Coating steel or other metal surfaces with a less noble metal sets up a cathodic protection circuit. The metal surface becomes the cathode and the aluminium or zinc becomes the sacrificial anode. Moisture from the atmosphere, condensation, or submersion becomes the electrolyte to complete the electrochemical cell. Cathodic protection systems are commonly used to protect steel structures, pipelines, storage tanks, pier piles, oil platforms, ship hulls, etc. In some cases, cathodic protection can be an effective method of preventing stress corrosion cracking. The TSA process deposits the less noble metal directly onto the surface of the metal to be protected.
Sacrificial thermal spray coatings provide much better corrosion resistance than paint or numerous other coatings, especially in cases where there is porosity or when the coating is breached. In seawater, the surrounding coating will even protect large cuts or breaches where steel is exposed. This makes TSA the coating of choice for corrosion under insulation (CUI) and areas where temperature extremes will not allow the use of common paints and sealers.
