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Analysis of the carbon source for diamond crystal growth

Chinese Science Bulletin 2008年第6期53卷 937-942页

作者： LI Li1,2, XU Bin2,3 & LI MuSen1,2 1 School of materials Science & engineering, shandong University, Jinan 250061, china 2.shandong engineering research center for super hard materials, zoucheng 2.3500, china 3 School of materials Science & engineering, shandong Jianzhu University, Jinan 250101, china School of materials Science & engineering Shandong University Jinan China shandong engineering research center for super hard materials Zoucheng China School of materials Science & engineering Shandong Jianzhu University Jinan China

The lattice constants of diamond and graphite at high pressure and high temperature (HPHT) were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng (TFDC). It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.

关键词：钻石晶体生长石墨碳源价电子结构

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Valance electron structure of carbide-diamond interface and catalytic mechanism for diamond synthesis under high-pressure and high-temperature

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Progress in Natural Science:materials International 2006年第8期16卷 852-858页

作者： GONG Jianhong, XU Bin, YIN Longwei, QI Yongxin, LI Li, SU Qingcai and LI Musen (School of materials Science and engineering, shandong University, Jinan 250061, china Department of materials Science and engineering, shandong Institute of Architecture and Technology, Jinan 250014, china shandong engineering and Technology research center of super-hard materials, zoucheng 2.3500, china) [a]School of materials Science and engineering Shandong University Jinan China [b]shandong engineering and Technology research center of super-hard materials Zoucheng China [c]Department of materials Science and engineering Shandong Institute of Architecture and Technology Jinan China

The metallic films surrounding a synthetic diamond formed under high-pressure and high-temperature (HPHT) in the presence of Fe-based and Ni-based catalysts were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was showed that the carbide was the primary carbon source for the nucleation and growth of diamond. Based on the EET (empirical electron theory in solid and molecules) theory, the valence electron structure of interface between carbide (Fe3C, Ni3C, (Fe, Ni)3C) and diamond was calculated using the bonding length difference (BLD) method. The boundary criterion of Thomas-Fermi-Dirac-Cheng (TFDC): "the electron density being equal on the contacting surfaces of atoms" was applied to analyze the valence structure of carbide-diamond interface. The result based on the calculation valance electron structure is in good accordance with the experimental result. This study is very helpful to reveal the catalytic mechanism of diamond nucleation and growth and design the new catalyst for diamond synthesis.

关键词： synthetic diamond carbide catalytic mechanism valence electron theory interface.

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Mist-jetting Electrical Discharge Dressing Technology for superabrasive Grinding Wheels

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Journal of Shanghai Jiaotong university(Science) 2008年第6期13卷 712-716页

作者：蔡兰蓉胡德金贾妍 School of Mechanical and Power engineering Shanghai Jiaotong UniversityShanghai 200030China

The technology of superabrasive grinding has been developed in order to achieve high-quality finish in extremely hard and brittle ***, truing and dressing technology on super abrasive grinding wheel is one of the most important subjects on precise machining field at *** this paper, mist-jetting electrical discharge technology was applied to dressing metal-bonded superabrasive *** a systematical study on the mechanism of selective removal of the bond was *** on dressing bronze bonded diamond grind wheels were carried out on a die-sinking electrical discharge *** diamond wheel topographies before and after electrical discharge dressing were observed by VH-800 3D digital *** wheel profiles before and after dressing were *** results of electrical discharge dressing under different electrical parameters were *** results indicate that the favorable surface topography can be obtained under suitable processing parameters and mist-jetting electrical discharge dressing(MEDD) is feasible for metal-bonded diamond grinding wheel.

关键词： dressing superabrasive grinding wheel mist-jetting electrical discharge

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冰箱用HIPS的增韧改性研究

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山东化工 2011年第12期40卷 32-34,38页

作者：冯玉敏耿瑞芝牟岩蕾郝际臣青岛科技大学塑料材料与工程教育部重点实验室山东青岛266042 青岛职业技术学院化工技术教研室山东青岛266555 青岛宏达塑胶总公司技术中心山东青岛266109

以高抗冲聚苯乙烯(HIPS)为基体树脂,用螺杆挤出的方法研究了一系列增韧剂对HIPS的增韧效果,结果表明乙烯丙烯酸甲酯(EMA)对HIPS的增韧效果较为明显,当体系中EMA含量达到20份时,所制得超韧HIPS材料具有最优异的综合性能。并进一步用增韧... 详细信息

以高抗冲聚苯乙烯(HIPS)为基体树脂,用螺杆挤出的方法研究了一系列增韧剂对HIPS的增韧效果,结果表明乙烯丙烯酸甲酯(EMA)对HIPS的增韧效果较为明显,当体系中EMA含量达到20份时,所制得超韧HIPS材料具有最优异的综合性能。并进一步用增韧后的HIPS进行挤出生产实验,发现增韧后的聚苯乙烯在板材生产加工过程中与HIPS相比,其工艺生产条件及加工后的板材性能基本没有发生变化。

关键词：高抗冲聚苯乙烯共混增韧改性

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