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JOURNAL OF SYNTHETIC CRYSTALS ›› 2024, Vol. 53 ›› Issue (6): 959-966.

• Research Articles • Previous Articles     Next Articles

Study on the Growth of Type-Ib Diamond Single Crystal and the Temperature Field Distribution in the Synthesis Cavities

XIAO Hongyu1, LI Yong1, TIAN Changhai1, ZHANG Weixi1, WANG Qiang1, XIAO Zhengguo1, WANG Ying1, JIN Hui1, BAO Zhigang2, ZHOU Zhenxiang3   

  1. 1. Department of Physics and Electrical Engineering, Tongren University, Tongren 554300, China;
    2. Department of Mathematics and Physics, Luoyang Institute of Science and Technology, Luoyang 471023, China;
    3. Beijing Sinoma Snythetic Crystals Co., Ltd., Beijing 100018, China
  • Received:2024-01-16 Online:2024-06-15 Published:2024-06-20

Abstract: In this paper, type-Ib diamond single crystals, using two different sizes of synthesis cavities of 15 mm and 30 mm, were synthesized under 5.7 GPa, 1 560~1 600 K, and the temperature field distributions of the two sizes of synthesis cavities were studied using finite element method (FEM). Firstly, the temperature field distributions of two different sizes of synthesis cavities were simulated using finite element method. The average radial temperature gradient and average axial temperature gradient of the 15 mm synthesis cavity are 0.573 and 5.700 K/mm, respectively. The average radial temperature gradient and average axial temperature gradient of the 30 mm cavity are 0.093 and 2.280 K/mm, respectively. The simulation results reveal that the uniformity of the temperature field in the 30 mm synthesis cavity is significantly better than that in the 15 mm synthesis cavity. Secondly, the reproducible growth of high-quality type-Ib diamond large single crystals was achieved using both synthesis cavities mentioned above. The 15 mm synthetic cavity is difficult to achieve the growth of high-quality type-Ib diamond single crystals weighing more than 1.2 ct (1 ct=0.2 g), while the 30 mm synthetic cavity is more suitable for the growth of large-size high-quality type-Ib diamond single crystals. Furthermore, the scanning electron microscopy (SEM) test results show that the surface flatness of high-quality type-Ib diamond single crystals grown using two different sizes of synthesis cavities in this study is good, and the expansion of the synthesis cavity has no significant effect on the crystal quality of Ib diamond single crystal surface. Finally, Raman spectrum test results show that the crystal quality of polycrystalline diamond deteriorates, and other diamond single crystal samples synthesized by two kinds of synthesis cavity in this study have better crystal quality. This research has certain academic reference value for the design of large size synthesis cavity of gem grade diamond single crystal, the growth of large size diamond single crystal, and the perfection of polycrystalline diamond single crystal synthesis technology.

Key words: type-Ib diamond, high pressure and high temperature, temperature gradient method, catalyst, temperature field, polycrystal

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