Comparison Friction and Wear Properties of Overbased Calcium Sulfonate Complex Grease and Polyurea Grease
The friction and wear properties of the overbased calcium sulfonate complex grease and polyurea grease were evaluated using an Optimol SRV reciprocating friction and wear tester under the boundary lubrication conditions. The morphologies of the worn surfaces of the AISI 52100 steel discs were observed using a scanning electron microscope (SEM). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the AISI 52100 steel discs were examined by means of X-ray photoelectron spectroscopy (XPS). The results show that the overbased calcium sulfonate complex greases and polyurea grease have stable friction coefficients as low as 0.10-0.11. The calcium sulfonate complex grease has better wear resistance properties than polyurea grease, polyurea grease has better reducing friction properties than calcium sulfonate complex grease, According to the XPS analyses, it is considered that the formation of tribochemical films led to lower friction coefficient and high wear resistance.