This document provides an overview of ceramics. It defines ceramics as compounds made from metallic and non-metallic elements, most commonly oxides, nitrides, carbides, and silicates. Ceramics are classified as either traditional or advanced, with traditional ceramics derived from natural raw materials and advanced ceramics used in specialized industrial applications. The document discusses the classification, properties, processing, and applications of various ceramic materials and products.

1. CERAMICSCERAMICS
BY 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-metallic
elementselements
 Most frequently oxides, nitrides, carbidesMost frequently oxides, nitrides, carbides
and silicatesand silicates

4. 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 clay
minerals and quartz sand.minerals and quartz sand.
 A type of ceramic used in traditional applicationsA type of ceramic used in traditional applications
such as construction, earthenware, and glassware.such as construction, earthenware, and glassware.

6.  ADVANCED CERAMICSADVANCED CERAMICS
 A type of ceramic exhibiting a high degree ofA type of ceramic exhibiting a high degree of
industrial efficiency.industrial efficiency.
 A type of ceramic used in specialized, recentlyA type of ceramic used in specialized, recently
developed applications.developed applications.
 Advanced ceramics are ideally suited for industrialAdvanced ceramics are ideally suited for industrial
applications that provide a physical interfaceapplications that provide a physical interface
between different components due to their ability tobetween different components due to their ability to
withstand high temperatures, vibration andwithstand high temperatures, vibration and
mechanical shock.mechanical shock.

8. 4 CLASSIFICATION OF4 CLASSIFICATION OF
CERAMICSCERAMICS
 AMORPHOUS CERAMICSAMORPHOUS CERAMICS
 Lacking a definite repeating form, shape orLacking a definite repeating form, shape or
structurestructure
 GlassesGlasses

9.  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 three
dimensions (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

10. EXAMPLE OF CRYSTALEXAMPLE OF CRYSTAL
STRUCTURESTRUCTURE
Rock salt structure(AX)(NaCl ) Spinel structure(AB2X4)(MgAl2O4)

13.  BONDED CERAMICSBONDED CERAMICS
 Individual crystals are bonded together by a glassyIndividual crystals are bonded together by a glassy
matrix, 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 both
crystalline and amorphous phasescrystalline and amorphous phases

14. 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 of
two.two.
 COMPLEX SILICATE STRUCTURESCOMPLEX SILICATE STRUCTURES
 The majority of ceramic materials, in particularThe majority of ceramic materials, in particular
those derived from clay, sand, or cement, containthose derived from clay, sand, or cement, contain
the element silicon in the from of silicates.the element silicon in the from of silicates.

15.  CLAYCLAY
AlAl22SiSi22OO55(OH)(OH)44..
 TRICALCIUM SILICATETRICALCIUM SILICATE
CaCa33SiOSiO55
 ALUMINAALUMINA
AlAl22OO33

16. TYPES OF CERAMIC PRODUCTSTYPES OF CERAMIC PRODUCTS
 STRUCTURALSTRUCTURAL
 A common traditional ceramic used in theA common traditional ceramic used in the
construction industry. Structural ceramics includeconstruction industry. Structural ceramics include
brick, clay pipes, and concrete.brick, clay pipes, and concrete.
 REFRACTORIESREFRACTORIES
 A type of ceramic that can withstand extremelyA type of ceramic that can withstand extremely
high temperatures. Refractories are used inhigh temperatures. Refractories are used in
industrial furnaces.industrial furnaces.

19.  WHITEWARESWHITEWARES
 A traditional ceramic used to make pottery andA traditional ceramic used to make pottery and
porcelain. Whiteware ceramics often have a glassyporcelain. Whiteware ceramics often have a glassy
structure.structure.
 GLASSESGLASSES
 A type of ceramic material characterized by itsA type of ceramic material characterized by its
noncrystalline structure. Glasses do not solidify atnoncrystalline structure. Glasses do not solidify at
a specific temperature. Instead, they graduallya specific temperature. Instead, they gradually
solidify as the temperature decreases.solidify as the temperature decreases.

23.  ABRASIVESABRASIVES
 type of ceramic material that is very hard and weartype of ceramic material that is very hard and wear
resistant. Abrasives also refer to tools used toresistant. Abrasives also refer to tools used to
wear away and remove material.wear away and remove material.
 SYNTHETICSYNTHETIC
 Type of ceramic material that is made fromType of ceramic material that is made from
chemicals or artificial substances rather than fromchemicals or artificial substances rather than from
natural ones.natural ones.

26.  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 oxide
ceramics, non-oxide ceramics, or composites; each providingceramics, non-oxide ceramics, or composites; each providing
unique material properties of the finished piece. The majorityunique material properties of the finished piece. The majority
of these products are manufactured with high density andof these products are manufactured with high density and
low porosity and are used in high performance applications.low porosity and are used in high performance applications.

27. APPLICATION OF ADVANCEDAPPLICATION OF ADVANCED
CERAMICSCERAMICS
 STRUCTURALSTRUCTURAL
 ELECTRICALELECTRICAL
 COATINGSCOATINGS
 CHEMICAL AND ENVIRONMENTALCHEMICAL AND ENVIRONMENTAL

29. 3 CLASSIFICATION OF3 CLASSIFICATION OF
TECHNICAL 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.

30.  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.

31.  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.

33. PROPERTIES OF CERAMICSPROPERTIES OF CERAMICS
 MECHANICALMECHANICAL
 Mechanical properties are important in structuralMechanical properties are important in structural
and 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 to
describe 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, fracture
toughness & ductility (low in brittle materials),toughness & ductility (low in brittle materials),
and indentation hardness.and indentation hardness.

34.  ELECTRICALELECTRICAL
 Insulating propertiesInsulating properties
In contrast to Metals Ceramics have very low electricalIn contrast to Metals Ceramics have very low electrical
conductivity due to Ionic-Covalent Bonding which doesconductivity due to Ionic-Covalent Bonding which does
not form free electrons.not form free electrons.
 Electrical conductivityElectrical conductivity
Electrical conductivity is ability of material to conductElectrical conductivity is ability of material to conduct
electric 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 supporting
electrostatic field).electrostatic field).

35.  Dielectric StrengthDielectric Strength
 ability of a material to prevent electronability of a material to prevent electron
conductivity at high voltage. Dielectric strength isconductivity at high voltage. Dielectric strength is
determined 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 conductivity
breakdown occurs.breakdown occurs.
 Dielectric ConstantDielectric Constant
 relative (to vacuum) ability of a material to carryrelative (to vacuum) ability of a material to carry
alternating current (dielectric constant of vacuumalternating current (dielectric constant of vacuum
equals to 1).equals to 1).

36.  Semi-conducting propertiesSemi-conducting properties
 used for manufacturing varistors (resistorsused for manufacturing varistors (resistors
with non-linear current-voltagewith non-linear current-voltage
characteristic, which are used for over-characteristic, which are used for over-
voltage protection) and Positivevoltage protection) and Positive
Temperature Coefficient (PTC) Resistors.Temperature Coefficient (PTC) Resistors.
 Superconducting propertiesSuperconducting properties
 near-to-zero electric resistivitynear-to-zero electric resistivity

37.  THERMALTHERMAL
 Thermal Conductivity (λ)Thermal Conductivity (λ)
amount of heat passing in unit timeamount of heat passing in unit time
through unit surface in a direction normalthrough unit surface in a direction normal
to this surface when this transfer is drivento this surface when this transfer is driven
by unite temperature gradient underby unite temperature gradient under
steady state conditions.steady state conditions.

38.  Thermal Expansion Thermal Expansion ((Coefficient Coefficient
of Thermal Expansionof Thermal Expansion))
is relative increase in length per uniteis relative increase in length per unite
temperature risetemperature rise
 Heat Capacity is amount of heat required toHeat Capacity is amount of heat required to
raise material temperature by one unit.raise material temperature by one unit.
 Specific Heat Capacity is amount of heatSpecific Heat Capacity is amount of heat
required to raise temperature of unit mass ofrequired to raise temperature of unit mass of
material by one unitmaterial by one unit

39.  Thermal Shock ResistanceThermal Shock Resistance
ability of material to withstand sharpability of material to withstand sharp
changes in temperature.changes in temperature.
 Maximum Service TemperatureMaximum Service Temperature
Ceramic materials retainCeramic materials retain
their properties at elevated temperaturestheir properties at elevated temperatures
due to the strong ionic-covalent bonding.due to the strong ionic-covalent bonding.

40.  MAGNETICMAGNETIC
 Isotropic ceramic magnet - equalIsotropic ceramic magnet - equal
magnetic properties in all directionsmagnetic properties in all directions
 Anisotropic ceramic magnetsAnisotropic ceramic magnets
-magnetic properties in the direction of-magnetic properties in the direction of
pressing.pressing.

41.  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 light
in 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 that
material.material.
 n = c/vn = c/v

42.  CHEMICALCHEMICAL
 Ceramics usually have a combination ofCeramics usually have a combination of
stronger bonds called ionic (occurs between astronger bonds called ionic (occurs between a
metal and nonmetal and involves themetal and nonmetal and involves the
attraction of opposite charges when electronsattraction of opposite charges when electrons
are transferred from the metal to theare transferred from the metal to the
nonmetal); and covalent (occurs between twononmetal); and covalent (occurs between two
nonmetals and involves sharing of atoms).nonmetals and involves sharing of atoms).

43. GENERAL COMPARISON OFGENERAL COMPARISON OF
MATERIALSMATERIALS
Property Ceramic Property Ceramic Metal PolymerMetal Polymer
Hardness Very High Low Very LowHardness Very High Low Very Low
Elastic modulus Very High High LowElastic modulus Very High High Low
Thermal expansion High Low Very LowThermal expansion High Low Very Low
Wear resistance High Low LowWear resistance High Low Low
Corrosion resistance High Low LowCorrosion resistance High Low Low

44. GENERAL COMPARISON OFGENERAL COMPARISON OF
MATERIALSMATERIALS
Property Ceramic Property Ceramic Metal PolymerMetal Polymer
Ductility Low High HighDuctility Low High High
Density Low High Very LowDensity Low High Very Low
Electrical conductivity Depends High LowElectrical conductivity Depends High Low
on materialon material
Thermal conductivity Depends High LowThermal conductivity Depends High Low
on materialon material
Magnetic Depends High Very LowMagnetic Depends High Very Low
on materialon material

45. CERAMIC PROCESSING STEPSCERAMIC PROCESSING STEPS
 MILLING -MILLING - MillingMilling is the process by which materialsis the process by which materials
are 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 material
pulverizationpulverization
attritionattrition
compressioncompression
impactimpact

46. Crushing & Grinding (to get
ready ceramic powder for
shaping)

47. Ball MillingBall Milling

48.  BATCHING –BATCHING – The process of weighing oxidesThe process of weighing oxides
according to recipes, and preparing them for mixing andaccording to recipes, and preparing them for mixing and
drying.drying.
 MIXING -MIXING - occurs after batching and is performed withoccurs after batching and is performed with
various 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 shapes
FORMING involves the ff:FORMING involves the ff:
 EXTRUSION - a process used to create objects of aEXTRUSION - a process used to create objects of a
fixed cross-sectional profilefixed cross-sectional profile

49.  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 from
the formed materialthe formed material..
 FIRINGFIRING is where the dried parts pass throughis where the dried parts pass through
a controlled heating process, and the oxidesa controlled heating process, and the oxides
are chemically changed to cause sinteringare chemically changed to cause sintering
and bonding.and bonding.

50. RIBBON MIXERSRIBBON MIXERS

51. SLIP CASTINGSLIP CASTING

53. DRYING PROCESSDRYING PROCESS

54. APPLICATIONS OF CERAMICSAPPLICATIONS OF CERAMICS
 Aerospace: space shuttle tiles, thermalAerospace: space shuttle tiles, thermal
barriers, high temperature glassbarriers, high temperature glass
windows, 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, home
electronics, microwave transducerselectronics, microwave transducers

55.  Automotive: catalytic converters, ceramic filters,Automotive: catalytic converters, ceramic filters,
airbag sensors, ceramic rotors, valves, sparkairbag sensors, ceramic rotors, valves, spark
plugs, pressure sensors, thermistors, vibrationplugs, pressure sensors, thermistors, vibration
sensors, oxygen sensors, safety glasssensors, oxygen sensors, safety glass
windshields, piston ringswindshields, piston rings
 Medical (Bioceramics): orthopedic jointMedical (Bioceramics): orthopedic joint
replacement, prosthesis, dental restoration,replacement, prosthesis, dental restoration,
bone implantsbone implants
 Military: structural components for ground, airMilitary: structural components for ground, air
and naval vehicles, missiles, sensorsand naval vehicles, missiles, sensors

56.  Computers: insulators, resistors,Computers: insulators, resistors,
superconductors, capacitors, ferroelectricsuperconductors, capacitors, ferroelectric
components, 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/laser
communications, TV and radiocommunications, TV and radio
components, microphonescomponents, microphones

57. EXAMPLES OF CERAMICSEXAMPLES OF CERAMICS
 Barium titanate widely used in electromechanicalBarium titanate widely used in electromechanical
transducers, ceramic capacitors, and datatransducers, ceramic capacitors, and data
storage 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 a
lubricant, and a diamond-like one used as anlubricant, and a diamond-like one used as an
abrasive.abrasive.
 Ferrite is used in the magnetic cores of electricalFerrite is used in the magnetic cores of electrical
transformers and magnetic core memory.transformers and magnetic core memory.

58.  Lead zirconate titanate (PZT) PZT is used as anLead zirconate titanate (PZT) PZT is used as an
ultrasonic transducer, as its piezoelectric propertiesultrasonic transducer, as its piezoelectric properties
greatly exceed those of Rochelle salt.greatly exceed those of Rochelle salt.
 Magnesium diboride (MgB2) is an unconventionalMagnesium diboride (MgB2) is an unconventional
superconductor.superconductor.
 Porcelain is used for a wide range of household andPorcelain is used for a wide range of household and
industrial 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, and
low density. These ceramics are used in non-ferrouslow density. These ceramics are used in non-ferrous
molten metal handling, weld pins and the chemicalmolten metal handling, weld pins and the chemical
industry.industry.
 Silicon carbide (SiC) is used as a susceptor inSilicon carbide (SiC) is used as a susceptor in
microwave furnaces, a commonly used abrasive, and asmicrowave furnaces, a commonly used abrasive, and as
a refractory material.a refractory material.
 Silicon nitride (Si3N4) is used as an abrasive powder.Silicon nitride (Si3N4) is used as an abrasive powder.

59.  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 and
scratchproof 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 high
temperature superconductor.temperature superconductor.
 Zinc oxide (ZnO), which is a semiconductor, and used in theZinc oxide (ZnO), which is a semiconductor, and used in the
construction of varistors.construction of varistors.
 Zirconium dioxide (zirconia), Its high oxygen ion conductivityZirconium dioxide (zirconia), Its high oxygen ion conductivity
recommends 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 other
ceramics 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 severe
abrasion.abrasion.

62. ENDEND