Effect of pre-transitional element X on structure and performance of TiAlXN coatings

The TiAlN-based coatings have good mechanical and anti-oxidation properties. Therefore, they have been widely used in the surface protection of typical mechanical parts, such as aero-engine compressor blades, cutting tools and precision molds. However, with the continuous improvement of the performance requirements of mechanical parts, the service conditions of the coating are becoming more and more harsh, and the reliability and service life of the protective coating are facing more severe challenges. Addition of the pre-transitional elements into TiAlN coatings is an effective method to improve their properties in various aspects for a prolonged service life. In this work, based on the ternary TiAlN coating, the effects of the addition of pre-transitional elements X (X=V, Cr, Y, Zr, Nb, Mo, Hf, Ta and W) on the structures and properties of TiAlN coatings were systematically discussed with the aid of phase diagrams. Furthermore, the composition-structure-property relationship of TiAlXN coatings was tentatively established. In view of the problems faced by adding pre-transitional elements to TiAlN coating, such as lack of phase diagram calculation assistance, failure behavior of quaternary coating in extreme environment and high cost of coating preparation equipment, the prospects of developing quaternary phase diagram of TiAlXN system combined with phase field simulation, developing TiAlN based high entropy coating and vigorously developing coating preparation technology combined with the advantages of vapor deposition technology were put forward in this paper