1. CERAMICSCERAMICSBY GROUP 2BY GROUP 2

2. CERAMICSCERAMICS From Greek word From Greek word KeramosKeramos (clay) (clay) Compounds of metallic and non-metallicCompounds of metallic and non-metallicelementselements Most frequently oxides, nitrides, carbidesMost frequently oxides, nitrides, carbidesand silicatesand silicates 3. 2 Classes of Ceramics2 Classes of Ceramics TRADITIONAL CERAMICSTRADITIONAL CERAMICS Ceramic materials that are derived from common,Ceramic materials that are derived from common,naturally occurring raw materials such as claynaturally occurring raw materials such as clayminerals and quartz sand.minerals and quartz sand. A type of ceramic used in traditional applicationsA type of ceramic used in traditional applicationssuch as construction, earthenware, and glassware.such as construction, earthenware, and glassware. 4. ADVANCED CERAMICSADVANCED CERAMICS A type of ceramic exhibiting a high degree ofA type of ceramic exhibiting a high degree ofindustrial efficiency.industrial efficiency. A type of ceramic used in specialized, recentlyA type of ceramic used in specialized, recentlydeveloped applications.developed applications. Advanced ceramics are ideally suited for industrialAdvanced ceramics are ideally suited for industrialapplications that provide a physical interfaceapplications that provide a physical interfacebetween different components due to their ability tobetween different components due to their ability towithstand high temperatures, vibration andwithstand high temperatures, vibration andmechanical shock.mechanical shock. 5. 4 CLASSIFICATION OF4 CLASSIFICATION OFCERAMICSCERAMICS AMORPHOUS CERAMICSAMORPHOUS CERAMICS Lacking a definite repeating form, shape orLacking a definite repeating form, shape orstructurestructure GlassesGlasses 6. CRYSTALLINE CERAMICSCRYSTALLINE CERAMICS atoms (or ions) are arranged in a regularly repeating pattern in threeatoms (or ions) are arranged in a regularly repeating pattern in threedimensions (i.e., they have long-range orderdimensions (i.e., they have long-range order)) Crystalline ceramics are the Engineering ceramicsCrystalline ceramics are the Engineering ceramics High melting pointsHigh melting points StrongStrong HardHard BrittleBrittle Good corrosion resistanceGood corrosion resistance 7. EXAMPLE OF CRYSTALEXAMPLE OF CRYSTALSTRUCTURESTRUCTURERock salt structure(AX)(NaCl ) Spinel structure(AB2X4)(MgAl2O4) 8. BONDED CERAMICSBONDED CERAMICS Individual crystals are bonded together by a glassyIndividual crystals are bonded together by a glassymatrix, as with most clay - derived productsmatrix, as with most clay - derived products CEMENTSCEMENTS some are crystalline, while others contain bothsome are crystalline, while others contain bothcrystalline and amorphous phasescrystalline and amorphous phases 9. STRUCTURES OF CERAMICSSTRUCTURES OF CERAMICS SIMPLE CRYSTAL STRUCTURESSIMPLE CRYSTAL STRUCTURES Containing ionic or covalent bonds, or a mixture ofContaining ionic or covalent bonds, or a mixture oftwo.two. COMPLEX SILICATE STRUCTURESCOMPLEX SILICATE STRUCTURES The majority of ceramic materials, in particularThe majority of ceramic materials, in particularthose derived from clay, sand, or cement, containthose derived from clay, sand, or cement, containthe element silicon in the from of silicates.the element silicon in the from of silicates. 10. CLAYCLAYAlAl22SiSi22OO55(OH)(OH)44.. TRICALCIUM SILICATETRICALCIUM SILICATECaCa33SiOSiO55 ALUMINAALUMINAAlAl22OO33 11. TYPES OF CERAMIC PRODUCTSTYPES OF CERAMIC PRODUCTS STRUCTURALSTRUCTURAL A common traditional ceramic used in theA common traditional ceramic used in theconstruction industry. Structural ceramics includeconstruction industry. Structural ceramics includebrick, clay pipes, and concrete.brick, clay pipes, and concrete. REFRACTORIESREFRACTORIES A type of ceramic that can withstand extremelyA type of ceramic that can withstand extremelyhigh temperatures. Refractories are used inhigh temperatures. Refractories are used inindustrial furnaces.industrial furnaces. 12. WHITEWARESWHITEWARES A traditional ceramic used to make pottery andA traditional ceramic used to make pottery andporcelain. Whiteware ceramics often have a glassyporcelain. Whiteware ceramics often have a glassystructure.structure. GLASSESGLASSES A type of ceramic material characterized by itsA type of ceramic material characterized by itsnoncrystalline structure. Glasses do not solidify atnoncrystalline structure. Glasses do not solidify ata specific temperature. Instead, they graduallya specific temperature. Instead, they graduallysolidify as the temperature decreases.solidify as the temperature decreases. 13. ABRASIVESABRASIVES type of ceramic material that is very hard and weartype of ceramic material that is very hard and wearresistant. Abrasives also refer to tools used toresistant. Abrasives also refer to tools used towear away and remove material.wear away and remove material. SYNTHETICSYNTHETIC Type of ceramic material that is made fromType of ceramic material that is made fromchemicals or artificial substances rather than fromchemicals or artificial substances rather than fromnatural ones.natural ones. 14. CEMENTCEMENT Bind other materials together. Used for roads, bridges,Bind other materials together. Used for roads, bridges,buildings, dams, etc.buildings, dams, etc. ADVANCED CERAMICSADVANCED CERAMICS Advanced or Technical Ceramics are parts made from oxideAdvanced or Technical Ceramics are parts made from oxideceramics, non-oxide ceramics, or composites; each providingceramics, non-oxide ceramics, or composites; each providingunique material properties of the finished piece. The majorityunique material properties of the finished piece. The majorityof these products are manufactured with high density andof these products are manufactured with high density andlow porosity and are used in high performance applications.low porosity and are used in high performance applications. 15. APPLICATION OF ADVANCEDAPPLICATION OF ADVANCEDCERAMICSCERAMICS STRUCTURALSTRUCTURAL ELECTRICALELECTRICAL COATINGSCOATINGS CHEMICAL AND ENVIRONMENTALCHEMICAL AND ENVIRONMENTAL 16. 3 CLASSIFICATION OF3 CLASSIFICATION OFTECHNICAL CERAMICSTECHNICAL CERAMICS OXIDESOXIDES Oxidation resistantOxidation resistant chemically inertchemically inert electrically insulatingelectrically insulating generally low thermal conductivitygenerally low thermal conductivity slightly complex manufacturingslightly complex manufacturing low cost for aluminalow cost for alumina more complemore complexx manufacturingmanufacturing higher cost forhigher cost for zirconia.zirconia. 17. NON-OXIDESNON-OXIDES Low oxidation resistanceLow oxidation resistance extreme hardnessextreme hardness chemically inertchemically inert high thermal conductivithigh thermal conductivityy electrically conductingelectrically conducting difficult energy dependent manufacturing and high cost.difficult energy dependent manufacturing and high cost. 18. CERAMIC BASED COMPOSITECERAMIC BASED COMPOSITE ToughnessToughness low and high oxidation resistance (type related)low and high oxidation resistance (type related) variable thermal and electrical conductivityvariable thermal and electrical conductivity complex manufacturing processescomplex manufacturing processes high cost.high cost. 19. PROPERTIES OF CERAMICSPROPERTIES OF CERAMICS MECHANICALMECHANICAL Mechanical properties are important in structuralMechanical properties are important in structuraland building materials as well as textile fabrics.and building materials as well as textile fabrics.They include the many properties used toThey include the many properties used todescribe the strength of materials such as:describe the strength of materials such as:elasticity / plasticity, tensile strength,elasticity / plasticity, tensile strength,compressive strength, shear strength, fracturecompressive strength, shear strength, fracturetoughness & ductility (low in brittle materials),toughness & ductility (low in brittle materials),and indentation hardness.and indentation hardness. 20. ELECTRICALELECTRICAL Insulating propertiesInsulating propertiesIn contrast to Metals Ceramics have very low electricalIn contrast to Metals Ceramics have very low electricalconductivity due to Ionic-Covalent Bonding which doesconductivity due to Ionic-Covalent Bonding which doesnot form free electrons.not form free electrons. Electrical conductivityElectrical conductivityElectrical conductivity is ability of material to conductElectrical conductivity is ability of material to conductelectric current.electric current.Most of ceramic materials are dielectric (materials,Most of ceramic materials are dielectric (materials,having very low electric conductivity, but supportinghaving very low electric conductivity, but supportingelectrostatic field).electrostatic field). 21. Dielectric StrengthDielectric Strength ability of a material to prevent electronability of a material to prevent electronconductivity at high voltage. Dielectric strength isconductivity at high voltage. Dielectric strength isdetermined as value of electric field strengthdetermined as value of electric field strength(expressed in v/m) at which electron conductivity(expressed in v/m) at which electron conductivitybreakdown occurs.breakdown occurs. Dielectric ConstantDielectric Constant relative (to vacuum) ability of a material to carryrelative (to vacuum) ability of a material to carryalternating current (dielectric constant of vacuumalternating current (dielectric constant of vacuumequals to 1).equals to 1). 22. Semi-conducting propertiesSemi-conducting properties used for manufacturing varistors (resistorsused for manufacturing varistors (resistorswith non-linear current-voltagewith non-linear current-voltagecharacteristic, which are used for over-characteristic, which are used for over-voltage protection) and Positivevoltage protection) and PositiveTemperature Coefficient (PTC) Resistors.Temperature Coefficient (PTC) Resistors. Superconducting propertiesSuperconducting properties near-to-zero electric resistivitynear-to-zero electric resistivity 23. THERMALTHERMAL ThermalConductivity()ThermalConductivity()amount of heat passing in unit timeamount of heat passing in unit timethrough unit surface in a direction normalthrough unit surface in a direction normalto this surface when this transfer is drivento this surface when this transfer is drivenby unite temperature gradient underby unite temperature gradient understeady state conditions.steady state conditions. 24. ThermalExpansionThermalExpansion((CoefficientCoefficientofThermalExpansionofThermalExpansion))is relative increase in length per uniteis relative increase in length per unitetemperature risetemperature rise Heat Capacity is amount of heat required toHeat Capacity is amount of heat required toraise material temperature by one unit.raise material temperature by one unit. Specific Heat Capacity is amount of heatSpecific Heat Capacity is amount of heatrequired to raise temperature of unit mass ofrequired to raise temperature of unit mass ofmaterial by one unitmaterial by one unit 25. ThermalShockResistanceThermalShockResistanceability of material to withstand sharpability of material to withstand sharpchanges in temperature.changes in temperature. Maximum Service TemperatureMaximum Service TemperatureCeramic materials retainCeramic materials retaintheir properties at elevated temperaturestheir properties at elevated temperaturesdue to the strong ionic-covalent bonding.due to the strong ionic-covalent bonding. 26. MAGNETICMAGNETIC Isotropic ceramic magnet - equalIsotropic ceramic magnet - equalmagnetic properties in all directionsmagnetic properties in all directions Anisotropic ceramic magnetsAnisotropic ceramic magnets-magnetic properties in the direction of-magnetic properties in the direction ofpressing.pressing. 27. OPTICALOPTICAL REFRACTIONREFRACTION Light that is transmitted from one medium into another,Light that is transmitted from one medium into another,undergoes refraction.undergoes refraction. Refractive index, (n) of a material is the ratio of the speed of lightRefractive index, (n) of a material is the ratio of the speed of lightin a vacuum (c = 3 x 108 m/s) to the speed of light in thatin a vacuum (c = 3 x 108 m/s) to the speed of light in thatmaterial.material. n = c/vn = c/v 28. CHEMICALCHEMICAL Ceramics usually have a combination ofCeramics usually have a combination ofstronger bonds called ionic (occurs between astronger bonds called ionic (occurs between ametal and nonmetal and involves themetal and nonmetal and involves theattraction of opposite charges when electronsattraction of opposite charges when electronsare transferred from the metal to theare transferred from the metal to thenonmetal); and covalent (occurs between twononmetal); and covalent (occurs between twononmetals and involves sharing of atoms).nonmetals and involves sharing of atoms). 29. GENERAL COMPARISON OFGENERAL COMPARISON OFMATERIALSMATERIALSPropertyCeramicPropertyCeramicMetalPolymerMetalPolymerHardness Very High Low Very LowHardness Very High Low Very LowElastic modulus Very High High LowElastic modulus Very High High LowThermal expansion High Low Very LowThermal expansion High Low Very LowWear resistance High Low LowWear resistance High Low LowCorrosion resistance High Low LowCorrosion resistance High Low Low 30. GENERAL COMPARISON OFGENERAL COMPARISON OFMATERIALSMATERIALSPropertyCeramicPropertyCeramicMetalPolymerMetalPolymerDuctility Low High HighDuctility Low High HighDensity Low High Very LowDensity Low High Very LowElectrical conductivity Depends High LowElectrical conductivity Depends High Lowon materialon materialThermal conductivity Depends High LowThermal conductivity Depends High Lowon materialon materialMagnetic Depends High Very LowMagnetic Depends High Very Lowon materialon material 31. CERAMIC PROCESSING STEPSCERAMIC PROCESSING STEPS MILLING -MILLING - MillingMilling is the process by which materialsis the process by which materialsare reduced from a large size to a smaller size.are reduced from a large size to a smaller size.It involves the ff:It involves the ff:breaking up cemented materialbreaking up cemented materialpulverizationpulverizationattritionattritioncompressioncompressionimpactimpact 32. Crushing & Grinding (to getready ceramic powder forshaping) 33. Ball MillingBall Milling 34. BATCHING BATCHING The process of weighing oxidesThe process of weighing oxidesaccording to recipes, and preparing them for mixing andaccording to recipes, and preparing them for mixing anddrying.drying. MIXING -MIXING - occurs after batching and is performed withoccurs after batching and is performed withvarious machines, such as dry mixing ribbon mixers.various machines, such as dry mixing ribbon mixers. FORMING -FORMING - making the mixed material into shapesmaking the mixed material into shapesFORMING involves the ff:FORMING involves the ff: EXTRUSION - a process used to create objects of aEXTRUSION - a process used to create objects of afixed cross-sectional profilefixed cross-sectional profile 35. Pressing to make shaped partsPressing to make shaped parts Slip castingSlip casting DRYING is removing the water or binder fromDRYING is removing the water or binder fromthe formed materialthe formed material.. FIRINGFIRING is where the dried parts pass throughis where the dried parts pass througha controlled heating process, and the oxidesa controlled heating process, and the oxidesare chemically changed to cause sinteringare chemically changed to cause sinteringand bonding.and bonding. 36. RIBBON MIXERSRIBBON MIXERS 37. SLIP CASTINGSLIP CASTING 38. DRYING PROCESSDRYING PROCESS 39. APPLICATIONS OF CERAMICSAPPLICATIONS OF CERAMICS Aerospace: space shuttle tiles, thermalAerospace: space shuttle tiles, thermalbarriers, high temperature glassbarriers, high temperature glasswindows, fuel cellswindows, fuel cells Consumer Uses: glassware, windows,Consumer Uses: glassware, windows,pottery, Corning ware, magnets,pottery, Corning ware, magnets,dinnerware, ceramic tiles, lenses, homedinnerware, ceramic tiles, lenses, homeelectronics, microwave transducerselectronics, microwave transducers 40. Automotive: catalytic converters, ceramic filters,Automotive: catalytic converters, ceramic filters,airbag sensors, ceramic rotors, valves, sparkairbag sensors, ceramic rotors, valves, sparkplugs, pressure sensors, thermistors, vibrationplugs, pressure sensors, thermistors, vibrationsensors, oxygen sensors, safety glasssensors, oxygen sensors, safety glasswindshields, piston ringswindshields, piston rings Medical (Bioceramics): orthopedic jointMedical (Bioceramics): orthopedic jointreplacement, prosthesis, dental restoration,replacement, prosthesis, dental restoration,bone implantsbone implants Military: structural components for ground, airMilitary: structural components for ground, airand naval vehicles, missiles, sensorsand naval vehicles, missiles, sensors 41. Computers: insulators, resistors,Computers: insulators, resistors,superconductors, capacitors, ferroelectricsuperconductors, capacitors, ferroelectriccomponents, microelectronic packagingcomponents, microelectronic packaging Other Industries: bricks, cement,Other Industries: bricks, cement,membranes and filters, lab equipmentmembranes and filters, lab equipment Communications: fiber optic/laserCommunications: fiber optic/lasercommunications, TV and radiocommunications, TV and radiocomponents, microphonescomponents, microphones 42. EXAMPLES OF CERAMICSEXAMPLES OF CERAMICS Barium titanate widely used in electromechanicalBarium titanate widely used in electromechanicaltransducers, ceramic capacitors, and datatransducers, ceramic capacitors, and datastorage elements.storage elements. Bismuth strontium calcium copper oxide a high-Bismuth strontium calcium copper oxide a high-temperature superconductortemperature superconductor Boron nitride a graphite-like one used as aBoron nitride a graphite-like one used as alubricant, and a diamond-like one used as anlubricant, and a diamond-like one used as anabrasive.abrasive. Ferrite is used in the magnetic cores of electricalFerrite is used in the magnetic cores of electricaltransformers and magnetic core memory.transformers and magnetic core memory. 43. Lead zirconate titanate (PZT) PZT is used as anLead zirconate titanate (PZT) PZT is used as anultrasonic transducer, as its piezoelectric propertiesultrasonic transducer, as its piezoelectric propertiesgreatly exceed those of Rochelle salt.greatly exceed those of Rochelle salt. Magnesium diboride (MgB2) is an unconventionalMagnesium diboride (MgB2) is an unconventionalsuperconductor.superconductor. Porcelain is used for a wide range of household andPorcelain is used for a wide range of household andindustrial products.industrial products. Sialon (Silicon Aluminium Oxynitride) has high strength;Sialon (Silicon Aluminium Oxynitride) has high strength;high thermal, shock, chemical and wear resistance, andhigh thermal, shock, chemical and wear resistance, andlow density. These ceramics are used in non-ferrouslow density. These ceramics are used in non-ferrousmolten metal handling, weld pins and the chemicalmolten metal handling, weld pins and the chemicalindustry.industry. Silicon carbide (SiC) is used as a susceptor inSilicon carbide (SiC) is used as a susceptor inmicrowave furnaces, a commonly used abrasive, and asmicrowave furnaces, a commonly used abrasive, and asa refractory material.a refractory material. Silicon nitride (Si3N4) is used as an abrasive powder.Silicon nitride (Si3N4) is used as an abrasive powder. 44. Steatite (magnesium silicates) is used as an electrical insulator.Steatite (magnesium silicates) is used as an electrical insulator. Titanium carbide Used in space shuttle re-entry shields andTitanium carbide Used in space shuttle re-entry shields andscratchproof watches.scratchproof watches. Uranium oxide (UO2), used as fuel in nuclear reactors.Uranium oxide (UO2), used as fuel in nuclear reactors. Yttrium barium copper oxide (YBa2Cu3O7-x), another highYttrium barium copper oxide (YBa2Cu3O7-x), another hightemperature superconductor.temperature superconductor. Zinc oxide (ZnO), which is a semiconductor, and used in theZinc oxide (ZnO), which is a semiconductor, and used in theconstruction of varistors.construction of varistors. Zirconium dioxide (zirconia), Its high oxygen ion conductivityZirconium dioxide (zirconia), Its high oxygen ion conductivityrecommends it for use in fuel cells and automotive oxygen sensors.recommends it for use in fuel cells and automotive oxygen sensors.Most ceramic knife blades are made of this material.Most ceramic knife blades are made of this material. Partially stabilised zirconia (PSZ) is much less brittle than otherPartially stabilised zirconia (PSZ) is much less brittle than otherceramics and is used for metal forming tools, valves and liners,ceramics and is used for metal forming tools, valves and liners,abrasive slurries, kitchen knives and bearings subject to severeabrasive slurries, kitchen knives and bearings subject to severeabrasion.abrasion. 45. ENDEND