Activated Sintering of Tungsten-Copper Contact Materials

Abstract

Nickel or cobalt additions were made to W–Cu compacts to determine whether the substitution of Co for Ni would improve their sintering characteristics and their properties as contact materials. For alloys with small proportions of Cu, Co was more effective in promoting sintering than Ni, whereas in those alloys with a high Cu content neither addition affected the sintering process. Despite their different sintering characteristics, no significant differences were detected in the contact angles of the liquid phases in W–Cu, W–Cu–Co or W–Cu–Ni alloys. The improved sintering of low-Cu alloys containing Co appears to be related to the formation of W₆Co₇ intermetallic compound on the surface of the W particles.