Effects of Temperature and Particle Orientation on the Electrical Conductivity of Heterogeneous Contact Materials

Abstract:
Elevated temperatures in switching devices for power engineering becomes more of a concern as the demand for size reduction continues while the rated current increases. One of the major requirements for the contact material used in maintaining a steady desired current is a good, stable electrical conductivity, which yields to a predictable behavior at elevated temperatures. In order to evaluate the influence of increasing temperature on the behavior of contact materials’ electrical conductivity, various materials (silver (Ag), silver/tungsten (Ag/W), silver/nickel (Ag/Ni), and silver/graphite (Ag/C)) were investigated including the particle orientation affects parallel and perpendicular to the contact surface. All materials were studied within temperature ranges of room temperature to 900deg C and all observations were carried out in appropriate environments where oxidation does not occur. This paper describes the measurement setup, presents and discusses results, and compares them to the literature.