The following is a comparison of the corrosion res

The following is a comparison of the corrosion resistance of TB2 titanium alloy and TC4 titanium alloy:

Characteristics of Passivation Films

• TB2 Titanium Alloy: An oxide film can form on its surface to play a role in corrosion prevention. In a conventional environment, this oxide film can provide relatively good protection, but there is relatively less research and data compared to TC4 titanium alloy.

• TC4 Titanium Alloy: A dense TiO₂ passivation film with a thickness of about 2 - 5 nanometers can spontaneously form on its surface. This film has good stability and regeneration ability. Even if it is mechanically damaged, it can quickly regenerate to continuously provide protection.

Corrosion Resistance in Different Media

• TB2 Titanium Alloy: In high-chloride aqueous solutions and chloride corrosion environments, its abilities to resist chloride pitting corrosion, crevice corrosion, and stress corrosion are far better than those of ZCuSn10Pb5, NiASH840, W.Nr.1.4547, a series of soft magnetic alloys, and NS332 Invar alloys. It exhibits good corrosion-resistant characteristics in various severe corrosion environments.

• TC4 Titanium Alloy: It shows an extremely low corrosion rate in chloride solutions, usually less than 0.005 mm/a. In strongly corrosive environments such as sulfuric acid, phosphoric acid, and hydrofluoric acid, its corrosion rate is also much lower than that of other common metal materials like stainless steel and aluminum alloys.

Influence of Temperature and pH Value on Corrosion Resistance

• TB2 Titanium Alloy: It still has relatively good carburization resistance when working for a long time below 452 °C. However, there is relatively little detailed research on the changes in the stability and corrosion resistance of its passivation film under different pH values and high-temperature conditions.

• TC4 Titanium Alloy: When the temperature rises above 100 °C, the formation rate and stability of the passivation film will decline. Under strongly acidic conditions with a pH value lower than 2, the dissolution rate of the alloy's passivation film increases significantly.

Corrosion Resistance When in Contact with Other Metals

• TB2 Titanium Alloy: When it is in contact with aluminum alloys and structural steels, the alloy itself does not corrode, but the dissimilar metals are corroded. After anodization, it can slow down the corrosion speed of the structural steel and aluminum alloys in contact with it.

• TC4 Titanium Alloy: When it is in contact with other metals, it may accelerate the dissolution of the metal acting as the anode due to galvanic corrosion. For example, during the contact with 90/10 Cu-Ni alloy, both the galvanic current density and the natural corrosion current density increase, resulting in a significant increase in the total corrosion rate.