Originally Posted by
atakacs
Not a metallurgist by any means but I thought that sulfidation was actually a desired process?
No, it's exactly the opposite, sulfidation is bad, nasty stuff. Unlike oxidation in aluminum that provides a protective coating and longer life, sulfidation in superalloys shortens life causing premature cracking and component failure. Protective coatings have been devised to guard against sulfidation, but there are other factors that contribute to premature sulfidation failures in turbine blades and vanes. Here is a photo of sufidation attack on a superalloy where a crack has developed. Add stress and cycles to the equation and the component will crack and fail prematurely...
