Microstructural study of NiCrAlY electrodeposits

Pulse electrodeposition technique was used to co-deposit Ni with NiCrAlY powder on Ni-based high temperature alloy substrate. Pure nickel anode was immersed in a standard Watt’s bath containing fine particles of NiCrAlY powder that were entrapped during electrodeposition to form a NiCrAlY electrodeposit on cathode specimen surface. Diffusion heat treatment was conducted in argon at ≈1150°C and the samples were oxidized at 1000°C in air. Scanning and transmission electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray diffraction were used to characterize the microstructure and identify the phases. Pulse electrodeposition resulted in dense and fine-grained deposit with the formation of Al₂O₃ oxide at the coating surface after exposure to high temperature.