2023 Volume 62 Issue 1 Pages 227-231
The numbers of connector pins for automotive applications have been increasing rapidly. Therefore, it is increasingly important to reduce the insertion force for workability. In this study, we investigated the effect of cold atmospheric pressure plasma treatment on the suppression of adhesion between electroplated materials, and the main cause of increase in the friction coefficient.
The plasma treatments with various gas species were performed on three types of plating：hard Ag, hard Ag–C composite, and Sn. The friction coefficients of the hard Ag and the hard Ag–C composite decreased by the treatments, especially using oxygen–containing gas species. The contact resistance increased after the treatment. The increment of the resistance was smaller at higher contact loads. Oxygen was detected on the surface of the hard Ag and the hard Ag–C composite after the treatment, suggesting that the surface oxidation of Ag is the main reason in the reduction of the friction coefficient and the increase in resistance. The thicknesses of the silver oxide layer were measured to be single nanometers and presumed to be thin enough to be broken on the contact force of the connector, having little adverse effect on the contact reliability. The plasma treatment is highly productive and suitable for continuous processing on automotive connectors that require low insertion force and contact reliability.
