Tribophysical and tribochemical effects of a thermoplastic polyimide

The sliding friction and wear characteristics of a thermoplastic polyimide (PI) were investigated under different PV conditions using a pin-on-disc we ar tester. The tribological characteristics of the PI were divided into thr ee wear regions on the basis of the wear degree (slight wear, medium wear a nd severe wear). The friction coefficient of the PI in slight wear was stab le. In the medium wear and severe regions, the friction coefficients of the Pl varied over a wide range, and was unstable. The reason for the variatio ns of friction and wear in the different wear regions was attributed to the rising of PI surface temperature, which led to the variations of the physi cal state of PI friction surface layer. XPS analysis indicated that carbona tion occurred on the friction surface during sliding. It was proved that th e reaction product may reduce the friction coefficient. (C) 2000 Kluwer Aca demic Publishers.