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低压下用CO+H2气体制备人造金刚石的相图计算

张卫; 万永中; 王季陶   

  1. 复旦大学电子工程系; 上海200433
  • 收稿日期:1996-04-22 修回日期:1996-06-03 出版日期:1997-06-20 网络出版日期:1997-06-20

Calculation of Diamond Phase Diagrams in the CO/H2 System under Low Pressure

ZHANG Wei; WAN Yongzhong; WANG Jitao   

  1. Department of Electronic Engineering; Fudan University Shanghai 200433 China
  • Received:1996-04-22 Revised:1996-06-03 Published:1997-06-20 Online:1997-06-20

摘要: 用非平衡热力学耦合模型计算了低压下由CO+H2气体制备人造金刚石的相图.这些相图与经典的平衡热力学理论计算的相图不同,都有一个金刚石生长区.金刚石生长区的存在是实现用CO+H2气体制备人造金刚石的热力学基础.本文认为相图中的金刚石生长区是体系中超平衡氢原子和超平衡氧原子对金刚石相和石墨相不同作用的结果.不同压力下相图中金刚石生长区的范围稍有不同,压力降低时,金刚石生长区将向低CO浓度的方向移动.本文还将计算的结果与报道的实验结果进行了对比分析,两者基本相符.

关键词: 金刚石, 相图, 化学气相淀积

Abstract: The phase diagrams of diamond synthesis in CO+H2 mixture gases were obtAlNed accordingto non-equilibrium thermodynamic coupling model. Thesc phase diagrams have diamond stabilityregions, which arc different from tile phase diagrams predicted by classical equilibrium thermodynamic theory. The existence of diamond stability regions is attributed to the distinctive effectsof super-equilibrium atomic hydrogen and atomic oxygen on diamond and graphite. With thepressure decreasing, the diamond stability region moves toward low CO concentration end. The diamond stability regions calculated in the present work are in agreement with the experimental results reported in literatures.

Key words: diamond, phase diagram, chemical vapor deposition