Tribological Properties of Complex Calcium Sulfonate Grease with Ultrafine SiO<sub>2</sub>/MoS<sub>2</sub> Powders

For the development of complex calcium sulfonate grease containing ultrafine SiO 2 /MoS 2 powders with self-reparing performance. On the basis of the dispersion of the nanoSiO 2 particles, the effects of particle size,addition amount,load and the mass ratio of nanoSiO 2 to ultrafine MoS 2 powders on the tribological properties of commercial No.2 complex calcium sulfonate grease were systematically studied by four ball friction and wear tester. The results show that suitable particle size and addition amount of single SiO 2 and MoS 2 powders can significantly reduce the coefficient of friction (COF) and the wear scar diameter (WSD) of the grease. The composite of nanoSiO 2 and MoS 2 powder can broaden the load range of base grease and further improve the tribological properties of complex calcium sulfonate grease. When the mass ratio of nanoSiO 2 powder to MoS 2 powder is 3:7 and the total addition amount is 0.8wt%, the COF and the WSD of the grease are decreased by 53.64% and 27.08%, respectively, compared with the base grease. The two powders in the composite grease have synergy effect for improving the tribological performance and the friction stability of the grease during the process of long friction.