Effect of the Composition of the Lubricating Medium on the Structure of Surface Layers Formed by the Friction of a Servovite Film

Abstract

The tribological characteristics of a brass–steel friction pair in aqueous solutions of saturated carboxylic acids are studied. With an increase in the length of the carbon radical in the acid molecule used as the organic component of the lubricant composition upon the friction of brass on steel, the coefficient of friction decreases and wear reduces. A servovite film is found to form on tribocoupled surfaces during frictional interaction. In the series of monobasic carboxylic acids R–COOH (R = C_nH_2n + 1, n = 0–5) used as a lubricating medium, from formic acid to caproic acid, the roughness of the film surface decreases and its continuity increases. The servovite film is formed by copper nanoclusters of predominantly ellipsoidal shape up to 40 nm in height, tightly packed and directed along the slip of the counterbody.