Microstructure, mechanical and tribological properties of Ta(C, N) coatings deposited on TA15 substrates with different nitrogen partial pressure

Abstract

Purpose The purpose of this paper is to obtain the optimal N2/Ar ratio parameters for preparing Ta (C, N) coating. Three coatings with different N2/Ar ratios were prepared on the TA15 substrate, and their effects on the wear properties of the coatings were discussed. Design/methodology/approach Ta(C, N) coatings with three different N2/Ar ratios were prepared on TA15 substrates using the double cathode glow metallurgical plasma alloying technique (DGMPA) using a step-by-step diffusion method. Findings With the increase of N2/Ar flow ratio, the hardness and elastic modulus of the coating first increase and then decrease. Compared with the S1 sample (N2/Ar gas ratio 25: 75) and the S3 sample (N2/Ar gas ratio 75: 25), the S2 sample (N2/Ar gas ratio 50: 50) has better mechanical properties, with hardness increased by 48.45% and 6.8%, respectively, and elastic strain ratio increased by 22.8% and 28.5%, respectively. Moreover, the wear degree of the S2 sample is less than other samples. The wear rate of the S2 sample was 32.4% lower than the S3 sample at 300°C and 14.3% lower than the S3 sample at 500°C. Therefore, the S2 sample has the best mechanical properties and the best high temperature wear resistance. Originality/value Ta(C, N) coatings were prepared by DGMPA technology, and the wear mechanism of Ta(C, N) coatings with different N2/Ar ratios was investigated to reduce the wear rate.