| 特集-ダイアモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,147-154(1998) |
| 放射光蛍光Ｘ線分析を用いる合成ダイヤモンドの不純物解析 Characterization of Impurities in Synthetic Diamonds by Using Synchrotron Radiation X-ray Fluorescence Analysis |
| 早川 慎二郎 賈 暁鵬* 合志 陽一 若槻 雅男* Shinjiro HAYAKAWA JIA Xiao-Peng Yohichi GOHSHI Masao WAKATSUKI |
| Trace impurities in synthetic diamonds are characterized by using a scanning x-ray microprobe with synchrotron radiation. The diamond crystals analyzed were grown under high pressure and high temperature with the various metalic solvents. Utilizing synchrotron radiation (SR) x-ray fluorescence (XRF) analysis, concentrations of trace impurities down to 0.1 ppm can be evaluated. Moreover, the x-ray energy dependence of XRF yield around the absorption edge shows the near-edge x-ray absorption fine structure of the trace impurities, which provides chemical-state information on the trace impurities in the diamond crystal. The future expectation of analytical capability with the next generation synchrotron light source is also described. [diamond, x-ray fluorescence, impurity, synchrotron radiation, x-ray absorption fine structure] |
| 〒113-8656 東京都文京区本郷7-3-1 東京大学大学院工学系研究科応用化学専攻 Department of Applied Chemistry, The University of Tokyo, Hongo, Bunkyo, Tokyo 113-8656 *〒305-0006 つくば市天王台1-1-1 筑波大学物質工学系 Institute of Materials Science, Univ. of Tsukuba, Tsukuba, Ibaraki 305-0006, Japan |
| 特集-ダイアモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,155-162(1998) |
| 合成ダイヤモンドの不純物と光学特性 Impurities and Optical Properties of Synthetic Diamond |
| 神田 久生 Hisao KANDA |
| Pure diamond has no absorption bands in a wide range of wave lengths from ultraviolet to infrared. However, diamond crystals show some colors usually, although most of them are nonattractive yellow or brown. Diamond crystals also give off a variety of luminescence with stimulation from an electron beam, UV light, etc. The colors are produced by the incorporation of impurities. In the case of diamond, the impurities which are incorporated are limited. They are nitrogen, boron, nickel, cobalt, silicon and phosphorus. The color features of high pressure synthetic diamonds are described in terms of the impurities. [diamond, single crystal, impurity, optical property, optical absorption, luminescence, color, defect] |
| 〒305-0044 つくば市並木1-1 無機材質研究所 National Institute for Research in Inorganic Materials( NIRIM ), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 |
| 特集-ダイヤモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,163-170(1998) |
| ダイアモンド溶融相からの材料合成 Materials Synthesized from Molten Diamond |
| 都賀谷 素宏 Motohiro TOGAYA |
| Liquid carbon was formed by the melting of diamond and the metastable melting of graphite in the diamond stable regions at 15 and 18 GPa. The diamond crystallized by cooling the molten carbon was investigated by visible and ultraviolet absorption spectra, cathodoluminescence (CL) and transmission electron microscopy (TEM). The diamond contains nitrogen and is classified as Type I. The color centers of blue band A, green band A, H3, 575 nm and N3 were found and a vacancy-type dislocation loop and a cavity with a cuboctahedral shape were observed in the diamond. The solidification behaviors of a diamond from the molten C-BN and C-aluminosilicate are also discussed. [melting, metastable melting, graphite, diamond, liquid carbon, crystallization, absorption spectra, cathode luminescence, transmission electron spectroscopy, color center, dislocation loop, cavity, C-BN system, C-aluminosilicate system] |
| 〒560-8531 豊中市待兼山町1-3大阪大学 Osaka University, 1-3 Matikaneyama-cho Toyonaka 560-8531 |
| 特集-ダイアモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,171-176(1998) |
| ｃＢＮ単結晶の高圧合成 Synthesis of a cBN Single Crystal under High Pressure |
| 谷口 尚 Takashi TANIGUCHI |
| A single crystal of cubic boron nitride(cBN) was grown under the high-pressure and high-temperature conditions of 5.5 GPa and 1500-1700 for 10 min.-100 h. A temperature gradient method was employed for the crystal growth by using lithium boron nitride as a solvent. In order to characterize the growth features of cBN single crystal on seed surfaces, large seeds of diamond crystals were employed, and the heteroepitaxial growth of cBN on (100) and (111) diamond surfaces was studied. The initial growth feature of the cBN crystal was found on the diamond seed surface after a growing time of 10 min. On the (100) seed surface, typical anti-phase boundaries were exhibited in the grown crystals, while they were not seen in crystals grown on a (111) surface. Two types of growth features such as (111) and (113) facetted growth typically appeared in the grown crystal on the (111) surface. Considering the growth process under a constant P-T growing condition, the growth rate of cBN crystal was significantly small as compared to that of diamond. [cBN single crystal, diamond seed, temperature gradient method, heteroepitaxial growth, anti-phase boundary] |
| 〒305-0044 茨城県つくば市並木1-1 科学技術庁 無機材質研究所 National Institute for Research in Inorganic Materials, 1-1 Namiki Tsukuba, Ibaraki 305-044 Japan |
| 特集-ダイヤモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,177-184(1998) |
| B-C-N系物質の低圧相と高圧相の合成研究 Syntheses of Low-Pressure and High-Pressure Phases in the B-C-N System |
| 佐々木 高義 Takayoshi SASAKI |
| This article reviews recent progress in the syntheses of B-C-N ternary materials. A number of B-C-N graphites of various stoichiometry have been synthesized via chemical vapor deposition and pyrolysis of precursors. One of the typical compositions, BC2N, has been relatively well-characterized, revealing that it is a genuine B-C-N compound with a semiconductive nature with a bandgap around 2 eV. Static and dynamic compressions on the B-C-N graphites have been conducted to explore the phase relationship and stability of B-C-N high-pressure phases. The results from these studies can systematically be understood by the fact that segregation into diamond and cBN is thermodynamically favored rather than formation of a B-C-N diamond-like compound. [B-C-N ternary system, hybrid compounds, graphite-like materials, semiconductor, diamond-related phases, superhard materials] |
| 〒305-0044 茨城県つくば市並木1-1 科学技術庁 無機材質研究所 National Institute for Research in Inorganic Materials, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 |
| 特集-ダイアモンドの高圧合成- Rev. High Pressure Sci. Technol. 8-3,185-192(1998) |
| B-O系超硬物質の合成と焼結 Synthesis and Sintering of Super-hard Materials in the B-O System |
| 伊藤 秀章 Hideaki ITOH |
| A brief historical review of research concerning super-hard materials in the boron suboxide system is described with an emphasis on the synthesis and sintering of hexaboronoxide (B6O). Authors' investigations of the preparation of B6O-based super-hard materials are also described along with the formation behavior of B6O powder in a high temperature reaction between amorphous boron and B2O3. The structure and properties of the single phase B6O sintered compact obtained under high pressure are discussed in reference to the literature. The sintered composites in the B6O-B4C and B6O-cBN systems were prepared under high pressure and temperature conditions (3-6 GPa, 1500-1800℃). The mechanical properties (hardness and toughness) and chemical stability are related to the phase relationship in the above quasi-two component systems and the microstructures of sintered composites. [boron suboxide, high pressure sintering, super-hard boron compounds, sintered composites] |
| 〒464-8603 名古屋市千種区不老町名古屋大学理工科学総合研究センター Center for Integrated Research in Science and Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603 |
| トピックス Rev. High Pressure Sci. Technol. 8-3,193-208(1998) |
| 電子移動反応と高圧化学 Electron Transfer Reactions at Elevated Pressures |
| 高木 秀夫 HideoTAKAGI |
| The theory of outer-sphere electron tranfer processes has been developed by many scientists since the first publication by Libby in 1952 referring to the role of the solvent. After the establishment of Marcus Theory, the electron transfer reactions have been analysed on the basis of activation free energy, provided that the inner-sphere and outer-sphere changes are concerted. However, this approach was proved to be rather inaccurate because of the uncertainties in the estimation of the inner-sphere contribution to the activation free energy. A recent development of the analyses based on the volume profiles of reactions, however, proved that the more accurate interpretation of the outer-sphere electron transfer processes is possible as the uncertainty related to the inner-sphere contribution diminishes. Theoretical treatment and the application of the "volume analysis" to various outer-sphere reactions are summarized in this review, together with an application of the volume analysis to the "Gated" electron transfer processes. [electron transfer, theory and application, mechanism, activation volume, reaction volume, elevated pressure] |
| 〒464-8602 名古屋市千種区不老町 名古屋大学大学院理学研究科物質理学専攻無機・分析化学大講座 Inorganic and Analytical Chemistry Division, Department of Chemistry and Physics, Graduate School of Sciences, Nagoya University, Furocho, Chikusa-ku, Nagoya, 464-8602 Japan |
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