平衡态法对受主掺杂在钛酸钡晶界处偏析机理的研究

As described in the latest grain boundary research method-equilibrium method, by means of advanced coating technologies, complex grain boundary could be simulated as thick equilibrium films for directly characterization and analysis. Besides, accepter dopant can induce grain boundary segregation in barium titanate, which has strong effect on the physical properties of matrix materials. However, results on the grain boundary segregation researches need more direct experiment evidence and universality. In our research project, equilibrium method will be used to study the actual grain boundary in accepter doped barium titanate. The complex structure of grain boundary can be simulated by advanced coating technology as thick equilibrium films. Omnifaceted physical properties will be characterized to get reliable experiment data. Based on analysis on the data, essential grain boundary segregation mechanism will be obtained. This may not only update grain boundary theories, but also provide a new approach to get novel result in the further research in this area. This research project can be outlined as follow: At first, The features and applications of equilibrium method will be studied. The thick equilibrium films simulated from actual grain boundary will be characterized and analyzed to ensure reliability of this simulated grain boundary. This can draw out the applicable conditions and influence factors of this method. Based on the above sections, the actual grain boundary in accepter doped barium titanate can simulated、characterized and analyzed in equilibrium method to obtain reliable grain boundary segregation mechanism. Furthermore, we will also investigate the wider applications of equilibrium method in grain boundary research area.

平衡态法是将晶界的复杂结构用多种镀膜技术模拟出来，对晶界做直接准确的表征及分析的一种新型晶界研究方法。晶界偏析是受主掺杂改善钛酸钡陶瓷性能的主要原因，但该研究尚缺乏具有可靠实验依据的普适性偏析机理。本课题运用平衡态法模拟受主掺杂钛酸钡晶界，通过性能表征及分析计算，获得准确的实验依据，从而得到具有普适性的可靠晶界偏析机理，发展目前的晶界结构理论，为多晶材料的晶界结构研究、晶界性能调控等其他晶界研究领域提供参考。课题深入剖析平衡态法的特点，从实验的角度分析平衡态所得模拟晶界的等效性，对该方法在现有晶界研究中的特点及具体适用条件进行总结和提炼，确保平衡态法的适用性；在此基础上，运用该方法对受主掺杂钛酸钡晶界进行模拟、表征和计算分析，利用该方法的直接可靠性，得到准确有效的实验数据，最终得到可靠的晶界偏析机理；最后，对该方法在晶界结构研究中的进一步应用进行探索。

本项目平衡态法是将晶界的复杂结构用多种镀膜技术模拟出来，对晶界做直接准确的表征及分析的一种新型晶界研究方法。晶界偏析是受主掺杂改善钛酸钡陶瓷性能的主要原因，但该研究尚缺乏具有可靠实验依据的普适性偏析机理。本课题旨在运用平衡态法模拟受主掺杂钛酸钡晶界，得到具有普适性的可靠晶界偏析机理，发展目前的晶界结构理论，为多晶材料的晶界结构研究、晶界性能调控等其他晶界研究领域提供参考。.本项目主要研究内容及结果有三部分：①对平衡态进行试验论证，对模拟钛酸钡晶界方法中的多个条件因素作用效果进行研究，确定了一套可靠的模拟受主掺杂钛酸钡晶界的方法。②研究了受主掺杂在钛酸钡晶界处的偏析机理，以Y作为主要研究掺杂离子，首先通过研究确定了其受主掺杂和施主掺杂的决定因素，其次通过静电纺织法和特定的固相法分别制备了受主掺杂钛酸钡纳米线和施主掺杂巨介电钛酸钡陶瓷，得到了模拟的平衡态晶界，对样品进行性能表征，通过论证分析，确定了掺杂离子对晶界作用的具体效果，并提出了确切的理论模型，得到有意义的结果，并通过反复试验加以验证。③在此基础上，有意识地用平衡态法对其他钙钛矿晶格材料和实际器件进行研究，将晶界作用机理进行推广，既为下一步研究工作打下基础，又将已取得的结果进行反馈和完善。