Study on microstructure and erosion resistance of A12O3 reinforced Ni-base alloy coating

Al2O3 particle reinforced Ni base alloy composite coating on Q235 steel substrate was prepared by plasma spraying. The Ni-clad Al was first sprayed as the transition layer and then, ball-milling mixed G112 with different contents of Al2O3 was sprayed as the surface coatings. The structure of the coatings was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the porosity of the coatings was measured by an image analyser. Tests on erosion resistance of the coatings were carried out on a conventional erosion tester with the injection angles of 30°, 60° and 90°. The results show that the erosion resistance of the coatings increases with increasing Al2O3 content, reaches the maximum at 18wt% Al2O3 and decreases with further increase of Al2O3 content. The variation of erosion resistance of the coatings with Al2O3 content are independent of the injection angle, but are closely related to the porosity of the coatings, while the weight loss of erosion decreases with the increase of injection angle.