Microstructure and electrochemical characterization of laser melt-deposited Ti2Ni3Si/NiTi intermetallic alloys

Corrosion and wear resistant Ti2Ni3Si/NiTi intermetallic alloys with Ti2Ni3Si as the reinforcing phase and the ductile NiTi as the toughening phase were designed and fabricated by the laser melt-deposition manufacturing process. Electrochemical behavior of the alloys was investigated using potentiodynamic polarization testing and electrochemical impedance spectroscopy in an NaOH solution. The results showed that the alloys have outstanding corrosion resistance due to the formation of a protective passive surface film of Ni(OH)2 as well as the high chemical stability and strong inter-atomic bonds inherent to Ti2Ni3Si and NiTi intermetallics. The Ti2Ni3Si content has a significant influence on the microstructure of the alloys but only a slight effect on electrochemical corrosion properties.