Direct Observation of Thermo-Reversible Gel-Lubricants in EHL by FT-IR Micro-Spectroscopy

The tribological properties of a new unique thermo-reversible Gel-Lubricant (TR Gel-Lube) were investigated. TR Gel-Lube which includes 10-40% of amide type gel agent in base fluid, is repeatedly able to change from gel-state to liquid-state at the melting point of its gel agent. TR Gel-Lube can be used as an impregnant for porous-material due to its physical state change. TR Gel-Lube indicated lower frictional and better lubricating properties than that of conventional greases. In particular, when TR Gel-Lube was sintered in a copper-type sintered bearing, a lower friction coefficient compared with oils was observed. In this study, to clarify the mechanisms of TR Gel-Lube, the behavior of gel agent on the EHL region was investigated by ball-on-disk tribometer. It was found that gel agent played a key role in the lubricating properties. Some mechanisms such as adsorbed film formation, smooth surface formation and solid like film formation are proposed.