...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical review >Effect of surface hydrogen on the anomalous surface segregation behavior of Cr in Fe-rich Fe-Cr alloys
【24h】

Effect of surface hydrogen on the anomalous surface segregation behavior of Cr in Fe-rich Fe-Cr alloys

机译：表面氢对富铁Fe-Cr合金中Cr异常表面偏析行为的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The segregation behavior of Cr in dilute Fe-Cr alloys is known to be anomalous since the main barrier for surface segregation of Cr in these alloys arises not from the topmost surface layer but from the subsurface layer where the solution energy of Cr is much more endothermic as compared to the topmost surface layer. The Fe-Cr alloys are candidate structural materials for the new generation of nuclear reactors. The surfaces of these alloys will be exposed to hydrogen or its isotopes in these reactors, and although hydrogen is soluble neither in Fe nor in Fe-Cr alloys, it is known that the adsorption energy of hydrogen on the surface of iron is not only exothermic but relatively large. This clearly raises the question of the effect of the hydrogen adsorbed on the surface of iron on the segregation behavior of chromium towards the surface of iron. In this paper we show, on the basis of our ab initio density functional theory calculations, that the presence of hydrogen on the surface of iron leads to a considerably reduced barrier for Cr segregation to both the topmost surface layer and the subsurface layer, but the subsurface layer still controls the barrier for surface segregation. This reduction in the barrier for surface segregation is due to the nature of the Cr-H couple that acts in a complex and synergistic manner. The presence of Cr enhances the exothermic nature of hydrogen adsorption that in turn leads to a reduced barrier for surface segregation. These results should be included in the multiscale modeling of Fe-Cr alloys.
机译：已知Cr在稀Fe-Cr合金中的偏析行为是反常的，因为这些合金中Cr表面偏析的主要障碍不是由最上层的表层产生，而是由表面下层产生的，Cr的固溶能更多地吸热与最顶层的表面层相比。 Fe-Cr合金是新一代核反应堆的候选结构材料。这些合金的表面将在这些反应器中暴露于氢或其同位素，尽管氢既不溶于铁也不溶于铁铬合金，但众所周知，氢在铁表面的吸附能不仅是放热的但比较大。这显然提出了一个问题，即吸附在铁表面的氢对铬向铁表面的偏析行为的影响。在本文中，根据从头算密度函数理论的计算，我们表明，铁表面上氢的存在会导致Cr隔离到最表面层和次表面层的势垒大大降低，但是地下层仍控制着表面隔离的屏障。表面偏析阻挡层的这种减少是由于以复杂且协同的方式起作用的Cr-H对的性质所致。 Cr的存在增强了氢吸附的放热性质，进而导致表面偏析的屏障减少。这些结果应包括在Fe-Cr合金的多尺度模拟中。

著录项

  • 来源
    《Physical review》 |2012年第18期|184201.1-184201.7|共7页
  • 作者

    Michele Gupta; Raju P. Gupta; Maximilien Levesque;

  • 作者单位

    Laboratoire de Thermodynamique et Physico-Chimie d'Hydrures et Oxydes, Universite de Paris-Sud, 91405 Orsay, France;

    Laboratoire de Thermodynamique et Physico-Chimie d'Hydrures et Oxydes, Universite de Paris-Sud, 91405 Orsay, France;

    Ecole Normale Superieure, Depctrtement de Chimie, UMR 8640 CNRS-ENS-UPMC, 24 Rue Lhomond, 75005 Paris, France and CNRS, UPMC Universite Paris 06, ESPCI, UMR 7195 PECSA, 75005 Paris, France;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    metals and alloys; fe and its alloys; ab initio calculations of adsorbate structure and reactions;

    机译：金属和合金;Fe及其合金;从头计算吸附物的结构和反应;

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号