Corrosion resistance characteristics of titanium material

Titanium is a metal with a strong passivation tendency, which can quickly generate a stable oxidation protective film in the air and oxidation or neutral aqueous solution, even if the film is damaged for some reason, it can also quickly and automatically recover. 

Due to the great passivation properties of titanium, the corrosion, and it may not be accelerated when contacted with different metals, in many cases. If in low concentrations of non-oxidized acid, if the Pb, Sn, Cu or Monel alloy is in contact with titanium to form an electric couple, these materials corrosion is accelerated, and titanium is not affected. In hydrochloric acid, when titanium contacts with low-carbon steel, the new hydrogen produced on the surface of titanium destroys the oxide film of titanium, which not only causes the hydrogen fragility of titanium, but also accelerates the corrosion of titanium, which may be due to the high activity of titanium on hydrogen.

The iron content in titanium has an impact on the corrosion resistance in some media. In addition to the reasons of raw materials, the reason of the iron increase is often that the stained iron seeps into the welding duct, so that the local iron content in the welding duct increases, and then the corrosion has uneven properties. When using the iron parts to support the titanium equipment, the iron contamination on the iron-titanium contact surface almost inevitably accelerates the corrosion in the iron contamination area, especially in the presence of hydrogen. When the titanium oxide film on the stained surface is mechanically damaged, the hydrogen seeps into the metal. According to the temperature, pressure and other conditions, the hydrogen occurs the corresponding diffusion, which makes the titanium produce different degrees of hydrogen brittle. Therefore, titanium is used in medium temperature and medium pressure and hydrogen-containing systems to avoid surface iron contamination.

Titanium also has corrosion resistance and fatigue stability.

Titanium has good gap corrosion resistance, especially Ti-0.3Mo-0.8Ni and Ti-0.2Pd alloys, so Ti-0.3Mo-0.8Ni and Ti-0.2Pd alloys are widely used in the sealing surface materials of container equipment, to solve the gap corrosion problem of equipment sealing surface.