Publication

Abstract : Erosion studies were carried out using an air-jet erosion test rig at a velocity of 40 m s− 1 and impingement angles of 30° and 90° on uncoated Co-based Superalloy (3Fe–10Ni–20Cr–1.5Mn–0.3Si–0.08C–15W–Balance Co) as well as plasma spray NiCrAlY-, Ni–20Cr- and Ni3Al-coated superalloy specimens at room temperature. Coatings were characterised before the erosion test. The eroded surfaces have been examined by SEM/EDAX and optical Profilometer. From the EPMA analysis of the as-sprayed plasma coatings the tendency for diffusion of cobalt, tungsten and iron from the substrate into the coatings has been indicated. Ni3Al coating gave the least erosion rate at a 90° impact angle, whereas the NiCrAlY coating gave the lowest erosion rate at 30°. The Ni–20Cr coating gave the highest erosion rate with both the impact angles. The bare cobalt-based superalloy showed better erosion resistance as compared to the plasma-sprayed coatings. The overall ductile behaviour has been revealed by the scanning electron microscope for both the bare and coated alloys.