Insulating materials of high thermal stability

The most widely used high heat-reesistance insulating binders (continuous operating temperature above 400°C) can be divided based on their chemical nature into organosilicate and metallophosphate ones. These materials can be used in a pure form, but usually they are used in combination with various excipients, inert ones or those reacting with the binder. Organosilicate materials are formed when polyorganosiloxanes or organosilicon monomers interact with inorganic minerals, such as mica, asbestos, and talc. Metal phosphates are reaction products of hydroxides or metal oxides with orthophosphoric acid. Aluminophosphates are most widely used. Aluminochromium phosphate binders have often been used in recent years. However, terms of the application of high heat-resistance binders, there are relatively few data for such materials, which is probably due to the limitations of their use for these purposes, as well as because of the difficulty of measuring the electrical properties, particularly at high temperatures. This review presents electrical characteristic of some high heat-resistance insulating materials, as well as lists of manufacturers of these materials.