Research on the Tribological Properties of Layered Kaolin Lubricant Additives

Abstract

Lubricant additives are the main means to improve the performance of lubricants. In this article, green and inexpensive layered kaolin were selected as lubricant additives, and the effects of the type of modifier, concentration, particle size of kaolin additives, and working temperatures on the tribological performance of lubricants were investigated. The results showed that the Span80 modifier can effectively improve the dispersibility and friction reduction effects of kaolin oil samples. Compared with kaolin oil samples without the modifier, the modified kaolin oil can reduce the friction coefficient by 40.9% and the wear spot diameter of the steel balls by 43.8%. The layered kaolin additive can significantly reduce the friction coefficient and wear of steel balls in lubrication, and the friction coefficient showed a trend of decreasing and then increasing with increasing kaolin additive concentration and particle size. The optimal added concentration and particle size of kaolin are 5 wt% and 2 μm, respectively, which can reduce the friction coefficient by 41.9% and 65.63% and the wear spot diameter by 12.31% and 50.72%, respectively, compared with the base oil. At five temperatures, compared with the base oil, the kaolin oil samples all showed better friction reduction and anti-wear properties. The micro and nano size of the kaolin additive, the layered structure, and the chemically reactive film generated on the surface are the main reasons for its good lubrication performance.