Since titanium metal first became a commercial reality in 1950, corrosion resistance has been an important consideration in its selection as an engineering structural material. Titanium has gained acceptance in many media where its corrosion resistance and engineering properties have provided the corrosion and design engineer with a reliable and economic material.
Fresh Water Corrosion – Steam
Titanium resists all forms of corrosive attack by fresh water and steam to temperatures in excess of 600°F (316°C). The corrosion rate is very low or a slight weight gain is experienced. Titanium surfaces are likely to acquire a tarnished appearance in hot water steam but will be free of corrosion.
Some natural river waters contain manganese which deposits as manganese dioxide on heat exchanger surfaces. Chlorination treatments used to control sliming results in severe pitting and crevice corrosion on stainless steel surfaces. Titanium is immune to this form of corrosion and is an ideal material for handling all natural waters.
Seawater General Corrosion
Titanium resists corrosion by seawater to temperatures as high as 500°F (260°C). Titanium tubing, exposed for 16 years to polluted seawater in a surface condenser, was slightly discolored but showed no evidence of corrosion. Titanium has provided over thirty years of trouble-free seawater service for the chemical, oil refining and desalination industries.
Exposure of titanium for many years to depths of over a mile below the ocean surface has not produced any measurable corrosion. Pitting and crevice corrosion are totally absent, even if marine deposits form. The presence of sulfides in seawater does not affect the resistance of titanium to corrosion. Exposure of titanium to marine atmospheres or splash or tide zone does not cause corrosion.
Titanium has the ability to resist erosion by high velocity seawater. Velocities as high as 120 ft./sec. cause only a minimal rise in erosion rate. The presence of abrasive particles, such as sand, has only a small effect on the corrosion resistance of titanium under conditions that are extremely detrimental to copper and aluminum base alloys. Titanium is considered one of the best cavitation resistant materials available for seawater service.