Effect of pre-oxidation on coke formation and metal dusting of electroplated Ni3Al–CeO2-based coatings in CO–H2–H2O
✍ Scribed by H. Liu; W. Chen
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- German
- Weight
- 441 KB
- Volume
- 59
- Category
- Article
- ISSN
- 0947-5117
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✦ Synopsis
Abstract
Pre‐oxidation was introduced to improve the resistance of electroplated pure, 5 µm CeO~2~‐dispersed, and 9–15 nm CeO~2~‐dispersed Ni~3~Al coatings to coke formation and metal dusting in 24.4%CO–73.3%H~2~–2.3%H~2~O at 650 °C. Coke formation and metal dusting of pre‐oxidized Ni~3~Al‐based coatings were retarded up to 200 h owing to a thin Al~2~O~3~ scale induced during pre‐oxidation. The long‐term effectiveness of pre‐oxidation nonetheless depended on the integrity of Al~2~O~3~ scale. The pure Ni~3~Al coating suffered severe spallation after pre‐oxidation and thereby showed the worst long‐term resistance. Two pre‐treated 9–15 nm CeO~2~‐dispersed Ni~3~Al coatings exhibited the best long‐term resistance to carbon attack because nano‐CeO~2~ particles maintained a full coverage of Al~2~O~3~ scale on the coatings. Two 5 µm CeO~2~‐dispersed Ni~3~Al coatings showed significant spallation after pre‐oxidation because of an overdoping effect and experienced coke formation and metal dusting during long‐term exposure.