Effect of Technological Parameters on Microstructure of Ni-based Alloy Coating by Laser Surface Remelting
Ni25 coating was prepared on Q235 steel substrate by thermal spraying and laser remelting process.The effects of technological parameters on microstructure were researched.Cross-section morphology of the coating was observed with optical microscope.The results show that there is an excellent metallurgical bonding between the coating and the substrate.The microstructure of the coating is mainly composed of γ-solid solution,boride,carbide + γ-solid solution eutectic,primary alloy cementite and eutectic alloy cementite.Under the conditions of other technological parameters unchanged,the microstructure of the coatings becomes smaller and more homogeneous with laser scanning speed increasing.With laser power increasing,the microstructure changes from block to small dendrite,to thick cellular crystal.