THE MECHANISM OF OXIDATIONAL WEAR

The mechanism of oxidational wear is carefully studied by microscopic analysis on the wear surfaces and by the measurement of the main facto rs occurring in the rubbing process of the pin-on-disc configuration. The results show that the occurrence of oxidational wear is governed b y the combined effects of normal load and sliding speed. When the mean temperature at the apparent contact area of the pin ranges from 140-4 00 degrees C, some kind of oxidational wear prevails. The wear rate di rectly depends upon the rate of spalling of the oxide film off the rub bed surfaces. But the spalling of the oxide film is caused by the proc ess of fatigue and, the spalled portion of the oxide is only a part of the whole thickness of the film. Therefore, the wear rate does not ha ve a linear relationship with the normal load, nor has it with the rea l contact area.