A Modification of the Calculation Model for the Prediction of the Wear of Silver-Coated Electrical Contacts with Consideration of Third Bodies

Silver coatings are used in electrical contacts, in order to protect them from fretting corrosion and enhance their performance. A silver coating suffers fretting wear. Before the wear through of the silver coating, the electrical contact resistance of the contacts remains low and stable, so that the contacts can function reliably. Consequently, a precise forecast of the wear process of silver coatings is of immense interest and significance for both research and industrial applications. With regard to the forecast of the wear process of a thick silver coating, one of the main challenges is that the linear wear rate of coatings decreases disproportionally with increasing coating thickness. Moreover, many phases exist during the whole wear process and the surface conditions change accordingly. The prediction of the wear process of a thick silver coating is based on Archard's equation, but various aspects should be taken into account, in order to make a precise prediction. Firstly, the geometrical form of contacts should be considered. Then the topography which is represented by roughness and changed by deformation after the contact of the two parts should be analyzed. Thirdly, after long-term sliding, the third bodies generated in the contact interface influence the wear process greatly. This paper focuses on the third step and significantly improves the prediction precision.