objects and materials used as insulators in high-voltage and high-frequency technology and made from the mineral steatite, a variety of talc. Steatite ceramics are characterized by considerable strength under static bending—up to 190 meganewtons/m2 (1,900 kilograms-force/cm2). Their permittivity varies between 5.5 and 7, and their dielectric loss (at a frequency of 1 megahertz and a temperature of 20°C), between 3 × 10–4 and 25 × 10–4.
Items made from steatite ceramics are formed by methods of ceramic technology (pressing, casting under pressure) and are fired at 1200°-1300°C. The production of steatite items, especially those having large dimensions, is made difficult by the narrow interval of temperatures at which sintering occurs (10°–40°C). One drawback of steatite ceramics is the tendency to age after long use.