The Electrical Performance of Ceramic Dielectrics at Elevated Temperatures

Some recent developments have emphasized the need for information concerning the temperature at which dielectrics can be operated without electrical breakdown. This paper deals primarily with porcelain, but some data are included on the performance of steatite. glass, and zircon compositions. Data are presented on the variation in resistivity of the materials with varying temperature and also with varying voltage gradient. From the temperature-resistivity curves a method is developed for approximating the combination of temperature and voltage gradient which will result in electrical failure. Supporting data in the form of breakdown tests, made at various temperatures, are included. These tests include practical insulator forms as well as prepared test specimens.