Abstract
Abstract
The influence of exposure temperature on the cyclic oxidation behavior of simple and platinum aluminide coatings on various superalloy substrates was investigated. Coatings of ��-NiAl, ��-NiPtAl and ��-��' NiPtAl were tested and compared in dry oxygen at 1050 - 1150�aC. There was a clear influence of substrate sulfur content on the oxidation behavior of ��-NiAl coatings at all three temperatures. The impact of substrate impurities, especially S content, was significantly reduced for ��-NiPtAl coatings at all three temperatures. Simple ���{��' NiPtAl coatings showed excellent oxidation behavior up to 1100�aC on some alloys, but were more sensitive to substrate composition, especially Hf content, than were ��-NiPtAl coatings.
