Polarity effect of unsymmetrical material combination on the arc erosion and contact resistance behavior

The arc duration, material transfer, contact morphology, surface composition, and contact resistance of dissimilar contact combinations of palladium to silver were experimentally examined with a breaking inductive load from 0.5 to 4.0 A for 6×10⁴ operations in air at atmosphere pressure. The test results have led to the conclusion that polarity significantly affects are erosion and electrical contact resistance behavior. By utilizing results from a previous study, it is known that cathode materials have significant influence on are erosion, i.e., through material transfer, arc duration, and erosion patterns. Contact resistance, however, is dominated by the anode material due to surface contamination, specifically anode oxidation in the late gaseous phase. Also, evidence is found in this work that material transfer between two electrodes greatly influences are erosion and contact resistance behavior