Fireside Corrosion Behaviors of Inconel 740H Superalloy in Various SO_2 Contents

摘要

Fireside corrosion behavior of Inconel 740H superalloy was studied at 750°C in simulated coal ash/flue gas environments by means of XRD, SEM and EDS. The results indicated that the corrosion behavior was strongly related to the SO_2 levels and was significantly affected by NaCl additions. In presence of the atmospheres with 0.1%SO_2, the alloy exhibited the highest corrosion resistance due to formation of a stable and dense Cr_2O_3 film. In present of the atmosphere with 1.5%SO_2, however, a non-coherent and porous Cr_2O_3 film was formed. The thickness of film and internal sulfides were substantially increased. The mechanism of ash corrosion formation was also discussed.