"Turbine blades"
Question:
"I read your paper about hot corrosion of the gas turbine. But why are the blades (made of Rene 80) of the first stage high pressure turbine coated only with alluminide and not also with a ceramic overlay thermal barrier coating (that would have limited the corrosion and would have lowered the temperature of the blade)?"
Answer:
We had no knowledge of the thought process behind selection of the 1st-stage turbine blades. Cost may have been an issue. Also, it was apparent during the investigation that hot corrosion was a recognized deterioration mechanism and that the designers included fuel contamination limits and on-line water washes to minimize hot corrosion damage.