Green manufacturing technologies of CrTiAlN composite coatings as an alternative to chromium electroplating for piston rings

As an alternative to chromium electroplating for piston rings, one green manufacturing technology of CrTiAIN composite coatings has been introduced in this paper. In addition the mechanical and tribological properties of CrTiAIN composite coatings have been compared with chromium electroplating and CrN films. During the deposition of CrTiAIN composite coatings, the three processing steps in deposition involved were plasma ion cleaning, buffer layer deposition, and multi-component layer deposition. During the final deposition step, nitrogen concentration was controlled at 0~50 %. The metallic ratio of Cr,Ti,and Al was varied by adjusting the target currents. The nano-indenter, ehergy dispersive X-ray(EDX), scanning electron microscopy and X-ray diffraction instrument were used to investigate the mechanical property and microstructure of the coatings. The experimental results showed that the optimized quaternary Cr-Ti-AI-N coating performs better than binary CrN as well as the conventional hard chromium plating in teams of hardness and wear resistance, which was suited to use under the high temperature condition of piston rings, and they can be proposed as an alternative to hard chromium platings.