A study of the frictional, wear and contact resistance performance of tin alloy coatings

Abstract

The purpose of the present experimental study is to give an assessment of the extent to which tin alloy coatings are suitable as connector contact finishes in low power circuit applications. SnPb and SnNi alloy coatings were electrodeposited onto tin bronze and partially exposed to a thermal post-treatment. The performance of SnPb-coated contacts during mutual sliding is characterized by significant decreases in the frictional force and in its range of variation and, simultaneously, by an increase in the contact resistance by several orders of magnitude after a certain number of sliding cycles. Similar results were obtained for SnNi coatings. Investigations of the properties and structure of the coatings have clarified both the influence of heat treatment and the changes in frictional and contact resistance performance during sliding stress. For SnPb coatings a partial phase transition to metastable α-Sn due to mechanical stress was shown to occur along the wear tracks.