Discuss important properties and uses of Ceramics.
Ceramics - These are materials made by high temperature firing treatment of natural clay and specific inorganic matters. The properties of this are -
i) Ceramics are strong, dense and hard.
ii) Ceramics are not influenced by chemical action except through strong acids and alkalies.
iii) Stronger in compression than into tension.
iv) Better dielectric properties.
v) Stable at high temperatures.
Uses - The capacity to withstand high temperature, good electrical and immunity to moisture, properties make ceramics valuable for the utilization in different types of transformer bushing pins, insulators, fuse holders, sockets and plugs.
Main ceramic materials are
(a) Porcelain - This is used in low frequency applications because of high dielectric loss factor. This has low electrical resistivity.
(b) Steatite - These are low dielectric loss porcelains, utilized for variable capacitor coils, resistor shafts, bushings and switches. This is also utilized for high frequency and low voltage applications.
(c) Alumina - This has high mechanical and dielectric strength. This has high electrical resistivity and also low dielectric losses. This is chemically stable and retains its properties over a broad range of frequencies and temperature. This is used for circuit breakers, resistor cores, spark plugs, power transistors and integrated circuits.
(d) Zirconia - This has poor thermal conductivity and shock resistance. This is available with calcium or yttrium. This is used for high temperature heating components.