High-temperature oxidation characteristics of 20CrMnTi electroplated with copper

Abstract

During high-temperature forming and phase change heat treatment, the steel surface is susceptible to oxidation. This can negatively affect the surface quality of steel parts. The production of antioxidant coatings on the surface of steel parts is important for high-temperature precision forming and heat treatment. In this paper, the high-temperature oxidation tests of 20CrMnTi steel, copper, and 20CrMnTi electroplated with copper are conducted. The 20CrMnTi samples showed varying degrees of mass gain above 900 °C; the copper samples showed varying degrees of mass gain above 700 °C; and the process of mass gain for copper-plated 20CrMnTi followed the same trend as for copper during heating and holding. For heated samples of 20CrMnTi plated with copper, the copper coating was oxidized and residual copper was observed in the oxide layer. The distance between the residual copper and the surface of the sample is greater than between the residual copper and the junction of the plating layer and the substrate. Oxygen diffuses through internal defects in the material at a higher rate than copper oxidation. In this study, an oxygen diffusion model and an antioxidant protective layer model at high temperatures were suggested. The protective layer against oxidation recommended in this research is a dense coating consisting of single crystals or fine grains free of porosities and cracks.