Tribological Behaviors of 52100 Steel in Carbon Dioxide Atmosphere

The tribological behavior of 52100 steel in a carbon dioxide (CO₂) atmosphere was investigated using a reciprocating ball-on-disk tribometer. X-ray photoelectron spectroscopy (XPS) was used to identify the adsorbed surface layers and tribochemical products. We found that CO₂can substantially reduce friction and wear of the steel. Adsorbed and reacted surface layers containing iron carbonate and/or bicarbonate play an important role in reducing friction. A disk, exposed once to CO₂atmosphere, also shows a low friction for a long time even in a vacuum environment. An optimum CO₂pressure exists for effectively reducing friction and wear. A low-pressure CO₂atmosphere is insufficient to produce iron carbonate. In contrast, high pressure engenders serious chemical wear.