Microstructure and corrosion properties of laser-melted deposited Ti₂Ni₃Si/NiTi intermetallic alloy

Ti₂Ni₃Si/NiTi intermetallic alloy consisting of Ti₂Ni₃Si primary dendrites and Ti₂Ni₃Si/NiTi eutectic matrix was fabricated by the laser melting deposition manufacturing process. Corrosion behavior of the alloy was investigated under anodic polarization and immersion corrosion test conditions in NaCl, H₂SO₄ and NaOH solutions. Results showed that alloy has outstanding corrosion-resistance, characterized by its wide passivation region and low passive anodic current density during the anodic polarization and low immersion corrosion rates. The excellent corrosion resistant properties of the alloy is attributed to the formation of a protective passive surface film as well as the high chemical stability and strong inter-atomic bonds inherent to Ti₂Ni₃Si and NiTi intermetallic.