Ceramics are materials made by higher temperature firing treatment of natural clay and certain inorganic matters. Structurally ceramics are crystal bonded together. Other materials used with clay in different type of ceramics are Alumina, Quartz, talc, magnetite, Feldspar etc. A few of the known ceramics are composed as following:
Insulator Porcelain: Clay, Quartz, Barium, Feldspar;
High Frequency Porcelain: Clay Quartz Barium Carbonates;
Steatite: Clay, Tale, magnetite.
A simple manufacturing process for ceramics involves mixing finely ground clay and metal oxide with water just sufficient to make a paste which is shaped according to requirements. This mould is finally dried and fried at a temperature ranging between 1200 degree C and 1700 degree C.
Main features of ceramics:
(1) Ceramics are hard, strong and dense;
(2) Not affected by chemical action expect by strong acids and alkalise;
(3) Stability at high temperature likely to occur in electrical engineering applications;
(4) Excellent dielectric properties;
(5) Weak in impact strength. They cannot be used as self supporting thin films like paper, cotton etc.