Critical temperatures of contact materials

The influence of cathode temperatures on the dielectric strength of contact materials is investigated in the temperature region between 300 and 1600 K. Experimental results show that contact materials investigated in this paper have certain critical temperatures. Below the critical temperatures, the dielectric strengths of the materials are equal to or greater than those at room temperature; but above the critical temperatures, the dielectric strengths decrease rapidly. The critical temperatures for CuSe and CuCr are about 1200 and 1300 K, respectively. The critical temperature for Cu is also 1200 K. The influence of temperature on dielectric strength is discussed