Characteristics of the chemical reaction between pure iron implanted with molybdenum ion and S-containing lubricating oil additive

Abstract

A detailed examination of pure iron unimplanted and implanted with molybdenum ion in two doses by X-ray photoelectron spectroscopy and Auger electron spectroscopy, before and after oil-submerging and wear tests, was conducted to characterize the products between antiwear additive and surface elements of the specimen. The antiwear additive used in this study was sulfurized olefin. The results indicate that molybdenum ion implantation makes the wear resistance of pure iron lubricated with liquid paraffin increase in a large scale by means of mechanical and physical strengthening. However, the existence of Mo in the specimen presents an unfavorable effect on the wear behavior of pure iron specimen lubricated with lubricant containing sulfurized olefin. The reason is that molybdenum in the specimen reduces the amount of the adsorbed additive and reacted products (FeS, FeSO 4) which take an important role of anti-wear during wear process. From the test results, it is considered that the detrimental effect of Mo on the wear resistance of the pure iron specimen lubricated with liquid paraffin containing sulfurized olefin is related to the action of Mo and its oxide resisting diffusion of element S decomposed from additive into specimen.