Experimental studying tribological characteristics of lubricating oils with layered friction modifiers and their application in marine technology

Abstract

The paper presents the results of studying the lubricity of several lubricating compositions, two of which contain an antiwear additive based on a layered friction modifier - molybdenum diselenide. Oil MC-20, which does not contain functional antiwear additives, is used as a base lubricating medium and an object of comparison. Two variants for combining an antiwear additive with this oil differ in the process of initial preparation of the additive before adding it to the base lubricating oil by rotary pulsation grinding and stirring. Antiwear tests are arranged in the form of a consistent tribological rating of the given types of lubricating media at various operating time of the friction path of the test samples. The test tool is a rotary-type friction machine of an original design. There are analyzed the differences in the antiwear test methodology and the advantages of the proposed scheme over the analogous one, which is relevant for GOST R 51860-2002. Among the results of the tribological study carried out, topographic patterns of wear of test specimens, the dependence of the wear rate of tribological surfaces on contact pressures, and the dependence of the wear scar diameter on the amount of specimen wear are given. The antiwear additive has been found to contain a layered friction modifier of selenium dichalcogenide (molybdenum diselenide) type, it improves the lubricating film on friction surfaces and reduces their wear compared to the use of nonadditive oil MS-20. The wear degree of a stationary ball-shaped specimen when testing a lubricating medium with the antiwear additive is reduced by 66-85% compared to a base lubricating oil without additives. The diameter of the wear spot on a stationary specimen under these test conditions is reduced by 28-67%, which proves the effectiveness of preliminary preparation by rotary-pulsation mixing of a lubricant composition with a solid suspended base even with a relatively short preparation time.