Tribo-electrification mechanism for self-mated metals in dry severe wear process: Part I. pure hard metals

The tribo-electrification and wear behavior are investigated for self-mated pure hard metal pairs of Pt, Fe, Mo, Ti and W in dry severe wear process. Results show that the tribo-electrification of pin specimen appears to have much higher possibility of positive charge with higher wear loss at pin specimen by using Pt/Pt, Fe/Fe, and Mo/Mo pairs, but it becomes to have much higher possibility of negative charge with higher wear loss at plate specimen by using Ti/Ti and W/W pairs. It is found from the SEM observations on the wear surface and wear particle that the wear for those hard metal pairs is mainly caused by the asperity removal with small wear particle. According to these results, a model for tribo-electrification mechanism is proposed. Generally, the material transfer for the self-mated hard metals mainly causes the tribo-electrification. When the material transfers from pin specimen to plate specimen, the polarity of tribo-electrification for pin specimen becomes positive, and vice versa.