Surface treated electrically conductive metal element and method of forming same

摘要

An electrically conductive metal element comprises an electrically conductive metal substrate having a layer of Ni-Sn alloy overlying an electrically conductive surface of the substrate and at least one layer of Ag or of Ag containing Sn overlying the Ni-Sn alloy layer. The Ni-Sn alloy(s) has a Sn-content not greater than for Ni3Sn2 for high temperature uses. In a convenient method of forming the element the Sn is applied to one or more layers of Ni in a Ag+Sn mixture and diffused into the Ni layer(s) to form the Ni-Sn alloy layer and at least one layer of Ag or of Ag containing Sn. The element may have a surface layer of SnO2 which can be formed by oxidizing residual Sn which migrates to the outer surface of the at least one layer of Ag containing Sn.