2005, Volume 8, Issue 15+16
Corrosion Resistance of Titanium and Some Ternary Titanium Alloys in Acid Environments from Chemical Industry
1 Institute of Physical Chemistry "I. G. Murgulescu", Bucharest, Romania
2 ICSI - Rm. Valcea
3 Las Palmas de Gran Canaria University, Tafira, Spain
Corrosion resistance of titanium and its ternary Ti-0.8Ni-0.4Mo alloy (in the casting state and metallurgical working state by forging) in nitric acid solutions (20% and 60% concentrations at 25°, 50° and 75°), usually used in chemical industry, was studied. Both titanium and its Ti-0.8Ni-0.4Mo alloy are self-passivated in nitric acid solution; the open circuit potentials are very noble. This behaviour is due to the compact and protective titanium dioxide (TiO2) that is formed on the surface. The alloy passive potential range is narrower and the alloy passive cirrent density is higher than of the bae metal because of the dissolution of th alloying elements through the passive film. Corrosion rates revealed a good resistence of the titanium and titanium ternary Ti-0.8Ni-0.4Mo alloy. Forging alloy presents a better resistance that the casting alloy. Impedance spectra were modeled with an equivalent circuit with two time constants: the first constant is for passive film and the second for diffusion processes through this protective layer.
Ternary titanium alloy (casting and forging); nitric acid solutiona; EIS; corrosion rates; electrochemical parameters.
Tag search Ternary titanium alloy casting forging nitric acid solutiona EIS corrosion rates electrochemical parameters