用离子背散射和慢正电子束研究了活性元素Y和Ce对Fe-25Cr—40Ni合金在高温初期氧化动力学、氧化膜表层成份和微观缺陷结构的影响,实验结果表明了微量活性元素(≥0.05％)在高温氧化初期显著减少了合金的氧化速率,有效地促进了Cr_2O_3的生长,抑制了Fe和Ni氧化物的形成,改善了氧化膜的微观结构,活性元素结合进入氧化膜并在外层膜中(约几十nm)富集,活性元素Ce抗氧化机理不同于Y,Ce使合金氧化膜的空位缺陷显著降低,主要控制了阳离子沿晶格空位向外扩散,而含Y合金由氧化初期主要控制阳离子沿晶格扩散转变为主要控制阳离子沿晶界向外扩散。
Effect of reactive elements Y and Ce on high temperature oxidation ofFe-25Cr-40Ni alloy as well as on composition and microstructure of oxidized layer has beenstudied by ion backscattering and slow positron beam. The reactive element, not more than0.05%, may decrease the oxidation rate at early stage, accelerate the Cr_2O_3 growth, retard theFe and Ni oxides formation and improve the microstructure of oxidized layer. They enter theoxidized layer and concentrate within several tens nm from surface of outer layer. The resistancemechanism to oxidation for Ce seems to be different from Y. Ce may decrease the density of va-cancy defects in oxidized layer so that the diffusion outward of cations through vacancies is re-strained. While Y may affect the restraint of cations diffusion outward through vacancies at ear-ly stage to change into that along grain boundaries.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%