生长气氛和速度在金红石(TiO2)单晶体生长中的作用研究

本文研究了生长气氛和生长速度在焰熔法金红石单晶体生长中的作用,对比了晶体在空气中与在氧气中退火的结果,测定了晶体试样的摇摆曲线和透过率.研究表明:金红石单晶体的生长受炉膛气氛、生长界面温度和生长速度的影响;炉膛气氛决定晶体能否形成,是关键因素;炉膛气氛中的氧分压大于液固界面(即生长界面)处熔体的氧离解压是生长完整晶体的前提条件;晶体在退火过程中消除热应力,但更重要的是通过氧化反应消除氧空位,在氧气氛中退火,可明显缩短退火时间.在所优化的实验条件下制备的晶体,完整性较好,透过率为70～72;,与商用晶体的透过率基本一致.

Study on Effect of Growth Atmosphere and Rate on Preparation of Rutile (TiO2) Single Crystal

The effect of growth atmosphere and rate on the preparation of rutile single crystal in the flame fusion method was mainly studied in this paper. The annealed result in air was compared with it in oxygen. Swing curve and transmissivity of the sample were measured. It was made clear that crystal growth is influenced by chamber atmosphere, temperature at the liquid-solid interface and growth rate, and that the chamber atmosphere is an essential factor on whether crystal could be formed or not. To form a perfect crystal it's a necessary condition that the partial pressure of oxygen at the liquid-solid interface is higher than its decomposed pressure. The role of annealing is to relieve thermal stress formed in crystal growth. However, the more important role of annealing is the oxidization reaction to eliminate oxygen vacancies .The annealing time could be considerably shortened in oxygen. The crystal grown in the optimal experimental condition has good perfection and it's transmissivity is 70-72%, close to commercial crystal.