Optimizing CrAlN coatings: Effects of deposition temperature on mechanical, tribological, and wettability properties

Abstract

With the aim of improving the lifespan of different steel tools by reducing their degradation, CrAlN nitride coatings were investigated. The CrAlN coatings were deposited on X38CrMoV5 steel substrates using the DC reactive magnetron sputtering process under various deposition temperatures between ambient temperature and 300 ◦C. The effects of deposition temperature were systematically explored: XRD, EDS, SEM, optical profilometer, contact angles, nanoindentation, and tribometry were carried out to establish the structural, mechanotribological, and wetting properties’ relationship. Results show that the high deposition temperature promotes the growth of (200) CrN preferentially orientation with the appearance of AlN phase. As the deposition temperature increases, the contact angle of the CrAlN surface films changes to a higher hydropholicity and the hardness of the coatings gradually increases to reach a maximum value of 28.1 GPa. The main wear mechanisms of CrAlN coating deposited at 300 ◦C against Al6061 ball are a combination of abrasive and adhesive features. This coating also has the lowest friction coefficient (0.63) and wear rate (1.72 × 10�� 3 mm3/N.m). Indeed, the preferred deposition temperature of about 300◦C could effectively adjust the microstructure and improve the mechanical and tribological properties of CrAlN coatings, thereby indicating its potential as an effective coating material for the protection of X38CrMoV5 steel in industrial fields.