中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 17 Special 1 November 2007 |
ZHAO Qiong(趙 瓊)1, BAI Ling-yun(白凌云)1
（1. School of Materials Science and Engineering, Jiangxi Science and Technology Normal University,
Nanchang 330013, China;
2. Key Laboratory of Nuclear Resources and Environment (East China Institute of Technology),
Ministry of Education, Nanchang 330013, China）
Abstract:The corrosion behavior of ternary Fe-15Cu-5Al (mole fraction, %) alloy was studied at 1 000 ℃ in 0.1 MPa pure oxygen. The Fe-rich alloy shows two parabolic oxidation stages, with a small increase of the parabolic rate constant from 1.9×10−9 to 4.1×10−9 g2/(cm4∙s). The scale grown on the alloy is very complicated, with formation of overgrown nodules interspersed among bulky stratified scales. The nodules and the bulky stratified scales are always composed of an outer layer of CuFe2O4 and of an inner layer containing Fe2O3 and Fe3O4. Beneath the external scale of the nodules, there is an internal oxidation zone where iron oxide is mixed with copper metal. Furthermore, the base of the internal oxidation zone is characterized by a discontinuous aluminum-enriched layer of either Al2O3 or FeAl2O4. For the stratified scales, no internal oxidation zone is present beneath the innermost Al2O3 or FeAl2O4 layer. Aluminum depletion is present in advance of the internal oxidation front, while iron depletion is not observed. The corrosion feature of the ternary Fe-15Cu-5Al alloy is partly associated with that of the corresponding binary Fe-Cu and Fe-Al alloys. The peculiar scale microstructure observed is considered mainly as a consequence of the limited solubility of the iron and copper components in one another and of the monovariant system of the ternary Fe-15Cu-5Al alloy.
Key words: Fe-15Cu-5Al alloy; ternary alloy; corrosion behavior; nodules
