Study on Microstructure and Properties of Thermal Spray on 45 Steel

Ni-base and Fe-base powders were sprayed onto 45 steel substrate using flame spray. And the samples were remelted by heatronicheater. Then, the microstructure of coating was analyzed by OM, SEM and EDS. The resultss show that some of the porosities are detected and comprised by molten and unmelted particles. Some kind of new phase is found after the remelting process in Ni-based coatings, and EDS analysis results show that there are lots of Cr contents in the new phase which maybe generate chromic compound after remelting process and the microhardness results show that the Ni-based coating is harder than that of Fe-based coating which means the new phase is benefit to the coating.