Effect of Humidity on the Friction and Wear Properties of Sn

Abstract

Variation in friction and wear properties with relative humidity was obtained with an Sn pin sample on a Cu disk at a constant speed (0.4 m/s), load (6.4 N), and sliding distance (5 km), using a pin-on-disk apparatus. The influence of atmosphere on the tribological properties was investigated, including moisture ranging from 4% to 95 percent relative humidity (RH). It was found that the wear loss of the pin sample is very large at low humidity of around 5 percent RH, but it decreases and reaches saturation at about 50 percent RH. Factors characterizing the friction and wear at 50 percent RH were examined along with surface analysis of the disk. The results showed that the extensive transfer of Sn from pin to disk occurs during sliding and that the friction and wear behavior is determined by the friction and wear of an Sn sliding on Sn. An examination was carried out with an Sn pin sample on a stainless steel disk in comparison with an Sn-Cu couple. It was concluded that the friction and wear behavior is determined by the properties of the film transferred to the disk surface.