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High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
SJR: 0.137 SNIP: 0.341 CiteScore™: 0.43

ISSN Druckformat: 1093-3611
ISSN Online: 1940-4360

High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes

DOI: 10.1615/HighTempMatProc.v4.i3.30
12 pages

ON THE OXIDATION OF Ni-23Co-17Cr-12AI-0.5Y-ALLOY SERVING AS BOND COAT IN THERMAL BARRIER COATINGS

Reidar Haugsrud
Centre for Materials Science Gaustadalleen 21,N-0371 Oslo, Norway
Ingard Kvernes
Kvernes Technology AS., Munkedamsveien 96,P-box 2806 Solli, N-0204 Oslo, Norway
Erick Lugscheider
Werkstoffwissenschaften Lehr und Forschungsgebeit der RWTH Jiilicher Sir. 342-352 52070 Aachen; Surface Engineering Institute (IOT), RWTH University of Technology Aachen, Augustinerbach 4-22, 52066 Aachen, Germany

ABSTRAKT

Specimens of air plasma sprayed thermal barrier coatings with a Ni-23Co-17Cr-12Al-0.5Y bond coat have been oxidised in air at 900°C for 300-3000 hours. The oxide scale formed between the ceramic and the bond coat consists of essentially pure AI2O3, except at the interface with the ceramic overlay, where the composition of the oxide reflects that of the bond coat. The oxidation rate decreases with time and reflects growth of AI2O3, through inward grain boundary diffusion of oxygen. An inter-metallic phase identified as NiAl, precipitated during high temperature exposure. The thickness of the inter-metallic zone decreased with increasing oxidation duration. This was interpreted to reflect diffusion of Al toward the oxide and into the substrate. The amount of transient oxides at the surface was found to depend on the surface topography.