The corrosion resistance of TA9 titanium rods in various corrosive environments

TA9 is an alpha titanium alloy, and its process performance and mechanical properties are similar to those of industrial pure titanium. When the content of Pd added to titanium reaches 0.1%-0.2%, the corrosion rate of titanium in sulfuric acid and hydrochloric acid is significantly reduced. Further increasing the content of Pd, the corrosion rate of the alloy remains almost unchanged, while when the Pd content is lower than 0.05%, the corrosion rate increases instead. At low acid concentrations, the titanium-palladium alloy containing 0.13% Pd already has satisfactory corrosion resistance, but when the acid concentration is high, Ti-0.2Pd has better corrosion resistance, so Ti-0.2Pd is more suitable.

The data shows that Ti-0.2Pd has significantly better corrosion resistance in reducing media than industrial pure titanium, and the weld zone of Ti-0.2Pd has the same corrosion resistance as the base material. Compared with the air-free hydrochloric acid, Ti-0.2Pd in the air-filled hydrochloric acid has a significantly positive shift in the stable potential and the corrosion rate can be reduced by 10 times. However, in the acid solution filled with argon or nitrogen, when the new corrosion solution is constantly replaced or the volume of the solution on the unit area of the sample increases, the passivation performance of Ti-0.2Pd significantly decreases. Therefore, Ti-0.2Pd should not be used in completely oxygen-free or oxidant-free conditions. Adding a small amount of palladium to TA9 titanium alloy improves its corrosion resistance in oxidizing media, especially its ability to resist crevice corrosion. Therefore, it is widely used in hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and chloride-containing corrosion media.