In situ laser deposition of NiTi intermetallics for corrosion improvement of Ti-6Al-4V alloy

NiTi intermetallic coatings were fabricated on the surface of Ti-6Al-4V alloy by melting Ni and Ti powders using laser metal deposition (LMD) process. The effects of NiTi reinforcement content on the microstructure, hardness and corrosion properties of the coatings were examined. The results show that the deposited coatings are characterized by NiTi, NiTi2 and NiTi3 intermetallic phases. An appreciable increase in corrosion resistance is obtained for all the coatings, and Ti55Ni45 coating shows the highest corrosion resistance; while coatings Ti50Ni50 and Ti45Ni55 follow in that succession. The reinforcement materials are proven to be corrosion resistant in the tested environment, and the effect of Ti is more dominant.