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.
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
3.
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.
5.
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.
7.
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)
11.
12.
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.
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.
17.
18.
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.
20.
21.
22.
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.
24.
25.
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
28.
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.
32.
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
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.
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.