Analysis of surface layers and wear products by Mössbauer spectral analysis

The article presents results of Mössbauer analysis conducted in order to identify structural factors which help to increase wear resistance of steel friction pairs. Wear resistance was tested in the regime of dry friction and oxidative wear using an original tribological tester. The device measured wear in conditions of a created and regulated isothermal boundary at a precisely defined distance from contact of rubbing bodies by receiving heat generated by friction. Cleaning elements were also employed to stabilise frictional resistances. Enhanced wear resistance was observed to obtain where temperature of the friction area becomes equal to the specific temperature of a given system. Mössbauer analysis was applied to surfaces of specimens made of C45, 145Cr6 counter specimens, and wear products. Application of Mössbauer analysis helped to identify composition and structures of ferrous compounds generated by friction, including oxidative secondary structures. Factors improving wear resistance in the testing included: presence of greater quantities of FeO and Fe3O4 combined with absence of Fe2O3 in the friction area of ferrous oxides, transfer of wear particles arising from ferrite, martensite and oxides between co-acting surfaces, enrichment of the specimen surface with martensite from the hard counter specimen and martensite generated in effect of diffusion impacts.