Microtextures of synthetic diamond by Shock Compresion, Chemical Vapor Deposit, and Statick Compression and Origin of Cosmic diamond.

通过冲击压缩、化学气相沉积和静态压缩合成金刚石的微观结构以及宇宙金刚石的起源。

• 批准号: 06640612
• 负责人: YAGI Hisako
• 金额: $ 1.28万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640612/
• 关键词: Cosmic diamond; Synnthetic diamond; microtectures; shock compression; Chemical Vapor Deposit; Static compression; 成因

Predominant parameters in the shock-induced transition from graphite materials to diamond were examined in the present study by using quenching and powder methods under pressures of 50 to 60 GPa and 80 to 90 GPa, respectively, in the temperature range from 750 to 3500 K.Effects of the material parameters of the starting graphite-i.e., crystallite size and crystallinity-were distinguished from effects of the experimental parameters by standardizing the shock conditions for the materials examined. In addition, only a few graphite materials possessing wholly identical parameters throughout were selected as starting materials.Detailed characterization by transmission electron microscopy and electron energy-loss spectroscopy revealed that the transition ratios of diamond and the degrees of graphitization varied with those parameters. The various changes observed were plotted in terms of pressure, temperature, and material-parameter axs to create a tentative Pressure-Temperature-Material dia … More gram representing the behavior of the graphite materials under shock compression. The material parameters of the initial graphite structure primarily affected the diamond transition : The lower the crystallinity and crystallite size, the more easily the diamond transition occurred in the case of a reconstructive mechanism. Smaller crystallite size and lower crystallinity elevated the initial energy states of the graphite materials because of surface energy and strain energy, making it relatively easier to transcend the activation-energy barrier to diamond transition. Temperature was fairly effective and pressure ineffective in regard to the diamond transition, a result consistent with the belief that the transition is a diffusion-controlled process. Moreover, differentiation of the transition pathways, the diamond transition, and graphitization fit a concept of alternative metastable behavior ; graphitization was more favored kinetically than diamond transition under the shock conditions examined. Less

在750~3500K的温度范围内，用淬火法和粉末法分别在50~60 Gpa和80~90 Gpa的压力下研究了冲击诱导石墨材料向金刚石转变的主要参数。通过标准化所考察材料的冲击条件，区分了起始石墨的材料参数--微晶尺寸和结晶度--的影响。此外，只选择了几种参数完全相同的石墨材料作为起始材料，通过透射电子显微镜和电子能量损失谱的详细表征表明，金刚石的过渡率和石墨化程度随这些参数的变化而变化。根据压力、温度和材料参数AXS绘制了观察到的各种变化，以创建暂定的压力-温度-材料直径…更多的克代表石墨材料在冲击压缩下的行为。初始石墨结构的材料参数主要影响金刚石的转变：结晶度和微晶尺寸越低，在重构机制下越容易发生金刚石转变。较小的微晶尺寸和较低的结晶度，由于表面能和应变能的存在，提高了石墨材料的初始能态，使其相对容易跨越活化能势垒向金刚石转变。对于钻石的转变，温度是相当有效的，而压力是无效的，这一结果与认为转变是扩散控制的过程的信念一致。此外，转变路径的分化、金刚石转变和石墨化符合交替亚稳态行为的概念；在所考察的冲击条件下，石墨化在动力学上比金刚石转变更有利。较少

项目成果

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Hirai,H. 和 Kondo,K.：“从 C_<60> 富勒烯到 sp3 无定形的电子状态和结构的变化” Phys。

Hirai, H. , Tabira, Y.: "Radial distribution function of amorphous diamond shock-induced from C_<60> fullerene." Phys. Rev. B. 52. 6162-6165 (1995)

Hirai, H.、Tabira, Y.：“由 C_<60> 富勒烯引起的非晶金刚石冲击的径向分布函数。”

Hirai, H. , Kukino, S.: "Predominant Prameters in Shock-Induced Transition from Graphite to Diamond" J. Appl. Phys.78. 3052-3059 (1995)

Hirai, H.、Kukino, S.：“冲击引起的从石墨到金刚石转变的主要参数”J. Appl。

Hirai,H.,Kukino,S.,: "Dependence of diamond reansition on microtexture in starting materials under shock compression." J. Am. Ceram. Soc.78. 2079-2084 (1995)

Hirai,H.,Kukino,S.，：“冲击压缩下金刚石的转变对起始材料微观结构的依赖性。”

Hirai, H., & Kondo, K.: "Amorphous diamond from C_<60> fullerene by shock compression and rapid quenching." High-Pressure Science and Technology-1993, Edited by S.C.Schmidt, J.W.Shaner, G.A.Samara, M.Ross, AIP Press. 659-662 (1994)

平井，H.，