Effect of the Microstructure of Ti-5Mo on the Anodic Dissolution in H₂SO₄⁽¹⁾ Available to Purchase

The effect of microstructure of the Ti-5Mo alloy on its anodic dissolution rate in sulfuric acid solution at various temperatures has been investigated. TiMo alloys exhibit a region of increased dissolution rate in the vicinity of +0.20 V [saturated calomel electrode (SCE)] in 10% H₂SO₄, the same potential region in which pure Mo exhibits a large anodic dissolution rate. Aging of Ti-5Mo at 350 C was found to lead to the formation of ω phase. Heat treatment caused larger passive currents in 10% H₂SO₄, but the critical passivation potentials and corrosion potentials were not significantly affected. Molybdenum was enriched in the oxide formed on aged Ti-5Mo at +0.23 V (SCE), in comparison with the Mo concentration found in the oxide on as-received Ti-5Mo. Combined with literature data, these results indicate that the larger passive current of the aged alloy arises from the poorly protective character of the Mo-rich oxide that forms from the Mo-enriched β phase generated by the aging treatment.