Summary of studies on hot corrosion of iron-based alloys by sodium sulfate in O2/SO2/SO3 environment

Overview & Synopsis

Iron base heat-resistant alloys are widely used in high temperature environments, especially in civil and industrial boilers and other combustors. This type of alloys was found to undergo hot corrosion when covered with a sulfate deposit. Recent studies of sulfate-deposit-induced hot corrosion of iron-base alloys are selectively reviewed in this paper. Emphasis is placed on studies of the hot corrosion occurring at relatively low temperatures, concerning the thermodynamics of the formation of liquid sulfate eutectics, the corrosion behavior of various iron-base alloys, and an electrochemical mechanism proposed by the present authors. In addition, electrochemical measurements for the evaluation of hot corrosion resistance of iron-base alloys are briefly reported. Some coatings were prepared and their performance in hot corrosion environments is included in this paper.