片状h-CN化合物的高温高压化学合成与表征

 以高温烧结三聚氰胺制得的CNH化合物为C、N源，与分析纯单质硼粉以一定比例混合，在5.0～5.5 GPa、1 400~1 500 ℃高温高压条件下，经化学反应合成了六角硼碳氮（h-BCN）晶体。用傅立叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）对产物进行了表征，结果表明，得到了含碳量较高的六方结构B_0.18C_0.66N_0.16化合物，成分接近于BC₄N，硼、碳、氮是以原子化合的形式存在；XRD分析确定该合成产物具有六角网状结构；SEM测量结果表明，B-C-N晶体具有片状六角形貌，尺寸在1 μm左右。     

Synthesis of Cubic Boron Nitride by the Reaction of Li3N and B2O3

Cubic boron nitride is synthesized by the reaction of Li3N and B203 under high pressure and high temperature （4.0-5.0 GPa, 1350-1500℃）. The minimum pressure of cBN formation is 4.0 GPa. The present condition of cBN formation is clearly lower than the eutectic temperature of Li3BN2 and BN in the Li3N-hBN system （5.5 GPa, 1610℃）. The content of cBN in the sample increases, while the content of hBN decreases with the temperature and pressure. The maximum conversion rate （5.0 GPa, 1500℃） is about 34%, which is higher than that in the hBN-Li3N system. The cBN crystals are octahedral or tetrahedral in shape and approximately 20 μm in diameter.     

高压高温下B2O3与Mg和Li3N的反应

 通过B₂O₃与Mg和Li₃N分别在不同温度压力条件下的反应，用X射线方法研究了生成物的物相。当采用Mg与B₂O₃为原料时，其产物是Mg₃B₂O₆；用Li₃N与B₂O₃反应时，产物中除了Li₃BO₃，还有立方氮化硼（cBN）生成。这表明，当原料中含有相同数量B₂O₃时，用Mg和Li₃N分别作触媒合成立方氮化硼，将得到不同的结果。     

镁橄榄石和顽辉石的高温高压合成

 用国产六面顶压机，在温度为1 000～1 500 ℃和压力为2～5 GPa的高温高压条件下，对氧化镁（MgO）和二氧化硅（SiO₂）混合粉末样品进行了处理。通过对所得产物的观察与X射线衍射分析结果表明，在较宽的压力范围内，可以得到镁橄榄石（Mg₂SiO₄）单晶体和顽辉石（MgSiO₃）单晶体。讨论了地幔物质镁橄榄石（Mg₂SiO₄）和顽辉石（MgSiO₃）的生成条件、生长特性及相变关系。     

Growth Feature of Cubic Boron Nitride on c-BN Crystal Substrates

Cubic boron nitride （c-BN） films were deposited on highly-oriented （111） bulk c-BN crystal by using the rf magnetron sputtering method. The growth films are characterized by micro-Raman spectroscopy （μ-RS） and scanning electron microscopy （SEM）, The results show that the high crystallization electron transparent c-BN films in thickness of about 10μm are obtained, Island and step growth models are clearly shown.     

片状h-BCN化合物的高温高压化学合成与表征

以高温烧结三聚氰胺制得的CNH化合物为C、N源,与分析纯单质硼粉以一定比例混合,在5.0~5.5 GPa、1 400~1 500℃高温高压条件下,经化学反应合成了六角硼碳氮(h-BCN)晶体。用傅立叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对产物进行了表征,结果表明,得到了含碳量较高的六方结构B0.18C0.66N0.16化合物,成分接近于BC4N,硼、碳、氮是以原子化合的形式存在;XRD分析确定该合成产物具有六角网状结构;SEM测量结果表明,B-C-N晶体具有片状六角形貌,尺寸在1μm左右。     

用射频磁控溅射法在c-BN晶体基底上生长c-BN薄膜

本文用射频磁控溅射方法在片状c-BN晶体基底上生长了c-BN薄膜,显微拉曼光谱(μ-RS)和扫描电子显微镜(SEM)测试结果表明:沉积的薄膜是大约10μm厚、高结晶性、电子透明的高纯c-BN薄膜.岛状和层状生长模式在试验中清晰的展示出来.同时在生长的c-BN薄膜内部和被遮盖的基底部分上发现了籽晶.     

Chemical Synthesis and Characterization of Flaky h-BCN at High Pressure and High Temperature

Hexagonal boron carbonitrogen （h-BCN） compound is synthesized from a mixture of boron powder and CNH compound prepared by pyrolysis of melamine （CaH6N6） under high temperature （1400-1500℃） and high pressure （5.0-5.5 GPa）. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spec- troscopy are used to determine the chemical composition and bonds of the product. The results show that the product has composition of B0.18C0.64N0.16 （near BC4N） and atomic-level hybrid. X-ray diffraction analysis indicates that the powder has a hexagonal network structure. Scanning and transmission electron microscopy results suggest that h-BCN compound morphology is mainly flaky in width about 1 μm and thickness 200nm.