It has been previously shown that in hydrogen applications the rolling contact fatigue (RCF) life of high strength steel is directly correlated with the amount of hydrogen present in the material [1, 2]. During operation the thin oxide films that normally cover the steel are removed and fresh metal sites are generated, which act as catalysts for the decomposition of gaseous hydrogen, water or oil molecules and lead to the generation of atomic hydrogen [3]. Lubricant additives which can generate tribofilms in high pressure contacts are expected to create a barrier against the permeation of hydrogen and a number of studies have employed additives to protect the substrate and improve the life of bearing steels [4]. However, no systematic understanding exists on the importance of additive reactivity on tribofilm generation and permeation of hydrogen into the substrate. This project investigates the effect of temperature on the ability of common zinc dialkyldithiophosphate (ZDDP) antiwear additives to generate a chemical tribofilm and reduce the hydrogen content in steels.
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