Comparative study of the structure and properties of homogeneous and gradient Ni-Cr-Al coatings

This paper compares the structure and properties of homogeneous and gradient coatings in the Ni-Cr-Al system obtained by detonation spraying. According to X-ray analysis, only the CrNi3 phase appears in the homogeneous coating, and CrNi3 , Al, and NiAl phases appear on the gradient coating. The elements distribution graphs show that a small amount of aluminum is distributed over the depth of the homogeneous coating and in the gradient coating. The distribution of aluminum in the gradient Ni-Cr-Al coating gradually increases from the depth to the surface, and a high amount of aluminum forms in the coating surface. According to EDS analysis, a small amount of aluminium is distributed on the surface of the homogeneous coating and a large amount on the gradient coating. In the gradient coating, aluminium gradually increases from the substrate surface to the coating surface. Also, the gradient coating has a higher hardness than the homogeneous coating.