Factors controlling corrosion in high-temperature aqueous solutions: a contribution to the dissociation and solubility data influencing corrosion processes

Typical materials for applications in high-temperature, high-pressure aqueo us solutions are stainless steels, nickel-base alloys, titanium, tantalum, noble metals, or ceramics. Under these conditions, these materials are ofte n severely attacked, especially in the presence of acids, salts, or gases. Corrosion phenomena in high-temperature aqueous solutions are mainly influe nced by the following factors: dissociation of acids, salts, and bases, the solubility of gases, the solubilities of corrosion products, and the stabi lity of the protecting oxide layers. The influences of these factors on the corrosion, together with literature data of dissociation constants and sol ubilities of oxides, are reviewed in this paper. A recommendation is given for the application of possible reactor materials for oxidizing high-temper ature aqueous systems in the presence of different inorganic species. (C) 1 999 Elsevier Science B.V. All rights reserved.