Hydrogen assisted rolling contact fatigue
In this study the decompostion of a MAC and a PFPE lubricant was investigated in a ball-on-disk sliding test under vacuum and in an RCF test on full bearings. In-situ mass spectrometry was conducted to study possible tribochemical reactions with the steel bearing surface. The degradation oft he MAC fluid was correlated with the formation of gaseous reaction products including hydrogen and various alkanes and alkenes. An oxidation reaction between the lubricant and metal oxides was identified. FEM analysis was carried out to model he contact in the ball-on-disk experiments and to extract contact surface temperature fields. Post-RCF hydrogen analysis of bearing components indicated an increased hydrogen concentration in samples lubricated with MAC fluid only. The RCF tests with PEPE did not indicate any signs of suface damage.