Corrosion resistance of Gr7 titanium rods in various corrosive environments
Gr7 is an α-titanium alloy, and its technological properties and mechanical properties are similar to those of industrial pure titanium. When the amount of Pd added to titanium reaches 0.1%-0.2%, the corrosion rate of titanium in sulfuric acid and hydrochloric acid is significantly reduced, and the Pd content is further increased, and the corrosion rate of the alloy is almost unchanged, and when the Pd content is less than 0.05% , The corrosion rate increases instead. When the acid concentration is low, the titanium-palladium alloy containing 0.13% Pd has satisfactory corrosion resistance, but when the acid concentration is high, Ti-0.2Pd has better corrosion resistance, so Ti-0.2Pd is more For appropriate.
The data shows that the corrosion resistance of Ti-0.2Pd in reducing media is significantly better than that of industrial pure titanium, and the welding zone of Ti-0.2Pd has the same corrosion resistance as the base material. Compared with de-aired hydrochloric acid in air-filled hydrochloric acid, Ti-0.2Pd has a significant positive shift of the stable potential, and the corrosion rate can be reduced by 10 times. However, in an acid solution filled with argon or nitrogen, new corrosion solutions or unit area tests are constantly replaced When the volume of the same solution increases, the passivation performance of Ti-0.2Pd is significantly reduced. Therefore, it should be avoided to use Ti-0.2Pd. Gr7 titanium alloy in the absence of oxygen or oxidizer. Adding a small amount of palladium to improve the oxidizing medium In the corrosion resistance, especially the ability to resist crevice corrosion. Therefore, it is widely used in corrosive media of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and chloride.
