On the Difference in the Action of Anti-Wear Additives in Hydrocarbon Oils and Vegetable Triglycerides

This paper examines the difference between the effects of anti-wear additives on vegetable and hydrocarbon-based oils. Knowledge of the specific influence of additives on the anti-wear properties of vegetable oils is necessary to increase the efficiency of the development of biodegradable lubricating oils. In addition, this is interesting from the point of view of clarifying the mechanism of action of AW/EP additives. The effect of non-toxic additives—adipic acid monoester and hexadecanol—on hydrocarbon hydrocracking oil and vegetable oil was compared. The comparison was carried out in rolling contact with sliding, sensitive to the separating ability of the oil. It was found that in hydrocarbon oil, the additive affects the parameters of the hydrodynamic friction regime. When adding an additive to vegetable oil, the hydrodynamic parameters do not change. The additive acts in the same way in both oils during mixed and transient modes. The obtained results are compared to available data, and an explanation of the difference is proposed based on the AW/EP mechanism of action. It is concluded that there is little chance of enhancing vegetable oil properties for hydrodynamic bearings. Search criteria for additives that effectively influence the antifriction and anti-wear properties of vegetable oils in mixed and boundary friction modes are proposed.