Experimental study on the stability of graphitic C3N4 under high pressure and high temperature
Experimental study on the stability of graphitic C3N4 under high pressure and high temperature
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DOI：
10.1016/j.diamond.2011.03.034
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发表时间：
2011-05-01
影响因子：
4.1
通讯作者：
Irifune, Tetsuo
中科院分区：
文献类型：
--
作者：
Fang, Leiming;Ohfuji, Hiroaki;Irifune, Tetsuo
通过多砧台实验和对淬火产物的物相表征，研究了石墨化C3N4(g-C3N4)在10-25 Gpa和2000℃的压力和温度范围内的稳定性和分解。G-C3N4被发现在相对温和的温度下保持稳定，但在600-700摄氏度以上和15 GPa时分解为石墨和氮气，而在800-900摄氏度和22-25 GPa时直接分解为钻石(加氮气)。G-C3N4的估计分解曲线在22 GPa时有一个正斜率(类似于0.05 GPA/K)，但在这个压力以上变得反转(负)。分解形成的金刚石具有自生晶体的特征，这些晶体并不相互烧结，而是松散地聚集在一起，表明结晶是在液体(氮)介质中进行的。从石墨化C-N骨架中释放出的氮也可能在降低金刚石形成所需的激活能和提高颗粒生长速度方面发挥重要作用。在所研究的P-T范围内没有发现g-C3N4的相变。(C)2011爱思唯尔B.V.保留所有权利。
The stability and decomposition of graphitic C3N4 (g-C3N4) were studied in the pressure and temperature range of 10-25 GPa and up to 2000 degrees C by multi-anvil experiments and phase characterization of the quenched products. g-C3N4 was found to remain stable at relatively mild temperatures, but decomposes to graphite and nitrogen at temperatures above 600-700 degrees C and up to 15 GPa, while it decomposes directly to diamond (plus nitrogen) above 800-900 degrees C and between 22 and 25 GPa. The estimated decomposition curve for g-C3N4 has a positive slope (similar to 0.05 GPa/K) up to similar to 22 GPa, but becomes inverted (negative) above this pressure. The diamond formed through decomposition is characterized by euhedral crystals which are not sintered to each other, but loosely aggregated, suggesting the crystallization in a liquid (nitrogen) medium. The nitrogen release from the graphitic C - N framework may also play an important role in lowering the activation energy required for diamond formation and enhancing the grain growth rate. No phase transition of g-C3N4 was found in the studied P-T range. (C) 2011 Elsevier B.V. All rights reserved.