Dielectric measurements at elevated temperatures

It is the purpose of this paper to describe techniques that are being used to determine the dielectric constant and dissipation factor of solid insulators at temperatures up to 500°C. To establish a frame of reference, a summary of the apparatus employed over the temperature-frequency range, and of the circuits employed over the frequency range, is presented in Figure 1. Familiarity of the reader with the circuits shown is assumed, so detailed descriptions of them are not included. The following discussion will cover the construction of cells and secondary electrodes, the measuring techniques, and the rates of heating often used in determining the dielectric properties of insulators in the temperature-frequency field shown. Some problems in making measurements at temperatures above 500°C also are outlined.