Stishovite single-crystal growth and application to silicon self-diffusion measurements
Stishovite single-crystal growth and application to silicon self-diffusion measurements
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DOI：
10.2138/am.2010.3255
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发表时间：
2010
影响因子：
3.1
通讯作者：
A. Shatskiy;D. Yamazaki;Y. Borzdov;Takuya Matsuzaki;K. Litasov;T. Cooray;A. Ferot;E. Ito;T. Ka
中科院分区：
文献类型：
--
作者：
A. Shatskiy;D. Yamazaki;Y. Borzdov;Takuya Matsuzaki;K. Litasov;T. Cooray;A. Ferot;E. Ito;T. Ka
摘要 在 11 GPa 的压力下，从二氧化硅水溶液中成功合成了大的石英石单晶。研究了缓慢冷却和热梯度方法的潜力。热梯度法使用石英石作为二氧化硅源，在 1350 °C 和 50 °C/mm 的热梯度下生长出尺寸为 0.8 × 0.8 × 1.3 mm 的晶体。使用石英作为来源导致溶液内部出现大量的石英晶体，导致大晶体生长的空间减少。这可以通过亚稳态石英和石英在水中的溶解度存在显着差异来解释，在 1000 °C 和 11 GPa 下，估计分别为 85.3 wt% 和 5.6 wt% SiO2。在 SiO2 + 14.7 wt% H2O 体系中，以 2 °C/min 的冷却速率将温度从 1600 °C 降至 1000 °C，通过缓慢冷却方法生长出最大 0.8 × 1.3 × 1.5 mm 的晶体。获得的单晶尺寸足够大，可以进行硅自扩散实验，该实验是在14 GPa的压力和1400至1800°C的温度下进行的。沿[110]和[001]方向的晶格扩散系数可分别表示为D[110] (m2/s) = 4.10 × 10-12 exp [-322 (kJ/mol)/RT]和D[001] (m2/s) = 5.62 × 10-12 exp [-334 (kJ/mol)/RT]，其中R是气体常数，T是气体常数绝对温度。
Abstract Large single crystals of stishovite were successfully synthesized at 11 GPa from a silica solution in water. The potential of both slow cooling and thermal gradient methods were examined. The thermal gradient method provided crystals of 0.8 × 0.8 × 1.3 mm in size grown at 1350 °C and a thermal gradient of 50 °C/mm using stishovite as a silica source. The use of quartz as a source resulted in the appearance of numerous stishovite crystals in the solution interior resulting in diminished space for the growth of large crystals. This can be explained by a significant difference in the solubility of metastable quartz and stishovite in water, estimated to be 85.3 and 5.6 wt% SiO2 at 1000 °C and 11 GPa, respectively. Crystals up to 0.8 × 1.3 × 1.5 mm were grown by the slow cooling method in the system SiO2 + 14.7 wt% H2O as temperature was decreased from 1600 to 1000 °C with a cooling rate of 2 °C/min. The size of single crystals obtained was large enough to carry out silicon self-diffusion experiments, which were performed at a pressure of 14 GPa and temperatures from 1400 to 1800 °C. The lattice diffusion coefficients along the [110] and [001] directions can be expressed as D[110] (m2/s) = 4.10 × 10-12 exp [-322 (kJ/mol)/RT] and D[001] (m2/s) = 5.62 × 10-12 exp [-334 (kJ/mol)/RT], respectively, where R is the gas constant and T is the absolute temperature.