1. Synthesis,Properties and Uses.
CERAMICS

2. WHAT ARE CERAMICS??
 Ceramics are inorganic materials with many
different properties generally known for their
strength and heat resistance.
 They may be amorphous, partly crystalline or fully
crystalline.
 They are either formed from a molten mass that
solidifies on cooling, formed and matured by the
action of heat, or chemically synthesized at low
temperatures using, for
example, hydrothermal or sol-gel synthesis.

4. BASIC MANUFACTURE PROCESS
MILLING →
BATCHING→MIXING→FORMING →
DRYING → FIRING → ASSEMBLY
1.Milling
 Ceramic materials are reduced by size
for efficient processing.
2.Batching
 It is the process of weighing the oxides
according to their requirement and
preparing them for mixing and drying.

5. 3.Mixing
 All materials are churned together and wetted most
of the times to enable appropriate shaping
4. Forming
 It Is making the mixed material into shapes.
5.Drying
 It is removing the water or the binding component
from the formed material.
6.Firing
 It means giving the final form to the product.

6. BASIC CLASSIFICATION OF
CERAMICS:

7. ALUMINA
 Alumina or aluminium oxide( Al2O3 )is one of the most widely
used oxide ceramic.
 It naturally occurs in its crystalline form -Corundum.
How it is produced?
1. First Bauxite is purified by the Bayer process:
 AlO(OH) + H2O + NaOH → NaAl(OH)4Al(OH)3 + NaOH →
NaAl(OH)4
 Except for SiO2, the other components of bauxite do not
dissolve in base. Upon filtering the basic mixture, Fe2O3 is
removed. When the Bayer liquor is cooled,
Al(OH)3 precipitates, leaving the silicates in solution.
 NaAl(OH)4 → NaOH + Al(OH)3The solid Al(OH)3 Gibbsite is
then calcined (heated strongly) to give aluminium oxide
 2 Al(OH)3 → Al2O3 + 3 H2O.

8. PROPERTIES AND USES OF
ALUMINA
PROPERTIES:
 Electrical insulator
 Aluminium oxide is insoluble in water
USES
 It is a major component, of the cue tip "chalk" used
in billiards. Also it is used in some CD polishing and
scratch-repair kits
 Used in ballistic armoured vests and can repel large-
calibre rifle fire.
 Alumina can form glass if it is alloyed with calcium
oxides, but its difficult to produce bulk quantities due to
unavailability.

9. SILICON CARBIDE
 It is also known as carborundum.

10. PRODUCTION
1.α-SiC:
The primary reaction is:
SiO2(Sand) + 3C SiC +2CO
{
SiO2 +C SiO (g)+CO (g)
SiO (g)+2C SiC+CO (g)
} At 2000-3000 degree Celsius
2.β-SiC:
SiCl4 + CH4 SiC+4HCl
At 1000-1500 degree Celsius

11. SILICON: PROPERTIES AND USES
PROPERTY USE
 Durability and low cost of the
material
 High sublimation temperature
of SiC
 High thermal conductivity, and
high maximum current density
 High voltage-dependent
resistance
 Grinding, honing, water-jet cutting
Bearings and furnace parts.
 Semiconductor material in
electronics.
 Lightning arresters

12. OTHER APPLICATIONS
OF SIC
 Grains of silicon carbide are sintered to form ceramics which
are used in car brakes , ceramic plates and protective vests.
 Silicon-infiltrated carbon-carbon composite is used for high
performance "ceramic" brake discs, as it is able to withstand
extreme temperatures.

13. ZIRCONIA(ZIRCONIUM DIOXIDE)
 Zirconia is nothing but Zirconium
dioxide (ZrO2).
 It is produced by calcinating zirconium
compounds, exploiting its high thermal
stability.
PROPERTIES:
 Monoclinic crystal structure at room
temperature
 Thermal Insulator and very hard.

14. APPLICATIONS OF ZIRCONIA
CUBIC ZIRCONIA (CZ) IS THE CUBIC CRYSTALLINE
FORM OF ZIRCONIUM DIOXIDE (ZrO2).
 It is a excellent replacement for diamonds as it is
almost similar to it.
 Used as an oxygen sensor in exhaust systems

16. FIBRE REINFORCED CERAMICS
 Consists of Ceramic fibers embedded in a
ceramic matrix, thus forming a ceramic fiber
reinforced ceramic (CFRC) material.
PROCEDURE FOR FORMATION:
1. Lay-up and fixation of the fibers, shaped as
the desired component
2. Infiltration of the matrix material
3. Final machining

17. IMPORTANT CERAMIC
APPLICATIONS
 Silicon nitride parts are used in ceramic ball bearings.
Their higher hardness means that they are much less
susceptible to wear.
 Boron carbide and silicon carbide are used in fixed
amounts to manufacture cockpit of planes.
 Artificial bone and teeth.
 High-temperature reusable surface insulation (HRSI)
in Space shuttles
 Most widely used in Pottery
 Ceramic coatings are applied to engines

18. AN INTERESTING FACT
 In 1980s, Toyota researched production of an adiabatic ceramic
engine which can run at a temperature of over 3300 °C.
 Ceramic engines do not require a cooling system and hence allow a
major weight reduction and therefore greater fuel efficiency. Fuel
efficiency of the engine is also higher at high temperature.
 In a metallic engine, much of the energy released from the fuel must
be dissipated as waste heat in order to prevent a meltdown of the
metallic parts.
 Despite all of these desirable conventional properties, such engines
are not in production because the manufacturing of ceramic parts in
the requisite precision and durability is difficult. Imperfection in the
ceramic leads to cracks, which can lead to potentially dangerous
equipment failure.

19. ADIABATIC ENGINE

20. THANK YOU FOR
YOUR KIND
ATTENTION