人工合成橄榄石单晶方法综述

An overview of olivine single crystal growth methods

橄榄石是上地幔的主要造岩矿物,研究橄榄石在高温高压下的物理化学性质是了解地幔对流、板块运动等地球动力学过程的基础.一些研究橄榄石物理化学性质的实验需要用到橄榄石单晶,例如在实验室中进行的变形实验,无论是双轴压缩、三轴压缩、简单剪切,还是扭转变形实验等等.近年来,水对橄榄石蠕变性质的影响被广泛关注,橄榄石的含水测量也需要用到大尺寸的橄榄石单晶.除了实验室需要大晶体,合成晶体也是新材料领域的研究热点和发展前沿,目前国内外人工合成单晶的方法包括从固相、液相、气相以及从熔体中合成晶体.在人工合成橄榄石单晶方面,目前主要使用的方法包括提拉法、浮区法和烧结法.本文综述了从固相、液相、气相以及从熔体中合成晶体的方法,详细介绍了人工合成橄榄石单晶所采用的提拉法、浮区法和烧结法等三种方法的原理与合成过程,讨论了不同方法的优缺点,其中烧结法合成单晶需要的时间短,但是对温度以及实验的氧化还原环境要求较高;浮区法生长大的单晶耗时短、可以得到大尺寸的单晶,但对工艺技术要求高;提拉法可以通过籽晶的取向来制备不同晶体取向的单晶,过程容易控制,但是由于使用坩埚而容易污染,不适用于对于固态下有相变的晶体.通过以上研究,本文提出了以后生长大尺寸橄榄石单晶的可能途径,希望对橄榄石单晶的制备方面工作提供参考.

Olivine is the dominant mineral in the earth mantle. Understanding the chemical and physical properties of olivine under high temperature and high pressure is the foundation of studying the mantle dynamics processes such as mantle convection, plate tectonics etal. Biaxial, triaxial compression, simple shear and torsion experiment need olivine single crystals. In recent years, the effect of water on olivine creep property becomes a hot spot, and water solubility experiment needs large olivine single crystals too. Synthetic crystal is also a hot research topic in the field of new materials. The method of synthesizing single crystals includes synthesis of crystals from solid phase, liquid phase, gas phase and melt. The main methods to synthesize olivine single crystal include pulling method, floating zone method and sintering method. This paper reviewed all the methods of synthesizing single crystal, including getting single crystal from the solid phase, liquid phase and gas phase, as well as from melt material. We introduced the methods to synthesize the olivine single crystal in detail. The methods include Czochralski method, floating zone method and sintering method. We also summarized the advantage and disadvantage of each method. Sintering method to synthesize single crystal saves time, but the temperature and the gas environment are hard to control. Floating zone method needs less time and is possible to get large single crystals, but it＇s also hard to control. Pulling method can use seed crystal of different orientation to prepare different orientated single crystal. It＇s easy to control, but also easy to get polluted due to the use of crucible. This method does not apply to the crystal which will change phase under solid state. From the above, we put forward possible ways of larger olivine crystal growth. After all, we hope this work will provide the reference to people who want to make large olivine single crystal.