Investigation of wear mechanism by organic sulphides in vegetable oils

Tribological properties of organic sulphides in esters were examined under boundary conditions. Magnification of wear by sulphides was observed in unsaturated esters. A dumb‐bell‐shaped wear scar, composed of a ‘central area’ and a ‘border area’, was found as an intermediate of wear growth. The ‘border area’ then expanded, resulting in a large wear scar. An induction period was observed before the generation of the ‘border area’. Influences of additive concentration on the induction period were also observed. Surface analyses of worn surfaces revealed that organic oxides, sulphides (unreacted additive) and sulphoxides are present in the boundary film. Influence of auto‐oxidation of the base oil on wear mechanism was proposed. Copyright © 2007 John Wiley & Sons, Ltd.

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