Effects of elevated temperature on tribological behavior of polyimide and polyimide/mesoporous silica nanocomposite in dry sliding against GCr15 steel

Friction and wear behavior of a thermoplastic polyimide (PI) and its mesoporous silica (MPS) reinforced nanocomposite was investigated at temperatures up to 300 °C in dry sliding against GCr15 steel. Experimental results showed that elevated temperature produced significant promoting effect on the tribological properties of pure PI. Specific wear rate of the PI at temperatures up to 300 °C was reduced by more than one order of magnitude, while the coefficient of friction (COF) was also significantly decreased. This dramatic improvement of the tribological properties was attributed to the improved quality and ease formation of transfer film at elevated temperatures. For the PI/MPS nanocomposite at elevated temperatures, moderate improvement of the tribological properties was manifested at applied load lower than 10 N, while friction and wear was slightly deteriorated at higher applied load. Wear mechanism was elaborately investigated from points of view of wear topography, transfer film and wear debris evolution as functions of elevated temperature and applied load.