Preparation of Ni₃Al(Cr)Coating by High Energy Micro-arc Alloying and Its High Temperature Oxidation Resistance

Ni3Al(Cr)coating was prepared on the surface of the K3 alloy by high energy micro-arc alloying process.The preparation process was optimized.The oxidation behavior of the coating at 1 000 ℃ was analyzed.The results show that the microcrystalline coating could be obtained on the K3 alloy by high energy micro-arc alloying process.The coating obtained by using as-cast Ni3Al(Cr)intermetallic compound as electrode material could get a metallurgy bonding with the matrix bonded.The coating could form a continuous protective Al/Cr-rich oxide film in a shorter time because of the grain refinement,while the cast electrode and K3 alloy could not form continuous and compact oxide film.The coating had better oxidation resistance than the as-cast Ni3Al(Cr)and K3 alloy,while the formed amount of NiO and spinel decreased.