掺碳钛宝石晶体定向开裂的机理研究
- 上海大学电子信息材料系,上海200072 中国科学院上海硅酸盐研究所,上海201800
- 中国科学院上海硅酸盐研究所,上海,201800
- 上海大学电子信息材料系,上海,200072
摘要: 采用下降法生长技术，沿a向[1120]生长的掺碳钛宝石晶体，在切割等加工过程中掺碳钛宝石晶体经常发生定向开裂的现象．本文对掺碳钛宝石晶体的定向开裂特征和机理进行了分析与研究，发现定向裂纹是在基质氧化铝晶格的（1100）面上发源，并且沿着f00011晶向即c轴方向扩展．采用晶体结构可视化软件（Crystalmaker）模拟得出，基质氧化铝晶格原子在（1100）面上的原子排列最为稀疏，并且在（1100）晶面上，垂直[0001]晶向相邻原子间距最大，在应力作用下晶格（1100）[0001]系统的开裂强度最低．采用光学显微镜、扫描电镜（SEM）和电子探针等仪器和手段，发现在开裂的掺碳钛宝石晶体中沉积了不规则的碳包裹物，降温过程中包裹物的热膨胀失配引起巨大的内应力，使得裂纹在晶体最薄弱的系统（1100）[0001]面上发源并扩展，导致晶体的宏观定向开裂．该研究对优质钛宝石晶体的生长具有重要的理论和现实意义．
Mechanism of directional cracking of Ti,C:sapphire crystal
- 上海大学电子信息材料系,上海200072 中国科学院上海硅酸盐研究所,上海201800
- 中国科学院上海硅酸盐研究所,上海,201800
- 上海大学电子信息材料系,上海,200072
Keywords:
- 掺碳钛宝石晶体 /
- 碳包裹物 /
- 定向开裂
Abstract: Directional cracking in Ti,C:sapphire crystals grown along [11 - 20] by Vertical Bridgman method often occurs in the cutting and processing process. In this work, we discuss the characteristic and mechanism of directional cracking of Ti,C:sapphire, and find that directional cracking originates from (-1100) lattice plane and spreads along [0001] orientation. Through the Crystalmaker Simulation software, we find that atomic arrangement on (-1100) lattice plane is the most sparse and adjacent atomic spacing is the largest along vertical [0001] direction, so in the system (-1100) [0001] of lattice has a minimum cracking strength, Irregular carbon inclusions in the cracked Ti,C:sapphire are observed with optical microscopy, scanning electron microscopy (SEM), and X-ray diffractometry. These inclusions cause great internal stress in the cooling process due to thermal expansion mismatch and cracking originating from and spreading in the weak system (1100) [0001] of lattice. As a consequence, macroscopic directional cracking is observed in the Ti,C:sapphire. The study has important theoretical and practical significance for growing high-quality Ti,C:sapphire crystal.
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