Influences of LaF₃ on microstructure and performance of laser cladding layer in-situ fabricated

In-situ Ni-based TiC composite coatings with LaF₃ were made by laser cladding,and the microstructure,composition profiles,microhardness,wear and corrosion properties of the coatings were analyzed by using electron probe micro-analyzer(EPMA),transmission electron microscope(TEM),scanning electron microscope(SEM),microhardness instrument,M-2000 Friction and Wear Tester,and M398 Electrochemical corrosion systems.The results show that after adding moderate rare earth LaF₃,the microstructure presents more homogeneous,the fineness of grain becomes finer,TiC distributes better and heterogeneous phase decreases.When the content of LaF₃ is 1%,the highest microhardness is got;when it is 2%,the optimal wear and corrosion resistance properties are obtained;but when adding excessive rare earth LaF₃,both the microstructure and properties will get worse.