. In conjunction with active film cooling, TBCs permit working

fluid temperatures higher than the melting point of the metal airfoil in some turbine

applications.

fig metallic coated bolts

figure -pistons coated with thermal barrier fig- ceramic coated jet blade

fig ceramic coated exhaust

Functions of coatings

1. Adhesive

2. Catalytic e.g. some self-cleaning glass

3. Light-sensitive as previously used to make photographic film

4. Protective

5. Most paints are to some extent protecting the substrate

6. Hard anti-scratch coating on plastics and other materials e.g. of titanium nitride to

reduce,scratching,

7. improve wear resistance, etc.

8. Anti-corrosion, Underbody sealant for cars ,Many plating products ,Waterproof

fabric and waterproof paper

9. Magnetic properties such as for magnetic media like cassette tapes and floppy disks

10. Electrical or electronic properties

11. Conductive coatings e.g. to manufacture some types of resistors, Insulating coatings

e.g. on magnet wires used in transformers ,Scent properties such as scratch

Coatings can be applied to metal components in order to enhance their functional properties.

Most ceramic coatings are electrically nonconductive (making them excellent insulators), have a

significantly higher level of abrasion resistance than most metals, and are capable of

maintaining their integrity under severely elevated temperatures, sometimes up to 4,500 degrees

Fahrenheit. Wear-resistant ceramics, such as titanium nitride and chromium carbide, can be

applied to work steels.Coatings are used to protect all kinds of electronic circuitry from

moisture, dust, chemicals, solvents or other types of harsh environments.

The first purpose of coatings was therefore to palliate for the poor oxidation resistance of the

base alloy (aluminide, Pt-aluminide, MCrAlY). A second type of coatings applied to high-

temperature parts are known as thermal barrier coatings (TBC). These are ceramic coatings with

very low thermal conductivity. Despite being typically 1/5 mm thin, the allow for a drop of 100-

300 oC between the gas and metal surface temperatures.

fig-coatings on tools fig steel with composite coatings

materials used - Organic coating- Paints and lacquers ,acrylic, polyurethane, epoxy,

poly-par-xylylene.

metallic coating- molybdenum, tungsten, tantalum, niobium and chromium

Sialons (based on the elements silicon, aluminium, oxygen and

nitrogen),boron carbide, copper gallium,CdTe,Cu InGa

sialon- high thermal resistance, some have extreme hardness and

others have extreme toughness.

yttria(Y2O3)-stabilised zirconia(ZrO2)

Ceramic coating- zirconia(ZrO2),3Al2O3 ∙ 2SiO2 NiCrAl/Bentonite,

applications - solar cells,furnace,internal surfaces of aircrafts and

carbon steel heat exchanger tube

The HPT blades in jet engines mainly suffer from oxidation; Pt-aluminide

coatings are preferred in these conditions and are commonly used to coat

the

main surface.

jet engine blade. Pt- Aluminised jet engine blade.