The effect of Ti and Si on the mechanical and electrochemical behaviors of the AlCrN coating deposited by CAPVD on 304SS

Abstract This study aimed to investigate the effect of adding titanium (Ti) and silicon (Si) elements on the mechanical and electrochemical properties of the AlCrN‐based coating. For this purpose, a cathodic arc physical vapor deposition machine was used. Scanning electron microscopy, X‐ray diffraction, and nanoindentation tests were utilized for morphological, microstructural, and mechanical characterization of the coatings. The hardness value and plastic deformation index of CrAlN‐based coating increase with the presence of Si element. The mechanical properties improvement is attributed to the reduction of crystallite size as well as to the tendency of the coating structure to become amorphous. The specimens were subjected to 3.5 wt% NaCl solution to electrochemical impedance corrosion and potentiodynamic polarization tests. The results showed that by increasing the coatings’ titanium content, the coatings’ corrosion resistance improved. Moreover, by adding 3% and 5% of Si elements to the coatings’ composition, the corrosion resistance of the AlCrTiSiN coatings was enhanced by 35% and 78%, respectively. Improving the corrosion resistance of the AlCrN‐based coatings by adding the Si element is attributed to the change in the microstructure and reduction in the porosity of the coatings.