Study on Friction Reduction and Wear Resistance Process and Composition of FeS Solid Lubrication Duplex Layer

Abstract

The composition of FeS solid lubrication duplex layer on 45 steel surface was studied by using SEM, EDS, AES and XPS. The results show that the sulphurized surface layer of FeS solid lubrication duplex is composed of the sulphide aggradation layer deposited on the nitrocarburized sub-surface layer and the sulphide diffusion layer formed by some S element infiltrating the nitrocarburized surface. The sulphide aggradation layer is mainly composed of FeS and FeS2, the key composition of the sulphide diffusion layer is FeS, and Fe(2/3/4)N is the key composition of the nitrocarburized sub-surface layer. The result of friction reduction and wear resistance test combined with the composition of FeS solid lubrication duplex layer explains that the friction coefficient and wear volume of the duplex layer are lower than those of the plain surface, which attribute to the relatively softer sulphurized surface layer provided self-lubricating property while the harder nitrocarburized sub-surface layer provided sufficient load bearing capacity in view of resistance to plastic deformation, so that spallation failure of the sulphurized surface layer can be effectively avoided, and they exert excellent friction reduction and wear resistance functions in different moments during rubbing process respectively.