Investigation of oxidation behaviour of AlCrN and AlTiN coatings deposited by arc enhanced HIPIMS technique

Abstract

The current study investigates the oxidation behaviour of the AlTiN and AlCrN coatings deposited using the novel arc enhanced HIPIMS technique at elevated temperature. The obtained coatings are not only a successor of the conventional coatings but can prove to be a viable option in terms of sustainable machining owing to this improved surface and sub-surface characteristics. Various techniques were utilized to provide an insight on the surface morphology, surface roughness, and variation in elemental composition with varying temperature during deposition. X-ray diffraction analysis was carried out to determine the oxides formed and change in the phases due to heating. Microscopic studies on the cross-section of the deposited samples were carried out to determine the effect of oxidation on the sub-layers. Surface morphology of the AlTiN coatings revealed the formation of flower like structures at localized sites over the film surface due to oxidation. While no such behaviour was observed in case of the AlCrN based coatings. Formation of the stable and uniform chromium oxides in comparison to sporadic aluminum-based oxides proved to be superior in terms of preventing oxidation of the coating material in the outer environment and as well as oxidation of the substrate material.