Influence of refractory ceramic coatings on high temperature properties of Inconel 617

TiAlN and Al2O3 thin films (2.5 - 3 μm) were deposited on the Inconel 617 by physical vapor deposition methods. The effect of coatings on the thermal stability and wear properties of the Inconel alloy after heat-treatment (annealing) in an air and a helium atmosphere at 1000 °C, 48 h has been studied. The uncoated Inconel 617, annealed in both air and helium, showed a poor wear resistance and an inferior thermal stability due to both the formation of inhomogeneous corrosion scales composed of Cr2O3 on the Inconel surface and internal oxides in sub-surface area. Although both the TiAlN and Al2O3 coatings showed an enhanced thermal corrosion resistance and an increased wear resistance for samples annealed in both air and helium, Al2O3 showed much better performance than TiAlN as a protecting layer for the Inconel 617.