Corrosion resistance of titanium grade 7 alloy rods in a variety of corrosive environments!

Titanium grade 7 alloy is an α 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 decreases significantly, and the further increase of Pd content makes the corrosion rate of the alloy almost unchanged. However, when the content of Pd is lower than 0.05%, the corrosion rate increases. When the acid concentration is low, the titanium and 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. Compared with deaerated in air-filled hydrochloric acid, the stabilization potential of Ti-0.2Pd is significantly positive, 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 obviously when the volume of the solution of the sample per unit area increases. Therefore, it is necessary to avoid adding a small amount of palladium into Ti-0.2Pd. titanium grade 7 alloy in the condition of 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.