High temperature solid particle erosion comparison of atmospheric plasma sprayed MCrAlY coatings

Abstract

Two different protective MCrAlY (NiCrAlY and NiCoCrAlY) coatings were obtained using the Atmospheric Plasma Spray (APS) method on the Inconel 718 substrate. It is aimed to inspect the rate of erosion and increase working life in last stage components of gas turbines, turbine blades and vanes. Because of the nature of exhaust, they are exposed the high temperature solid particle erosion. The High Temperature Solid Particle Erosion (HTSPE) test rig, which was specially designed and manufactured in accordance with the internationally accepted standard of ASTM G211–14, was used in the experiments. The experiments were conducted with three different air temperatures (room temperature, 300 °C and 600 °C), three different erosive particle impact angles (30°, 60° and 90°), constant particle impact velocity (∼97 m s−1) and particle size (400 μm Al2O3). SEM images, XRD analysis, EDX mapping and EDX element analysis were used to characterize the coatings. The erosion resistance results were interpreted with respect to the porosity values, hardness and surface roughness measurements of the coatings in details. As a result of the experiments, MCrAlY coatings showed ductile material behaviour compatible with erosion wear, and the cobalt element added to the coating structure contributed positively to increasing erosion resistance.