Derating of Electrical Contacts with Varying Surface Roughness

This study aimed to evaluate the impact of contact surface roughness on the performance characteristics of M12-type electrical contacts, with particular emphasis on current and thermal derating parameters. Three samples were prepared, all made from the same conductive material CuZn42, in accordance with identical geometric and technological specifications, differing in the surface roughness value: Rz = 2 μm, representing high surface finish quality, and Rz = 10 μm, representing lower quality. The results showed that the surface roughness of the contact significantly affects the thermal and electrical properties of the tested contacts. Surfaces with lower roughness (Rz = 2 μm) exhibited better electrical conductivity, lower contact resistance, and slower temperature rise as the current load increased. In contrast, contacts with higher roughness (Rz = 10 μm) showed a faster temperature rise and a reduction in the maximum allowable current at higher ambient temperatures. These results could be useful in the design of systems requiring reliability, particularly in high-power devices.