Microstructural and durability evaluation of TiAlSiN coatings deposited on Ti6Al4V alloy under high-temperature conditions

Abstract

Titanium-based alloys are widely used in the defense and aerospace industries due to their high specific strength. However, their resistance to oxidation and hot corrosion under high-temperature service conditions remains limited. In this study, a TiAlSiN coating with an approximate thickness of 1.5 mu m was deposited on a Ti6Al4V alloy substrate by physical vapor deposition (PVD) to enhance its high-temperature performance. The coated specimens were subjected to isothermal oxidation tests at 900 degrees C for durations of 5, 25, and 50 h. In addition, isothermal hot corrosion tests were conducted for 1, 3, 5, and 10 h in the presence of molten salts composed of 45 wt% Na2SO4 and 55 wt% V2O5 The coating systems were comprehensively characterized before and after the oxidation and hot corrosion tests using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD) analyses. The results demonstrated that the TiAlSiN coating formed a stable and protective surface layer under high-temperature conditions, significantly improving the oxidation and hot corrosion resistance of the Ti6Al4V alloy. These findings indicate that TiAlSiN-coated Ti6Al4V alloys exhibit promising potential for high-temperature applications, particularly in the defense and aerospace sectors.