Effect of palladium plating on mechanical properties of KhN67MVTYu alloy

Effect of palladium plating in sodium melt structure and mechanical properties of KhN67MVTYu nickel alloy is investigated. Palladium plating was carried out by isothermal diffusion saturation of the samples in sodium-palladium melt at the temperature of 1000 deg C. It is shown that palladium plating in sodium melt having practically no effect on Kh67MVTYu alloy tensile properties decreases its ductulity. Decrease of the sample dutility after holding in Na-Pd melt is mainly due to the effect of formed surface layer with high content of intermetalline compounds blocking dislocation movement to the surface. Corrosion effect of transport melt and sodium manifested in nickel dissolution during palladium plating is levelled by on-coming palladium diffusion to the alloy. In this case intermetallic layer is formed on the surface and under it - solid solution on the base of palladium (70...60 mass% Pd). This results in hard braking of dissolution of alloy matrix