Element Diffusion of Al-Si Coating on Superalloy DZ4 at 1100℃

The Al-Si coating on DZ4 superalloy was prepared by slurry process.High temperature oxidation experiments of Al-Si coating on DZ4 were carried out at 1 100℃ in air and element diffusion in the oxidation was analyzed.The results indicate that Al-Si coating is composed of two layers.The outer layer is a single phase β-NiAl,while inner layer consiste of β-NiAl and carbide precipitates.The combination of inward-diffusing of Si and outward-diffusing of elements (mainly Mo and W) leds to the formation of Si-riched M6C.Si-riched M6C layer prohibited Ni/Al inter-diffusion and promoted the coating resistance to high temperature oxidation.