Alloy degradation under oxidizing-sulfidizing conditions at elevated temperatures

• Main Author: Brian Gleeson
• Format: Article
• Language: English
• Published: Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímeros (ABPol) 2004-03-01
• Series: Materials Research
• Subjects: sulfidation; thermodynamics; kinetic boundary; breakaway; critical microstructure
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392004000100010

Exposure of high-temperature alloys to a low-P O2 oxidizing-sulfidizing environment above about 550 °C is often characterized by an initial period of protective oxidation followed by more rapid corrosion. This paper will provide a brief overview of alloy corrosion in oxidizing-sulfidizing atmospheres, 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. The paper will conclude with a specific example of alloy development for the filtration of hot oxidizing-sulfidizing gases.