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Titanium- Corrosion resistance to Waters

  • Fresh Water
  • Seawater

Fresh Water Steam
Titanium alloys are highly resistant to water, natural waters and steam to temperatures in excess of 300°C.

Excellent performance can be expected in high purity water, fresh water and body fluids. Typical contaminants found in natural water streams, such as iron and manganese oxides, sulfides, sulfates, carbonates and chlorides do not compromise titanium's performance. Titanium remains totally unaffected by chlorination treatments used to control biofouling.

Seawater
Titanium is fully resistant to natural seawater regardless of chemistry variations and pollution effects (i.e. sulfides, S2-).

Twenty year corrosion rates well below .01 mpy have been measured on titanium exposed beneath the sea, in marine atmospheres, and in splash or tidal zones. In the sea, titanium alloys are immune to all forms of localized corrosion, and withstand seawater impingement and flow velocities in excess of 100 ft/sec (0.0003 mm/y). Abrasion and cavitation resistance of these alloys is outstanding, explaining why titanium provides total reliability in many marine and naval applications. In addition, the fatigue strength and toughness of many titanium alloys are unaffected in seawater and lean titanium alloys are immune to seawater stress corrosion.

Titanium tubing has been used with great success for more than 20 years in seawater-cooled heat exchangers in the chemical, oil refining and desalination industries. The pH-temperature guidelines for crevice corrosion are generally applicable to seawater service as well.

When in contact with other metals, titanium alloys are not subject to galvanic corrosion in seawater. However, titanium may accelerate attack on active metals such as steel, aluminum, or copper alloys. The extent of galvanic corrosion will depend on many factors such as anode to cathode ratio, seawater velocity and seawater chemistry. The most successful strategies eliminate this galvanic couple by using more-resistant compatible, passive metals with titanium, all-titanium construction, or dielectric (insulating) joints. Other approaches for mitigating galvanic corrosion have also been effective: coatings, linings and cathodic protection.