Impact of aluminum content upon the microstructure of Ni-Cr-Al gradient coatings

Abstract

Studied the aluminium concentration in the composite powder NiCr-Al influences the structure of NiCr-Al gradient coatings. Gradient coatings based on NiCr-Al were obtained by detonation spraying, with a phased reduction in the barrel filling volume with acetylene-oxygen gas mixture from 50% to 25%. The coatings' microstructure was analyzed across different aluminum concentrations: 15%, 20%, and 30%. By adjusting the aluminum concentration in the powder mix, we achieved coatings with a gradient formation. The findings indicated that the phase composition of the gradient coating is significantly influenced by the Al mass percentage. The findings suggest a powder composition of 80%NiCr and 20%Al to produce NiCr-Al coatings with a good gradient structure.