Corrosion resistance of TA9 titanium rods in various corrosive environments

TA9 is an alpha titanium alloy with similar technological and mechanical properties to 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 content of Pd is further increased, and the corrosion rate of the alloy is almost unchanged, and when the content of Pd is lower than 0.05%, the corrosion rate increases. 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 it is more suitable to use Ti-0.2Pd.

The data show that the corrosion resistance of Ti-0.2Pd in reducing medium is obviously better than that of industrial pure titanium, and the corrosion resistance of the welding zone of Ti-0.2Pd is the same as that of the base material. The stabilization potential of Ti-0.2Pd in air-filled hydrochloric acid is significantly positive compared with that in deaerated hydrochloric acid, and the corrosion rate can be reduced by 10 times. However, in argon-filled or nitrogen-filled acid solution, the passivation performance of Ti-0.2Pd decreases significantly when the new corrosion solution is constantly replaced or the volume of the solution per unit area of the sample increases. Therefore, it should be avoided to use a small amount of palladium in Ti-0.2Pd.TA9 titanium alloy in the complete absence of oxygen or oxidant, which improves the corrosion resistance in oxidizing media, especially the resistance to crevice corrosion. Therefore, it is widely used in hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and chloride corrosion media.