Characterization of Anisotropic Electric Field Effects on Grain Boundary Structures in Oxide Ceramics
Characterization of Anisotropic Electric Field Effects on Grain Boundary Structures in Oxide Ceramics
复制标题
氧化物陶瓷晶界结构各向异性电场效应的表征
DOI：
10.1093/micmic/ozad067.841
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发表时间：
2023
影响因子：
2.8
通讯作者：
van Benthem, Klaus
中科院分区：
文献类型：
--
作者：
Hahn, William;Qu, Boyi;Eiteneer, Daria;Wood, Joseph;van Benthem, Klaus
在烧结过程中施加电场可以增强非导电陶瓷的致密化[1]，并可能改变晶粒生长行为[2，3]。使用原位TEM，Majidi和van Bentem [4]直接成像了在没有可观察到电流的电场存在下ZrO 2纳米颗粒团聚体的增强致密化。货车Bentem [4]。虽然致密化和晶粒生长是由晶界控制的，但是外部施加的电场如何改变晶界结构和局部键合构型的机制仍然没有被探索。使用专门的双晶体实验，我们最近已经证明了穿过晶界平面的电场可以改变界面宽度，即，SrTiO_3中（100）扭曲晶界的原子和电子结构[5]。EELS实验揭示了晶界核心内的氧空位配置的修改。电场强度的增加导致了晶界核心结构附近的阴离子无序化（见图1）。在单独的热退火实验期间，电场被施加沿着相同晶界的平面。STEM表征已经证明了在正极附近约0.8nm的晶界膨胀，而在负极附近界面宽度减小至约0.4nm。对于一个足够高的场强界面分解观察。EELS和XPS实验揭示了靠近负电极的氧亚晶格畸变，并且与本体相比，Ti 3+和Ti 2+的浓度增强。通过外加电场导致氧沿着晶界平面迁移来解释结果[6]。
The application of electric fields during sintering can enhance densification in non-conducting ceramics [1] and may alter grain growth behavior [2, 3]. Using in-situ TEM Majidi and van Benthem [4] have directly imaged enhanced densification of ZrO2 nanoparticle agglomerates in the presence of electric fields with no observable current flow. While densification and grain growth are governed by grain boundaries, the mechanisms how externally applied electric fields alter grain boundary structures and local bonding configurations remain mostly unexplored.Using dedicated bicrystal experiments we have recently demonstrated that electric fields directed across grain boundary planes can alter the interfacial width, ie, the atomic and electronic structures of (100) twist grain boundaries in SrTiO3 [5]. EELS experiments have revealed modifications of the oxygen vacancy configurations within the grain boundary cores. Increasing field strengths have caused anion disordering in the vicinity of the grain boundary core structures (see Fig. 1). During separate thermal annealing experiments electric fields were applied along the planes of the same grain boundary. STEM characterization has demonstrated grain boundary expansions around 0.8 nm near the positive electrode while the interface width decreased to around 0.4 nm close to the negative electrode. For a sufficiently high field strength interface decomposition was observed. EELS and XPS experiments revealed oxygen sublattice distortions close to the negative electrode and enhanced concentrations of Ti3+ and Ti2+ compared to the bulk. The results are interpreted by oxygen migration along the grain boundary plane due to the applied electric field [6].