Atomic and Electronic Structure of Ceramic Bicrystals and High Temperature Strength

陶瓷双晶的原子电子结构及高温强度

基本信息

批准号：
09450256
负责人：
IKUHARA Yuichi
金额：
$ 8.64万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450256/
关键词：
Bicrystal Almina Zirconia High resolution electron microscopy Electron energy loss spectroscopy Molecular orbital method Image simulation CSL boundary

项目摘要

Mechanical properties of ceramics are closely related to the atomic structure and chemical bonding state in the grain boundaries. Therefore, the relationships between properties and grain boundary structure are needed to be clarified in order to obtain a guideline to design high strength and high reliable ceramics. In this study, 1 : Fabrication of ceramics bicrystals, 2 : Evaluation of grain boundary atomic and electronic structure, 3 : Grain boundary characteristics and grain boundary sliding, and 4 : Effect of grain boundary segregation were systematically investigated and the following results were obtained.1 : Fabrication of ceramicsZirconia bicrystals with [110] tilt boundaries and alumina bicrystals with [1120] tilt boundaries were fabricated by joining two single crystals at high temperatures. Their grain boundary energy was measured by observing the profiles of thermal grooving by an atomic force microscope. It was found that the grain boundary energy depends on the grain boun … More dary characteristics and shows the energy cusp at the tilt angles corresponding to CSL orientation.2 : Evaluation of grain boundary atomic and electronic structureGrain boundary atomic structures in the bicrystals were determined by combing HREM image and the image simulation technique. The obtained structures were compared with the atomic structures deduced by molecular orbital method. The experimental results agreed well with the theoretically obtained structures.3 : Grain boundary characteristics and grain boundary slidingIt was found that the grain boundary sliding were influenced by the grain boundary characteristics. However, grain boundary sliding is mainly controlled by the grain boundary atomistic configuration, rather than grain boundary energy.4 : Effect of grain boundary segregationGrain boundary segregation was investigated by EDS and EELS by using nano probe in a field emission electron microscope. It was found that the chemical composition and chemical bonding state in the segregation strongly depended on the grain boundary characteristics. Grain boundary chemical bonding state was evaluated by comparing the EELS spectra and partial density of state calculated by the molecular orbital method. Less

陶瓷的机械性能与晶界的原子结构和化学键状态密切相关，因此需要阐明性能与晶界结构之间的关系，以获得设计高强度和高可靠性陶瓷的指导。在这项研究中，1：陶瓷双晶的制造，2：晶界原子和电子结构的评估，3：晶界特征和晶界滑动，4：晶界偏析的影响进行了系统的研究和研究获得了以下结果。1：陶瓷的制备通过在高温下连接两个单晶来制备具有[110]倾斜晶界的氧化锆双晶和具有[1120]倾斜晶界的氧化铝双晶，通过观察热分布来测量它们的晶界能量。通过原子力显微镜进行开槽发现，晶界能量取决于晶粒弹跳特性，并在倾斜角度处显示出能量尖点。 2：晶界原子和电子结构的评价结合HREM图像和图像模拟技术确定了双晶中的晶界原子结构，并将所得结构与分子轨道法推导的原子结构进行了比较。结果与理论得到的结构非常吻合。3：晶界特征和晶界滑动发现晶界滑动受晶界特征的影响，但晶界滑动主要受晶界原子控制。结构，而不是晶界能量。4：晶界偏析的影响通过使用场发射电子显微镜中的纳米探针，通过EDS和EELS对晶界偏析进行了深入研究，发现偏析依赖于化学成分和化学键合状态。通过比较 EELS 光谱和分子轨道法计算的部分状态密度来评估晶界化学键状态。