Corrosion behavior of laser melting-deposited γ/Mo₂Ni₃Si metal silicide alloy

The corrosion behavior of Laser melting-deposited γ/Mo₂Ni₃Si alloy consisting of Mo₂Ni₃Si primary dendrites and Mo₂Ni₃Si/γ eutectic matrix in different mediums were investigated by polarization curve, Tafel Plot, EIS and immersion corrosion. Results showed that the alloy has excellent corrosion resistance in NaOH solution of 1 mol/L owing to the formation of stable passivation film. Unstable passivation film was formed in H₂SO₄ solution of 1 mol/L. No passivation occurred in neutral or acid solutions containing Cl^-. The alloy exhibited very poor corrosion resistance during the immersion test in HCl solution of 1 mol/L due to the preverential phase-boundary corrosion by Cl^-.