Titanium will have slow reaction with dilute hydrochloric acid, but in the process of reaction will gradually form an oxide film to protect the metal titanium, so as to reduce the reaction. Another characteristic of titanium is the strong corrosion resistance, because of its special affinity to oxygen, it can produce a layer of dense oxide film on its surface, which can protect the titanium from medium corrosion. In most aqueous solution, metal titanium can produce purified oxide film on the surface. Therefore, in acidic, alkaline, neutral salt solution and oxidation medium, titanium has good stability, its corrosion resistance is better than conventional stainless steel and other non-ferrous metal, even it can be comparable with platinum. However, if in a certain medium, it can dissolve the oxide film on the surface of titanium in a row, the titanium in this medium will be corroded. For example, in hydrofluoric acid, concentrated or heat of hydrochloric acid, sulfuric acid and phosphoric acid, due to the solution can dissolve the oxide film on the surface of titanium, so titanium can be corroded. If the oxidizing agent or some metal ions are added to the solution, the oxide film on the surface of titanium is protected, and the stability of the titanium will be increased.
It can be known that titanium tube can not be used in hydrochloric acid, the premise is the normal atmospheric temperature and the dilute hydrochloric acid.
