采用提拉法制备了LuxY1-xAlO3:Ce晶体样品, 通过XRD物相分析和成分分析, 并结合Lu2O 3-Al2O3二元体系相图以及LuxY1-x AlO3:Ce结构稳定性方面的分析与讨论, 结果表明: 随着熔体中Lu元素含量的增加, 熔体分层加剧, 析晶LuxY1-xAlO3:Ce相的熔体组成区间将向富Lu一侧偏移, 这使得晶体上部易伴生(Lu,Y)3Al5O12:Ce相; 而随着Lu元素含量的提高, LuxY1-xAlO3:Ce晶体的热稳定性降低, 氧空位的存在则使晶体的热稳定性进一步降低, 在接种过程中籽晶表面易发生相分解反应生成(Lu,Y)3 Al5O12:Ce和(Lu,Y) 4 Al2O9:Ce, 籽晶表面相分解产物(Lu,Y)3Al5O12:Ce提供了诱导析晶(Lu,Y)3Al5O12 :Ce相所需的晶核, 这使得晶体的外
表面处易伴生(Lu,Y)3Al5O12:Ce相. 调整配料组成使 n(Lu,Y)2O3 ): n (Al2O3)=1.17～1.00, 加大熔体内部和固液界面处的温度梯度以改善熔体对流、抑制熔体分层以及籽晶表面处的相分解等有助于高Lu元素含量LuxY1-xAlO3 :Ce晶体的获得.
丁栋舟
,
陆晟
,
潘尚可
,
张卫东
,
王广东
,
任国浩
. LuxY1-xAl 3:Ce晶体中伴生(Lu,Y3 Al5O12:Ce相成因研究[J]. 无机材料学报, 2008
, 23(3)
: 434
-438
.
DOI: 10.3724/SP.J.1077.2008.00434
LuxY1-xAlO3:Ce single crystal samples were prepared by the Czochralski method. Based on X-ray diffraction (XRD) and composition analyses, and analysis of phase diagram of Lu2O 3-Al2O3 and the structural stability of LuxY1-xAlO3:Ce, it is supposed that as the content of Lu increase, the melt delamination is exacerbated, and the crystallization interval of Lux 1-xAlO3:Ce in the phase diagram may shift towards the interval rich in Lu, resulting in the accompaniment of (Lu,Y)3Al5O12:Ce on the top of LuxY1-xAlO3 :Ce single crystals. With the increase of the content of Lu, the thermal stability of LuxY1-xAlO3:Ce single crystals decreases, the oxygen vacancy in those crystals furthers the decrease, so the seed surface tends to decompose into (Lu,Y3 Al5O12:Ce and (Lu,Y)4Al2O9:Ce while seeding, and the former decomposition product provides the crystal nucleus to induce crystallization of (Lu,Y3Al 5O12:Ce, resulting in the accompaniment of (Lu,Y)3Al5O12:Ce on the coat of LuxY1-xAlO3:Ce single crystals. An adjustment of the melt composition to make the mol ratio n((Lu,Y)2O3):n(Al2O3) equal to 1.17--1.00, and a greater temperature gradient inside the melt and at the solid liquid interface to improve melt convection, restrain melt delamination and the decomposition on the seed surface may contribute to the acquisition of Lux Y1-xAlO3:Ce with high Lu content.
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