Corrosion behaviour of a new Ti-6Al-2Nb-1Ta alloy in various solutions

✍ Scribed by C. Pirvu; I. Demetrescu; P. Drob; E. Vasilescu; S. Ivanescu; M. Mindroiu; C. Vasilescu; S. I. Drob

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: German
• Weight: 462 KB
• Volume: 62
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.201006041

✦ Synopsis

Abstract

A new Ti‐6Al‐2Nb‐1Ta alloy was obtained for to satisfy the mechanical and anticorrosion requirements in neutral corrosive environment. The corrosion behaviour of this new Ti‐6Al‐2Nb‐1Ta alloy in 0.1 M Na~2~SO~4~, 3% NaCl solutions and synthetic sea water was studied in this paper, using potentiodynamic and linear polarisation method, electrochemical impedance spectroscopy (EIS) and monitoring of the open circuit potentials. The structure of the alloy represents an α + β uniform structure with un‐oriented grains. From the potentiodynamic polarisation curves it resulted that the studied alloy is self‐passivated in all three solutions having a very good and very easy tendency to passivation. The most favourable values of the electrochemical parameters were registered in 0.1 M Na~2~SO~4~ solution due to its reduced corrosivity. EIS measurements proved the improvement of the passive layer resistance with the immersion time. An electric equivalent circuit with two time constants was fitted. The values of the polarisation resistances showed very good protective capacities which improved in time. The open circuit potentials have the general tendency to ennoble in time, suggesting the thickening of the passive films and the increase of their protective capacities.