The combined effect of refractory coatings containing reactive elements on high temperature oxidation behavior of chromia-forming alloys

被引:16
作者
Chevalier, S
Bonnet, G
Larpin, JP
Colson, JC
机构
[1] Univ Bourgogne, UMR 5613 CNRS, Lab Rech React Solides, F-21078 Dijon, France
[2] Univ La Rochelle, Lab Etud Mat Milieux Agressifs, F-17042 La Rochelle 01, France
关键词
MOCVD coatings; Al2O3; Cr2O3; Nd2O3; SM2O3; codeposition; isothermal and cyclic oxidation; reactive element effect;
D O I
10.1016/S0010-938X(03)00017-9
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
The high temperature oxidation behaviors of chromia-forming alloys (F17Ti and Fe-30Cr alloys) have been studied at 1273 K under isothermal conditions and at 1223 K under cyclic conditions, in air under the atmospheric pressure. To extend the oxidation lifetime, coatings have been applied onto the alloy surfaces. Al2O3 and Cr2O3 films doped with SM2O3 or Nd2O3 were prepared via the metal-organic chemical vapor deposition technique. Single Cr2O3, Al2O3, Nd2O3 and codeposited Cr2O3-Nd2O3, Al2O3-Nd2O3, Al2O3-SM2O3 coatings drastically improved the chromia-forming alloy high temperature oxidation behavior, since they decreased the oxidation rate and enhanced the oxide scale adhesion. Results showed that a critical amount of reactive element (Nd or Sm) in chromia or alumina coatings (11-18 at.%) was needed to observe the most effective effect. The fast precipitation of NdCrO3 or NdTi21O38 and the segregation of reactive elements at the chromia grain boundaries slowing down outward cation transport and consequently blocking the chromia grain growth, was supposed to be the main reasons of the beneficial effect ascribed to the reactive elements in chromia scales. (C) 2003 Elsevier Science Ltd. All rights reserved.
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页码:1661 / 1673
页数:13
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