Mica is a group mineral & having Electrical & Mechanical strength, heat and moisture resistance, elastically, chemical inertness and high temperature stability. Out of several varieties of mica, the Ruby Muscovite Mica and Phlogopite Amber Mica are most useful to electrical industry.
The chemical formula of Muscovite Mica is K2O,
3Al2 O3, 6SIO2 and
that of Phlogopite Mica is K2O, 6 MgO, Al2O3, 6SiO2,
2H2 O.
The Muscovite is either colourless or some what Red or Green. Phlogopite is mostly dark in colour, golden, brown & black.
Mica is found in nature with inclusion of Quarts, Feldspar and few other Minerals. Pagmatites are the chief source of commercial muscovite mica. After mining, the raw mica is graded and cleared from large inclusion. It is then cleaved into thin sheets micsplitting. Mica is being used in various form such as : Block Mica, Mica Washer , Mica Scrap, Mica Flakes, Mica Powder, Condenser Mica, Mica Disc, Built Up Mica etc.
Mica has many uses according to its quality, for example superfine clear mica is used in condensors for Radio, Radar and Guided Missile. Fair Stained and good stained mica is used in microwave windows, Gauge Glass, Goggles and Windows Cover, Oxygen Breathing Equipment, Diaphrams etc. Stained mica is used in Baking Plates, Low Precission Condensors, Bridges and Plates, Chimney etc. Heavy stained and densely stained mica is used in house hold Heating Appliance, Commutator Rings, Electric Motors, Lamps Fuse Box, Rheostate, Induction Coils etc.
The most important use of mica is in the electrical industry because of its unique combination of properties. It has extremely high dielectric strength, low electric loss high surface and volume resistivities, excellent thermal stability, and high shear & tensile strengths. It is fire-proof, non flammable, unaffected by temperatures of 1200o F, and is resistant to the oxidizing action of electrical discharges.
Phlogopite Mica is used for the Higher Temperatures, of when A 'Softer' and more flexible Mica is needed.
