HOT CORROSION BEHAVIOR OF Co- AND Ni-BASED ALUMINIDE COATINGS

摘要

This study compares and ranks the low-temperature (Ⅰ.e., 705oC/1300oF) hot corrosion resistance of CoCrAlY and Pt-modified CoAl coatings, together with Pt-modified β-NiAl coatings. A laboratoryscale Dean rig was used to simulate the hot corrosion conditions. Coating performances under the low- temperature (Type Ⅱ) conditions were ranked by assessing the cross-sectional SEM images of the corroded samples. It was found that the CoCrAlY coating had better resistance than the Pt-modified CoAl coating for the range of times tested (up to 200 h), while the Pt-modified β-NiAl coating had the best resistance overall.