Abstract:

Using metallocene poly alpha-olefins (mPAO) and poly α-olefin (PAO40) as base oils, and complex lithium soap as thickener, a kind of lithium complex greases were prepared. The high-speed reciprocating friction and wear testing machine was used to investigate the effect of molybdenum disulfide, molybdenum dithiocarbamates, zinc silicate additives and their mixtures on the friction and wear properties of complex lithium grease on steel - steel friction pair. Scanning electron microscopy (SEM) and energy spectrum analysis (EDS) were employed to analyze the worn surfaces. The tribological properties of the composites are significantly improved with addition of 5% molybdenum dithiocarbamate, 2% molybdenum disulfide or 4% zinc silicate in the lithium grease. The lithium grease using mPAO as base oil has better tribological properties compared to poly α-olefin as base oil.

Key words: metallocene poly alpha-olefins, additive, lithium grease, steel-steel friction pair, friction and wear performance