Influence of Trace Water and Oxygen in a Hydrogen Environment on Pure Fe Friction and Wear

Abstract

The influence of trace water and oxygen in a hydrogen environment on the sliding behavior of pure iron was studied using a newly developed pin-on-disk apparatus in a vacuum chamber equipped with an advanced gas replacement system. The hydrogen environment in the siding tests contained 0.5 to 95 ppm water and 0.07 to 2 ppm oxygen; a turbo-molecular pump was used for evacuation and a chemical filter for reducing water and oxygen in the hydrogen gas supplied to the chamber. The concentrations of water and oxygen in the hydrogen overflow from the chamber were determined using moisture and oxygen sensors, respectively. Other potential contaminant gases were analyzed using a quadrupole mass spectrometer during evacuation and were found to be insignificant. The amount of wear and the appearance of wear debris as well as the sliding surfaces were significantly different for the different concentrations of water and oxygen. The roles of these gasses are discussed.