Titanium is a metal with strong passivation. In the air, oxidizing condition or neutral aqueous solutions, a stable protective oxide film can be formed rapidly. Even if the film is damaged for some reasons, it can automatically restore. Therefore, titanium has excellent corrosion resistance in oxidizing and neutral medium.
Because of titanium's huge passivating performance, in many cases, it can prevent titanium from accelerating corrosion when contacting with heterogeneous metals, but the contacting may accelerate the corrosion of heterogeneous metals. For example, in low concentration of non-oxidizing acid, when people make Pb, Sn, Cu or Monel alloy contact with titanium to form an electric couple, the corrosion of these materials is accelerated, while titanium is not affected. While in hydrochloric acid, when people touch titanium with low carbon steel, it will destroys the titanium oxide film due to the production of new hydrogen on the surface of titanium, which not only causes the hydrogen embrittlement of titanium, but also accelerates the corrosion of titanium. Bango Alloy professionals thinks that it may be caused by the high activity of titanium on hydrogen.
The iron content in titanium has an influence on the corrosion resistance of some media. Besides the influence of raw materials, the increase of iron is often caused by the infiltration of the Contamination of the iron during welding, which increases the iron content of parts of the weld bead. In that condition, the corrosion is uneven. It is almost inevitable that iron contamination on the titanium contact surface will accelerate in the iron contamination area, especially in the presence of hydrogen.
When the titanium oxide film on the stained surface is mechanically damaged, hydrogen permeates the metal, and diffuses accordingly according to temperature, pressure and other conditions, which makes titanium produce different degrees of hydrogen embrittlement. So titanium is used at medium temperature and pressure and in hydrogen bearing systems to avoid surface iron contamination.
When the titanium oxide film on the stained surface is mechanically damaged, hydrogen permeates the metal, and it will diffuses according to temperature, pressure and other conditions, which makes titanium produce different degrees of hydrogen embrittlement. Therefore, titanium should avoid surface iron pollution when used in medium temperature, medium pressure and hydrogen bearing system.
1. In general, titanium will not undergo hole erosion.
2. Titanium is corrosion resistant and stable.
3. Titanium has good corrosion resistance, especially ti-0.3 mo-0.8 Ni and ti-0.2 Pd alloys. Therefore, ti-0.3 mo-0.8 Ni and ti-0.2 Pd alloys are widely used in sealing surface materials of container equipment to solve the problem of gap corrosion on sealing surface of equipment.
