Performance and application of Ni5Al/85Ni-15C composite coating
Using Ni5Al alloy powder and 85Ni-15C alloy powder as raw materials,Ni5Al/85Ni-15C composite coatings were prepared on the surfaces of nickel based high-temperature alloy GH4169 specimens and parts using atmospheric plasma spraying technology and flame spraying technology.The microstructure,phase composition,hardness and bonding strength,microstructure,and surface state after machining of the coating were analyzed.The results showed that the lubricating phase graphite was dispersed around the nickel solid solution in the coating,and the nickel droplets covered the graphite;The bond coating has a relatively uniform structure,with few oxides,and no cracks,interface separation,delamination,or other phenomena.The Rockwell hardness of the coating surface is 66.62 HR15Y,the Huffman scratch hardness is 9.5,the microhardness of the bond coating is 175 HV0.3,and the microhardness of the top coating is 70-170 HV0.3.The bonding strength of the top coating is 11.52 MPa,and the fracture mode belongs to"mixed fracture";The bonding strength of the bond coating is 23.86 MPa,and the fracture mode belongs to"brittle fracture".After processing,the coating car is overall smooth,presenting a metallic luster and no macroscopic defects.