Effect of peening as pretreatment for DLC coatings on magnesium alloy

DLC coating can contribute to the excellent mechanical and tribological properties of materials. In most cases, a metallic film (e.g., Cr or Si) is used as an interlayer between DLC film and steel substrate to improve the adhesion of the coating. In this work, the adhesion of DLC film on magnesium alloy by substituting the interlayer formation with a pretreatment by peening was examined. The magnesium alloy specimens were preliminarily peened using two kinds of media (SiC and graphite) and then treated by the RF capacitively coupled plasma CVD method. A mixture of 50% methane (CH4) and 50% hydrogen (H2) was used as the processing gas. The peening as pretreatment with the SiC medium made it possible to deposit DLC films on the magnesium alloy without an interlayer.