Effect of external electric field on diffusivity and flash sintering of 8YSZ: A molecular dynamics study
Effect of external electric field on diffusivity and flash sintering of 8YSZ: A molecular dynamics study
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外电场对 8YSZ 扩散率和闪速烧结的影响：分子动力学研究
DOI：
10.1016/j.actamat.2020.116596
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发表时间：
2021
期刊：
影响因子：
9.4
通讯作者：
Olevsky, Eugene
中科院分区：
文献类型：
--
作者：
Xu, Wenwu;Maksymenko, Andrey;Hasan, Shahrier;Meléndez, Juan J.;Olevsky, Eugene
采用分子动力学（MD）模拟方法研究了高温下外加电场对8 YSZ的原子结构和离子扩散的影响。作为例子，研究了双晶∑ 5（310）/[001]晶界模型的原子组态的充分大系统。分子动力学结果表明，电场促进了Frenkel对缺陷的形成。值得注意的是，一些Zr离子在电场> 1000 - 1000 V/cm时扩散出GB区，导致GB处阳离子空位的“雪崩”和GB空间电荷的减少。因此，阳离子和阴离子的扩散系数增强在8 YSZ系统与电场的存在下。电场诱导的结构变化和离子扩散系数的原子水平的理解提供了一个深入的见解，以解开闪速烧结离子陶瓷的机制，特别是在闪速烧结过程中的耦合热场效应。
The atomistic structural modification and ionic diffusivity in 8YSZ at elevated temperature with the presence of an external electric field (E-field) were investigated by molecular dynamics (MD) simulations. As an example, a sufficiently large system of atomic configuration for a bi-crystal∑ 5 (310)/[001] grain boundary (GB) model was studied. MD results show that the E-field promotes the formation of Frenkel pair defects. Notably, some Zr ions diffuse out of GB regions at E-field>∼ 500-1000V/cm, resulting in an “avalanche” of cation vacancies at GBs and reduction of GB space charge. Consequently, the diffusivities of cations and anions are enhanced in the 8YSZ system with the presence of E-field. The atomistic level understanding of E-field induced structural modifications and ionic diffusivities provide an in-depth insight to unravel the flash sintering mechanisms of ionic ceramics, especially the coupled thermal-field effect during the flash sintering process.