Experimental Study of Diamond-like Carbon Film on Aermet100 Steel and First-Principles Calculation of Interfacial Adhesion

Three different types of surface-modified layers of N, C, and N+C are successfully prepared on AerMet100 steel by plasma-assisted thermochemical treatment, and diamond-like carbon (DLC) films are formed on the top surfaces of the latter two. The results show that the DLC films produced by prenitriding and then carburizing (N+C) exhibit a smoother and finer morphology and higher sp³content than that without prenitriding (C). In addition, the wear resistance of the N+C specimen with a high hardness nitrided layer as the support for the outermost DLC films is superior to that of the C specimen. In view of the catalytic effect of the Fe₃C phase on the growth of DLC films, the interfacial properties of Fe₃C(001)/diamond(111) are investigated using first-principles calculations. On the basis of the most preferred Fe-terminated HCP site model, the effects of alloyed cementite (Fe₂MC) on interfacial adhesion of Fe₂MC(001)/diamond(111) are also investigated. Furthermore, the mechanisms of interfacial adhesion for two representative dopings (Zr weakened and V enhanced) are revealed in detail. These results are expected to provide a potential promising means for future experimental works on the preparation of high-performance DLC films on alloy steel surfaces by plasma carburizing.