Give the properties and application of asbesto.
Asbestos: It is inorganic fibrous material. Two kinds of asbestos are available.
Chrysotile asbestos: This material is hydrated silicate of magnesium.
1. Its exact gravity varies from 2 to 2.8.
2. Asbestos is highly hygroscopic.
3. Asbestos has high dielectric losses and dielectric strength.
4. The melting temperature is 15250C.
It is found in Alaska and Africa.
1. Its fibres cannot be woven simply as the fibres are too soft or more hard and brittle.
2. Africa possesses good tensile strength.
3. Africa is highly hygroscopic.
4. Its electrical properties are poorer.
Uses: It is used in low voltage work as insulation in the form of tape, rope, board and cloth. It is impregnated along with liquid or solid resin in all such applications to enhance its mechanical and electrical properties. Asbestos used as insulator in wires and cables under high temperature conditions, like conductor insulator and layer insulator in transformer, like arcing barrier in circuit breakers and switches.