Friction-wear behavior and tribochemical reactions of different ceramics in HFC-134a gas

摘要

The friction and wear properties of the ionic ceramics Al{sub}2O{sub}3 and ZrO{sub}2, and the covalent ceramics Si{sub}3N{sub}4 and SiC rubbing against an Al{sub}2O{sub}3 ball in vacuum (10{sup}(-5) Pa) and in CF{sub}3CH{sub}2F (HFC-134a) gas at 10{sup}4 Pa were investigated using a ball-on-disk type tribometer. Without exposure to air, the surface composition and chemical state of the wear tracks and debris on the disks were determined with X-ray photoelectron spectroscopy (XPS). It is found that HFC- 134a gas significantly reduces the friction and wear of all the ceramic couples, and that the ionic ceramic pairs show lower friction and wear. On the other hand, metal fluorides and/or fluorine-containing organic compounds are detected on the sliding surfaces. The differences in the friction-wear behavior of the ceramics rubbing in HFC-134a gas may be due to the products of tribochemical reactions, which are dependent on the bond type of the ceramics.