Generally speaking, titanium tubes have better corrosion resistance in oxidizing media (such as nitric acid, chromic acid, hypochlorous acid and perchloric acid, etc.).
In reducing acid (such as dilute sulfuric acid solution, hydrochloric acid solution, etc.), because the passivation of the oxide film is destroyed, the corrosion rate is relatively fast, and it increases with the increase of temperature and concentration. In reducing acids, the addition of heavy metal salts can play a significant role in corrosion inhibition.
The corrosion resistance of titanium-palladium alloy and titanium-nickel-molybdenum alloy is much higher than that of industrial pure titanium.
Titanium tube is the best metal material for heating equipment of nitric acid solution. The titanium heat exchanger is subjected to 60% nitric acid at about 193°C, and no corrosion has been found after many years of use.
In the boiling 40% and 68% nitric acid, some corrosion began to occur. After a short period of time, the passiveness of titanium recovered and the corrosion rate was significantly reduced. It may be related to the corrosion inhibition effect of titanium ions.