Characteristics of Cu-W-Co and Cu-WC-Co Contact Alloys for Heavy Current Applications

In order to develop new electrical contact materials, sintered Cu-W-Co and Cu-WC-Co alloys were prepared, and their life tests were carried out using a modified ASTM type testing apparatus at AC 105 V, 50 A. The results showed that the higher cobalt content gave a smaller weight loss, a lower contact resistance and a larger welding tendency as expressed by the number of welds formed. Especially in Cu-WC-Co alloys, these characteristics were remarkable and the contact resistance maintained a very low value.Assuming that the above-stated features depended mainly on the properties of Cu-Co matrix, contact specimens of binary cast Cu-Co alloys were prepared and tested. The addition of cobalt gave an appreciable effect on the electrical contact characteristics of copper, i.e., the lowering of contact resistance and an increase of welding number were observed. These results were in good agreement with those for the sintered ternary alloys.