Ca对氧化铝晶界处氧空位扩散的活化机理  

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

作　　者：马帅 李拥华[1] 高裕博 MA Shuai;LI Yonghua;GAO Yubo(College of Sciences,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学理学院,上海200444

出　　处：《上海大学学报（自然科学版）》2020年第4期562-569,共8页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金青年科学基金资助项目(11004128)。

摘　　要：通过第一性原理方法计算了α-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α-Al2O3晶界有活化的作用,促进晶界处的VO的形成和扩散。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 α-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 α-Al2O3.

关 键 词：氧化铝 晶界 掺杂 第一性原理 

分 类 号：O469[理学—凝聚态物理]