Study of Effect of Metal Oleates on Mixed and Boundary Lubrication

The article presents the results of a study of metal oleates for friction with mixed and boundary lubrication. The objects of study are copper (II), zinc (II), and tin (II) oleates. The boundary friction coefficient in a "steel - steel" friction pair was measured at an II5018 testing machine according to the "roller-block" scheme at different temperatures. The friction coefficient for mixed lubrication was measured in a plain bearing during the transition between hydrodynamic and boundary lubrication. Hersey-Stribeck curves were constructed for the journal bearing. The investigated additives have the most significant effect on the friction coefficient when introduced into the oil without other additives and less significant effect when introduced into the engine oil. The investigated metal oleates affect the conditions for the transition between hydrodynamic and boundary lubrication in a journal bearing. The results show that copper oleate reduces the contact friction coefficient by 7-15 % when added to engine oil. Zinc oleate has a similar effect and reduces the friction coefficient by 5.5-8.5 %. Tin oleate reduces the friction coefficient by 23.5-31 %.