抄録
The effect of alloying elements, Fe, Co, Ni, Cr, Mn, Sn, Al, Nb, Ta, V, and Zr, at additions of 1, 3, and 5wt%, has been determined on the corrosion of Ti-Mo alloys by the steeping test, measurement of anodic polarization characteristics, and observation of the test piece surfaces after the steeping test. Addition of Nb, Ta, V, or Zr to the Ti-15Mo base alloy produced the alloys highly resistant to boiling HCl. Preferential attack at the grain boundaries was not observed with the Ti-15Mo-5Nb alloy; the type of corrosion was general corrosion. Corrosion resistance of Ti-15 Mo binary alloys, however, was found to be lower than that of the Ti-15 Mo binary alloys. Polarization curves for the highly corrosion resistant Ti-15 Mo base ternary alloys, containing Zr, Nb, V, or Ta as an alloying element, indicate that the passivation potential decreases in the order of Zr, Nb, Ta, and V. The maximum potential value was obtained at an addition of 1wt% of each alloying element. The secondary passivation range was observed in the polarization curves for all alloys tested, but the effect of the alloying elements was not recognized.
