CP-Ti在含氟离子硝酸中表面附着物形成研究

Titanium has excellent corrosion resistance and can be used for long-term operation in boiling high concentration nitric acid medium. It is an ideal material for reprocessing equipment. The white attachment of the surface of CP-Ti in nitric acid with fluorine ion were analyzed by SEM, EDS, XRD and XPS characterization methods and its formation mechanism was explained. The results show that when the concentration of fluorine ions is below 50 µL/L, the corrosion rate of CP-Ti decreases and then tends to be stable gradually. When the concentration of fluorine ions is 50 µL/L and above, the corrosion rate decreases first and then increases, presenting a "v" pattern. The phase of the white attachment on the CP-Ti surface is TiO₂. The formation mechanism of the attachment is divided into two steps: firstly, the porous film forms on the surface of the CP-Ti; secondly, TiO₂ is grown with the pore of porous film as the base point and then falls.