This title appears in the Scientific Report :
2018
Please use the identifier:
http://dx.doi.org/10.1080/09603409.2017.1389422 in citations.
Effect of test atmosphere composition on high-temperature oxidation behaviour of CoNiCrAlY coatings produced from conventional and ODS powders
Effect of test atmosphere composition on high-temperature oxidation behaviour of CoNiCrAlY coatings produced from conventional and ODS powders
The oxidation behaviour of free-standing CoNiCrAlY coatings produced by low-pressure plasma spraying using conventional powder and oxide dispersion strengthened (ODS) powder containing 2 wt. % Al-oxide dispersion was investigated. Thermogravimetric experiments at 1100 °C in Ar-20%O2 and Ar-4%H2-2%H2...
Saved in:
Personal Name(s): | Huang, T. (Corresponding author) |
---|---|
Bergholz, J. / Mauer, G. / Vassen, R. / Naumenko, D. / Quadakkers, W. J. | |
Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEK-1 Werkstoffstruktur und -eigenschaften; IEK-2 |
Published in: | Materials at high temperatures, 35 (2018) 1-3, S. 97 - 107 |
Imprint: |
Amsterdam [u.a.]
Elsevier Science
2018
|
DOI: |
10.1080/09603409.2017.1389422 |
Document Type: |
Journal Article |
Research Program: |
Methods and Concepts for Material Development |
Publikationsportal JuSER |
The oxidation behaviour of free-standing CoNiCrAlY coatings produced by low-pressure plasma spraying using conventional powder and oxide dispersion strengthened (ODS) powder containing 2 wt. % Al-oxide dispersion was investigated. Thermogravimetric experiments at 1100 °C in Ar-20%O2 and Ar-4%H2-2%H2O showed lower oxidation rates of the ODS than the conventional coating. In the latter material the scale growth was enhanced by extensive Y-incorporation of Y/Al-mixed oxide precipitates in the scale and apparently by Y-segregation to oxide grain boundaries. In the ODS coating the alumina dispersion bonded Y in the form of Y-aluminate thereby effectively suppressing scale ‘overdoping’. SEM/EBSD studies of all alumina scales revealed a columnar grain structure with the lateral grain size increasing approximately linearly with depth from the oxide/gas interface. For both coatings the alumina scale growth was slower in Ar–H2–H2O than in Ar–O2. The result is believed to be related to a lower oxygen potential gradient and to slower grain boundary diffusion in the scale forming in H2/H2O containing gas. |