中国物理B ›› 2012, Vol. 21 ›› Issue (1): 16105-016105.doi: 10.1088/1674-1056/21/1/016105

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Interaction between impurity nitrogen and tungsten: a first-principles investigation

金硕1, 张颖1, 刘悦林2   

  1. (1)Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191, China; (2)Department of Physics, Yantai University, Yantai 264005, China
  • 收稿日期:2011-05-05 修回日期:2011-07-21 出版日期:2012-01-15 发布日期:2012-01-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 50871009 and 51101135) and the National Magnetic Confinement Fusion Program, China (Grant No. 2009GB106003).

Interaction between impurity nitrogen and tungsten: a first-principles investigation

Liu Yue-Lin(刘悦林)a)†, Jin Shuo(金硕)b), and Zhang Ying(张颖)b)   

  1. a Department of Physics, Yantai University, Yantai 264005, China; b Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
  • Received:2011-05-05 Revised:2011-07-21 Online:2012-01-15 Published:2012-01-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 50871009 and 51101135) and the National Magnetic Confinement Fusion Program, China (Grant No. 2009GB106003).

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摘要： We investigate the stability, diffusion, and impurity concentration of nitrogen in intrinsic tungsten single crystal employing a first-principles method, and find that a single nitrogen atom is energetically favourable for sitting at the octahedral interstitial site. A nitrogen atom prefers to diffuse between the two nearest neighboring octahedral interstitial sites with a diffusion barrier of 0.72 eV. The diffusion coefficient is determined as a function of temperature and expressed as D(N)=1.66×10-7exp (-0.72/kT). The solubility of nitrogen is estimated in intrinsic tungsten in terms of Sieverts' law. The concentration of the nitrogen impurity is found to be 4.82×10-16 Å-3 at a temperature of 600 K and a pressure of 1 Pa. A single nitrogen atom can easily sit in an off-vacancy-centre position close to the octahedral interstitial site. There exists a strong attraction between nitrogen and a vacancy with a large binding energy of 1.40 eV. We believe that these results can provide a good reference for the understanding of the behaviour of nitrogen in intrinsic tungsten.

关键词: tungsten, nitrogen, diffusion, first-principles

Abstract: We investigate the stability, diffusion, and impurity concentration of nitrogen in intrinsic tungsten single crystal employing a first-principles method, and find that a single nitrogen atom is energetically favourable for sitting at the octahedral interstitial site. A nitrogen atom prefers to diffuse between the two nearest neighboring octahedral interstitial sites with a diffusion barrier of 0.72 eV. The diffusion coefficient is determined as a function of temperature and expressed as D(N)=1.66×10-7exp (-0.72/kT). The solubility of nitrogen is estimated in intrinsic tungsten in terms of Sieverts' law. The concentration of the nitrogen impurity is found to be 4.82×10-16 Å-3 at a temperature of 600 K and a pressure of 1 Pa. A single nitrogen atom can easily sit in an off-vacancy-centre position close to the octahedral interstitial site. There exists a strong attraction between nitrogen and a vacancy with a large binding energy of 1.40 eV. We believe that these results can provide a good reference for the understanding of the behaviour of nitrogen in intrinsic tungsten.

Key words: tungsten, nitrogen, diffusion , first-principles

中图分类号:  (Metals and alloys)

  • 61.82.Bg
71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 66.30.J- (Diffusion of impurities ?) 64.75.Bc (Solubility)