上海大学学报(自然科学版) ›› 2020, Vol. 26 ›› Issue (4): 562-569.doi: 10.12066/j.issn.1007-2861.2220

• 研究论文 • 上一篇    下一篇

Ca 对氧化铝晶界处氧空位扩散的活化机理

马帅, 李拥华(), 高裕博   

  1. 上海大学 理学院, 上海 200444
  • 收稿日期:2017-03-03 出版日期:2020-08-30 发布日期:2020-09-03
  • 通讯作者: 李拥华 E-mail:lyhua@shu.edu.cn
  • 基金资助:
    国家自然科学基金青年科学基金资助项目(11004128)

Activation mechanism of the effect of Ca on oxygen vacancy diffusion in grain boundary of alpha-Al2O3

MA Shuai, LI Yonghua(), GAO Yubo   

  1. College of Sciences, Shanghai University, Shanghai 200444, China
  • Received:2017-03-03 Online:2020-08-30 Published:2020-09-03
  • Contact: LI Yonghua E-mail:lyhua@shu.edu.cn

摘要:

通过第一性原理方法计算了 alpha-Al2O3的∑3(1010)晶界处 Ca 偏析对时氧空位(oxygen vacancy, VO)形成能和扩散势垒的影响。Ca 偏析到晶界处的稳定位置后,Ca 附近 VO 的形成能为 3.05~4.04 eV,比没有掺杂的晶界处 VO 的形成能降低了 2.5 eV 以上;Ca 附近 VO 扩散的活化能为 2.30 eV, 与没有掺杂的晶界相比,降低达 1.8 eV. 随着晶界处 Ca 浓度的升高,晶界附近的晶格发生明显膨胀,电荷平衡进一步被打破,VO 的形成能降低至 -1.43 eV,扩散的活化能进一步降低至 1.27 eV。 Ca 掺杂对 alpha-Al2O3 晶界有活化的作用,促进晶界处的 VO 的形成和扩散。

关键词: 氧化铝, 晶界, 掺杂, 第一性原理

Abstract:

The formation energy and diffusion barrier of oxygen vacancies (VO) were calculated using the first-principles density functional theory method, for the case of Ca segregated in the ∑3(1010) grain boundary of $\alpha alpha-Al2O3. The formation energy of Vo fell in the 3.05~4.04 eV range in the Ca doped grain boundary. This was roughly 2.5 eV lower than the undoped grain boundary. The activation energy of VO in the Ca-doped grain boundary changed to 2.30 eV, 1.8 eV less than the undoped grain boundary's maximum. Moreover, with the increase in the concentration of Ca, the crystal lattice near the grain boundary underwent significant expansion, further breaking the balance of charge. Therefore, the formation energy of VO was further reduced to -1.43 eV, and the diffusion activation energy was reduced to 1.27 eV. Thus, Ca doping proved advantageous in the formation and diffusion of VO in the grain boundary of $\alpha alpha-Al2O3.

Key words: alumina oxide, grain boundary, doping, first-principles

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