The mica comes from a group of minerals made from silicated aluminum and potassium complexes, including magnesium, iron, sodium, lithium, fluorine and hydroxide. They are characterized by easy sagging, flexible and more or less elastic. The mycicles crystallize in thin overlapping sheets, sometimes large, very tiny, in the form of aggressive, more or less compact. Can be easily subdivided into thin, transparent, flexible, elastic sheets. They have good thermal and electrical insulation. They have a density between 2.8 and 3.1 and a hardness of between 2.5 and 3. They are unbreakable to acids. Mica has for many years been the best quality insulator for electric machines, being an inorganic (and therefore high temperature) high-dielectric insulator. The disadvantages of natural mica, that is, the fact that it is presented in lamella, the cost of which becomes extremely high for the larger dimensions, has been overcome with the introduction of continuous mica. This is a material obtained from mica powder, treated similarly to the cellulose paste used to make paper. The dielectric properties are high, but not the mechanical ones, so the mica paper requires a durable support. The system used today is with fiberglass support, with thermosetting impregnation (epoxy or polyester). This set represents an excellent temperature resistance insulation system, and is used for large electric machines, in particular for large synchronous generators
- Excellent Resistance to Chemical Agents
- No hygroscopicity
- Great dielectric material
- Excellent Existence to Heat Action
- Resistant to high temperatures
- Amorphous and not suitable for dimanitary applications.
- Tendentially fragile
The most important use of mica is as high-temperature electrical resistors for dynamo, transformers, electric tubes, telephones, electrodes.
See the file for technical specifications