Tribological Behaviors of 440C Bearing Steel in a Carbon Dioxide Atmosphere

摘要

The effect of carbon dioxide (CO{sub}2) on tribological behaviors of 440C bearing steel has been investigated using a reciprocating ball-on-disk tribometer. The original and the worn surfaces of disk specimens have been analyzed by X-ray photoelectron spectroscopy to identify tribochemical products. Results show that CO{sub}2 gas is able to lubricate the steel. The formed iron carbonate layer on the surface plays an important role in reducing friction. CO{sub}2 is very effective in reducing friction and wear under relatively low pressure, and chemical wear of the surface layers was accelerated under high CO{sub}2 pressure, resulting in high friction and severe adhesive wear. By adding a small amount of water vapor in high pressure to the CO{sub}2 atmosphere, the adhesive wear can be effectively repressed, and this addition does not affect low-friction behavior.