Microstructure and adhesion characteristics of diamond-like carbon films deposited on steel substrates

Abstract

For tribological applications, the low friction coefficient and high microhardness of diamond-like carbon (DLC) films give significant advantages in cutting and forming non-ferrous materials. The inherently large residual stress of DLC films, however, prevents the depositing of thicker films. This study designed and implemented a compound interface, comprising a series of metal, metal nitride, and metal carbonitride interlayers deposited in a graded structure, between the DLC (a metal-doped a-C:H) film and M2 steel substrates. The tribological performance of the interface was evaluated using a scratch tester and ball-on-disk tribometer. Meanwhile, the failure mechanism of DLC deposited on M2 steel substrates was examined using SEM/EDS and TEM microscopy. Experimental results demonstrate an improved DLC hard coating with superior adhesion strength on the steel substrates.