Tribological properties of polyamide (PA6) in self-mated contacts and against steel as a stationary and moving body

Abstract

The time for which each contacting body is exposed to a tribological contact affects its interface temperature, third-body and tribofilm formation, and, as a result, the overall tribological behaviour, which may be particularly relevant with very dissimilar material pairs. This work focuses on the tribological properties of unreinforced polyamide (PA6) in self-mated contacts or against steel (SS) as a stationary (SS/PA6) or a moving contact (PA6/SS) body under dry-sliding conditions. Moreover, the effects of the contact pressure and the sliding velocity were investigated for these contacts. In addition, the contact conditions were carefully controlled with measurements of the specimen's surface temperature using an infrared camera. The results show that the tribological behaviour indeed depends significantly on the contact configuration. The tribological properties of the stationary steel pin sliding against a rotating polymer disc (SS/PA6), as well as of a self-mated PA6/PA6 contact, depended substantially on the contact conditions used. In contrast, the contact configuration of a stationary PA6 pin sliding against a rotating steel disc (PA6/SS) showed only a negligible effect on changes in the sliding speed and the load. Moreover, this was clearly the best-performing contact in the study and the beneficial effect is explained by the ability of a rotating disc to remove the heat from the contact zone and, consequently, to lower the temperatures generated in the tribological contact.