A review of recent studies of the role of zinc as an inhibitor of hot corrosion from molten sulphates

✍ Scribed by P.J. Hancock; H.A. Hancock; W.F. Caley; R.S. Hollingshead

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 481 KB
• Volume: 120-121
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(89)90756-9

✦ Synopsis

Hot corrosion of metals in the temperature range 700-900 °C is caused by the presence of sulphate deposits on the surface formed from the reaction between sea salt and sulphur trioxide in marine turbine engines. This paper reviews investigations of the effects of adding zinc in order to inhibit this form of corrosion.

The presence of zinc in the salt deposits served to modify the rate of hot corrosion significantly. Its role has been studied with respect to the acid-base fluxing theory and in the presence of excess NaCI. The zinc reduced the ability of the corrosive salt mixtures to dissolve the protective oxide layers on the alloys and also lowered the electrochemical potential of the corrosion reaction itself.