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Effect of atmosphere composition on the oxidation behavior of MCrAlY coatings
Author(s) -
Song P.,
Subanovic M.,
Toscano J.,
Naumenko D.,
Quadakkers W. J.
Publication year - 2011
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201005851
Subject(s) - atmosphere (unit) , isothermal process , materials science , composition (language) , oxide , metallurgy , meteorology , thermodynamics , geography , physics , linguistics , philosophy
In the present work the effect of atmosphere composition on the growth rate and adherence of the alumina scales was studied using free‐standing MCrAlY‐coatings and TBC‐specimens with MCrAlY‐bondcoats. The exposures comprised isothermal and cyclic exposures in laboratory air and Ar‐H 2 ‐H 2 O at 1100 °C. It is shown that minor Zr‐addition to the bondcoat results in enhanced scale growth and internal oxidation. This effect is independent of the atmosphere composition. As a consequence of the rapid oxide formation the times to TBC failure on the Zr‐containing bondcoat in both atmospheres were much shorter compared to those with Zr‐free bondcoat. In the latter case the formation of a thin compact alumina TGO was slower in H 2 /H 2 O than in air resulting in significantly longer TBC‐lifetime in the former atmosphere.