In dilute hydrochloric acid, sulfuric acid and phosphoric acid, titanium dissolves much more slowly than iron. With the increase of concentration, especially when the temperature rises, the dissolution rate of titanium is significantly accelerated, and titanium dissolves quickly in the mixture of hydrofluoric acid and nitric acid.

Nitric acid is an oxidizing acid. Titanium in nitric acid can maintain a dense oxide film on its surface. With the increase of nitric acid concentration, this surface film presents various interference colors from yellowish, light yellow, yellowish brown to blue. The integrity of oxide film is a necessary condition to maintain the corrosion resistance of titanium. Therefore, titanium has excellent corrosion resistance in nitric acid. The corrosion rate of titanium increases with the temperature of nitric acid solution, and the temperature ranges from 190 to 230. C. When the concentration is between 20% and 70%, the corrosion rate can reach nearly 10mm/a. Is the corrosion rate of titanium in high temperature nitric acid.

However, adding a small amount of silicon containing compound into nitric acid solution can prevent the corrosion of high-temperature nitric acid on titanium. For example, after adding polysiloxane oil to 40% high-temperature nitric acid solution, the corrosion rate can be reduced to almost zero. There is also information, at 500. Below C, titanium has high corrosion resistance in 40%~80% nitric acid solution and steam. On the contrary, the addition of phosphide in nitric acid will accelerate the corrosion of titanium, which can be used to prepare its pickling solution. In fuming nitric acid, when the carbon dioxide content is more than 2%, strong exothermic reaction will be caused due to insufficient water content. The possibility of reaction between titanium and nitric acid is related to the content of N02 and water in nitric acid.

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