Research On The Microstructure And Properties Of Ni/Ti Cold Spraying Coating By Laser Remelting

This paper used the technology of mechanical alloying to preparation of the Ni/Ti alloy powder which is suitable for cold spraying. The Ni/Ti cold spraying coatings on the1lCr18Ni9Ti stainless steel substrate were obtained using different process parameters and the coating were remelted by laser treatment. SEM, EDS and XRD technologies were used to study the micro structure of the Ni/Ti coating by cold spraying and laser remelting. Cavitation erosion is one of the important performances of Ni/Ti alloy coating, It was focus on to analysis and study. The result shows that the cold spray coatings deposited with flat particles and remained layered structure of powder particles. Ni and Ti particles in the coatings by cold spraying were not oxidized and alloyed. The phase of laser remelting coating has changed. The main microstructure of coating by laser remelting is NiTi intermetallic compound which included B2and B19. The remelted coating microstructure is very dense and has obvious regional characteristic. The average micro-hardness of coating by laser remelting is827.3HV0.3which is higher than that of substrate and Ni/Ti coating by cold spraying. The remelted coating’s hardness is increased about57.6%of cold sprayed coating that is525.1HV0.3. Ni/Ti coating cavitation resistance was tested using ultrasonic vibration cavitation device and found that laser remelting coating has the smallest cavitation erosion weight lost under the same condition. The cavitation erosion stability weightlessness rate of coating by laser remelting is2.56mg/h, which were increased4times of cold sprayed coating and7times of matrix respectively. It is found that laser remelting of Ni/Ti cold spraying coating plays the role of performance optimization by comparing the study.