The tribological properties of low temperature ion sulfidized coating of steels

In this paper, an ion sulfidizing process has been introduced. An FeS coating, a solid lubricant, was produced on the surface of metal parts by glow discharge. This technology has such advantages as simple process, low cost, thick sulfide coating, little heat deformation and excellent tribological properties. The coatings on 45- and 18Cr2Ni4WA were scale-like distributed and had a loose structure according to analysis with SEM and XRD. The phase of the sulfide layer was mainly FeS, and with increased temperature, some Fe1−XS was produced. The pair of 18Cr2Ni4WA–Cu was tribologically tested on a MM-200 tester. The result showed that the friction coefficients of the treated specimen pairs were remarkably lower than those of untreated ones, and with the increase of normal loads, the coefficient decreased. 45-steel was also tested. The contact fatigue resistance of sulfidized parts was approximately one order higher than that of unsulfidized ones.