Synthesis and characterizations of modified Y2O3 nanoparticles aluminide coating on nickel alloy IN625

In this study, the effect of doping Y2O3 Nano particles on aluminide coating on the nickel base alloy substrate (IN625alloy) by pack cementation process with single step. The pack powder consists of Al-Y2O3−NH4Cl (as activator) -Al2O3 (filler material). The Y2O3 doped-aluminide coating specimens were characterized by many tests and inspections, microstructure test, thickness measurement, microhardness test and X-ray diffraction analysis. As temperature above 900°C layer became unstable. When the temperature arises to 1100°C, aluminide coating became stable and suitable thickness. After coating layers were synthesized, the nickel diffusion was outward from substrate and the aluminum diffusion was inward from mixture to substrate by parabolic law. It was observed that the coating is composed of top layer, transition layer and interdiffusion layer. The highest value of hardness was (986HV) at doped 2%Y2O3 on aluminide coating in comparison to alloy substrate (266 HV). The coating thickness decreases with increasing the Nano Y2O3 content in aluminide coating.