摘要
高温稀土晶体的快速生长能够在很大程度上降低晶体的生长成本,然而过快的生长速度会造成熔体上方过冷,带来晶体开裂等严重的质量问题.本文从生长界面处的微观化学键合结构出发研究晶体的可控生长过程,理论上证明了结晶热力学和动力学协同控制晶体生长界面处的化学键合过程.计算结果表明界面处化学键合结构在单晶生长中具有决定性作用.本文还从轨道杂化的角度研究了稀土离子的成键特性,可用于研究稀土离子在生长界面处的化学键合结构.针对大尺寸稀土氧化物晶体,结晶生长的化学键合理论可以定量优化晶体的系列生长参数,将各向异性的结晶热力学表达和各向同性的结晶动力学表达控制在不同尺度区间,实现高品质稀土晶体快速生长.
Fast growth of rare earth single crystals with high melting point can effectively reduce the cost of crystal growth. However, too fast growth rate will cause supercooling upon the melt interface, which will result in a series of quality problems such as cracking. In this paper, the crystal growth process is studied from the perspective of chemical bonding at the growing interface. Combining the potential variations of crystal constituents and the coupling of chemical reaction and diffusion at the growing interface, we demonstrate that both crystallization thermodynamics and kinetics coordinately control the chemical bonding process and enhance the dominant role of chemical bonding architectures at the growing interface during crystal growth. In addition, the bonding characteristics of rare earth ions are further studied in the view of the orbital hybridization, which is useful to study the chemical bonding architecture of rare earth ions at the growing interface. For large-size rare earth oxide single crystals, the optimized crystal growth parameters can be designed on the basis of chemical bonding theory of single crystal growth. These growth parameters promote the anisotropic crystal thermodynamic expression and the isotropic crystal kinetic expression that are controlled in different scales, and help to realize the fast growth of large-size rare earth single crystals with high quality.
作者
孙丛婷
薛冬峰
Congting Sun;Dongfeng Xue(State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022.China)
出处
《中国科学：化学》
CAS
CSCD
北大核心
2018年第8期804-814,共11页
SCIENTIA SINICA Chimica
基金
国家重点研发计划"材料基因工程关键技术与支撑平台"重点专项(编号:2016YFB0701004)资助项目
关键词
稀土晶体
结晶生长的化学键合理论
快速生长
轨道杂化
生长界面
rare earth crystals
chemical bonding theory of single crystal growth
fast growth
orbital hybridization
growing interface
作者简介
通讯作者:薛冬峰,E-mail:dongfeng@ciac.ac.cn
