Catalytic growth of diamond-like carbon on Fe₃C-containing carburized layer through a single-step plasma-assisted carburizing process

This article reports a study on catalytic growth of diamond-like carbon (DLC) on the Fe₃C-containing carburized surface layer of M50NiL steel through a single-step plasma-assisted carburizing process. The catalytic effect of Fe₃C on DLC growth was investigated by means of X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical and tribological tests demonstrate that the DLC growth endows the treated specimens with higher hardness, lower coefficient of friction and increased wear resistance than traditional carburization layer. First-principles calculations were conducted to verify the experimental observations and elucidate the mechanism for the catalytic growth of DLC on Fe₃C surface. This study demonstrates that DLC can simultaneously form during carburization of steel under suitable processing conditions, resulting in a combination of DLC and carburized layers through a single-step process with help of the catalytic effect of Fe₃C. This finding shows a promising approach to maximize the benefits of carburization treatment, and provides new clues for facilitating DLC production and improving traditional surface treatments for steels.