A comparative study of the lubricating properties of various types of base oils containing hydrogen emulsions

The aim of this study is to evaluate the lubricating performance of various base oils in a hydrogen-enriched environment. Experiments were conducted wherein base oils were emulsified with meticulously calibrated hydrogen concentrations, followed by a series of friction and wear measurements. Elemental analysis was performed on the worn surfaces, providing further insight into the wear mechanism. The findings of this study highlight the pronounced effect of hydrogen on the lubrication of pure water emulsions of Class IV 4 base oils, with the Class V 5-1 base oils showing optimal lubricating performance in hydrogen-enriched conditions. SEM images at high magnification scanning revealed the presence of a protective friction film on the surfaces of the wear scars in each sample. X-ray photoelectron spectroscopy (XPS) identified traces of metal sulfide within the friction film, which may play a role in reducing friction. The formation of this friction film is likely a contributing factor to the enhanced lubricating performance of the base oil. These findings contribute a substantial foundation for the development of standards for evaluating the performance of hydrogen internal combustion engine oils.