High-Temperature Oxidation-Sulfidation: An Abridged Overview and Application to Alloy Selection for Hot-Gas Filtration

摘要

Exposure of high-temperature alloys to low-P_(O_2) oxidizing- sulfidizing environments above about 550℃ is often characterized by an initial period of protective oxidation followed by more rapid corrosion. This paper will provide a brief overview of corrosion in oxidizing-sulfidizing environments, with specific consideration given to the thermodynamic and kinetic aspects of the process, resulting modes of degradation, and alloy selection. The concept of a "critical microstructure" in the subsurface of the alloy as a prerequisite to initiating protective scale breakdown will also be discussed. This is a concept that was originally postulated by Choi and Stringer, and represents one of many contributions by John Stringer to the area of high-temperature degradation. This paper will conclude with a specific example of alloy development for hot-gas filtration under oxidizing-sulfidizing conditions.