Analysis of wear behaviour of titanium carbonitride coatings

Abstract

The kinetics of chemical reactions occurring during the coating process and the wear behaviour of Ti(C,N) coatings, including variations in wear displacement with the temperature of the lower specimen, were investigated in this work. The variations in the wear displacement and the temperature of the lower specimen are regressed by an eight-order polynomial function. The lower specimens were coated by a titanium film as underlayer and three kinds of coating material including TiN, Ti(C,N) or TiC were deposited as the top layer. The Ti(C,N) coatings were prepared by varying the gas flow rates of nitrogen and acetylene to form eight kinds of specimen. The tribological behaviour demonstrated by these eight specimens is discussed. The experimental data for the atomic ratios of [C] and [N] can be well expressed using the theory of diffusion rate and the theory of reaction rate for the deposition of ceramic coatings. The variations in the wear displacement gradient with the temperature of the lower specimen can give information on the adhesive behaviour arising before and after three-body wear. The wear rates of the upper and lower specimens due to adhesive wear are dependent on the operating conditions. The specimen with a higher final wear displacement was likely to produce on the upper specimen a higher wear rate when operating at 0.705 m s −1. The thicker the adhesive layer, the lower the wear rate of the lower specimen produced. When the sliding speed was elevated to 1.41 m s −1, the specimen with a higher final wear displacement often produced a lower wear rate on the upper specimen, and also caused higher wear rates on the lower specimens.