Spherical sapphire single-crystal synthesis by aerodynamic levitation with high growth rate
Spherical sapphire single-crystal synthesis by aerodynamic levitation with high growth rate
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DOI：
10.1063/1.1763254
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发表时间：
2004-07-01
影响因子：
1.6
通讯作者：
Yoda, S
中科院分区：
文献类型：
--
作者：
Arai, Y;Aoyama, T;Yoda, S
本文介绍了一种应用单向凝固方法通过气动悬浮器形成球形Al2O3单晶的技术。悬浮方法本质上产生球形材料。此外，聚焦激光束加热和流向悬浮器中捕获的样品的气体都会在熔融样品中产生陡峭的温度梯度，使样品能够以高生长速率生长。球形蓝宝石单晶生产由两道工序组成。第一步是从样品底部的多晶部分单向固化熔融样品。该样品几乎是单晶，多晶部分仅保留在底部。然后在第二步之前旋转晶体。在第二步中，旋转的晶体从多晶部分重熔并从晶种固化，从而形成完整的单晶生产。直径为2 mm的Al2O3球状晶体的X射线劳厄和正交尼科尔实验结果表明，已经产生了无孪晶块状单晶。在这两个步骤中，在 60 mm/h 的生长速率下，晶体中没有宏观空隙或裂纹。另外，晶体的六边形形状似乎是天然刚玉的习性平面。这表明生长方向是沿着蓝宝石的 c 轴。 (C) 2004 年美国物理研究所。
This article describes a technique for forming spherical Al2O3 single crystals by an aerodynamic levitator by applying the unidirectional solidification method. A levitation method intrinsically produces a spherical material. In addition, both the focused laser beam heating and the gas flows to the sample trapped in the levitator generate a steep temperature gradient in the molten sample, enabling the sample to grow with high growth rate. Spherical sapphire single-crystal production consists of two processes. First step is to solidify the molten sample unidirectionally from polycrystalline parts at the bottom of the sample. This sample was almost a single crystal with polycrystalline parts remaining just around the bottom. The crystal is then revolved before the second step. In the second step the revolved crystal was remelted from the polycrystalline part and solidified from the seed, resulting in complete single-crystal production. The x-ray Laue and crossed nicol experiment results for the Al2O3 spherical crystal with 2 mm diameter demonstrated that twin-free bulk single crystal had been produced. There were no macroscopic voids or cracks in the crystal at 60 mm/h growth rates in both steps. In addition, a hexagonal shape of the crystal seems to be the habit-plane of a natural corundum. This indicates the growth direction was along the c-axis of a sapphire. (C) 2004 American Institute of Physics.