CORROSION BEHAVIOUR IN NEUTRAL ENVIRONMENT OF SOME TERNARY TITANIUM ALLOY

The purpose of this paper is to determine the effect of the alloying elements on the passive film formation on the Ti-Mo-Ni alloy, in concentrated chloride solutions, at high temperatures. The alloying of titanium with molybdenum and nickel has the following effects on the passivity behaviour of ternary Ti-0.5Mo-1Ni alloy: the shifting in noble direction of the alloy corrosion potential due to the couple galvanic effect of the molybdenum and nickel; the enlargement of the alloy passive potential range, as result of the molybdenum and nickel participation with its insoluble compounds at the consolidation of the alloy passive film; the decrease of the alloy passive current densities because of the same consolidation effect of the passive layer; both the titanium and Ti-0.5Mo-1Ni alloy do not present pitting corrosion; the decrease of the alloy corrosion rates in concentrated chloride solutions, in comparison with base metal.