磁控溅射法制备非晶碳膜及其光学特性

利用射频磁控溅射法成功制备了类金刚石薄膜,研究了溅射功率和基片温度对所沉积薄膜的的影响,对所制备的类金刚石薄膜用拉曼光谱、紫外光谱进行表征,所沉积的类金刚石碳薄膜是簇状分布的ＳＰ＾２碳键和网状分布的ＳＰ３碳键互相随机交织的一起的非晶 研究了非晶碳膜的光学性质和电学性质,探索了制备各种不同带隙非晶碳膜的工艺条件,为该类的实际应用提供了可靠的实验依据。     

射频PECVD方法生长含氢非晶碳膜的结构及摩擦学性能

利用射频等离子体增强化学气相沉积技术在不锈钢表面制备了含氢非晶碳膜.采用Raman光谱、红外光谱、X射线光电子能谱和原子力显微镜等研究了薄膜的微观结构和表面形貌,在栓盘摩擦磨损试验机上考察了薄膜在不同载荷与滑动速度下的摩擦学性能.结果表明:所制备的含氢非晶碳膜具有典型的类金刚石结构特征,薄膜均匀、致密,表面粗糙度小;薄膜与不锈钢球对磨时显示出良好的抗磨减摩性能;薄膜的抗磨减摩性能同对磨件表面上形成的转移膜以及摩擦过程中薄膜结构的石墨化相关.     

金刚石膜和氢化非晶碳膜电阻率测量的对比研究

对金刚石膜和氢化非晶碳膜的电阻率测试方法进行了对比研究，即对金刚石膜采用“大”尺度电极，氢化非晶碳膜采用“大”尺度电极和小尺度电极测量I－V曲线进行对比分析和讨论，得出了有意义的结果。     

氢化非晶碳膜的制备及其在金属表面防护上的应用

氢化非晶碳膜具有硬度高、电绝缘、光学透明、化学性能稳定等优良特性,又称为“类金刚石”碳膜。本文报导由碳氢气体的辉光放电分解而制备的氢化非晶碳膜的特性及其在金属表面防护上的应用。     

非晶态碳的结构：碳链的存在

对非晶碳的结构在某此低密度下是否有二度配位（ｓｐ．链状结构）的存在目前仍然存在争议，在用两种都相当精确的理论方法（Ｃａｒ－Ｐａｒｒｉｎｅｌｌｏ和紧束缚的分子动力学方法）研究密度约为２ｇ／ｃｍ￣３的非晶碳结构时，对是否有碳链的存在给出完全不同的结论，本文利用第一原理的自治赝势平面波方法，计算了一维ｓｐ碳链，二维ｓＰ￣２石墨和三维ｓｐ￣３金刚石结构的结合能、键长等性质随平面波数目的变化，澄清了两个理论结果的矛盾，支持了非晶碳在密度约为２ｇ／ｃｍ￣３时应有碳链存在的结论．     

放电电压对直流热阴极制备金刚石厚膜的影响

利用直流热阴极辉光放电方法制备出了高品质金刚石厚膜,生长速率达到20μm/h,生长厚度达到3mm.为了解其工作特性、优化沉积工艺,本文研究了放电电压对金刚石沉积速率和品质的影响.通过对扫描电镜、拉曼谱和XRD图谱分析得出,随着放电电压的增加,沉积速率呈下降趋势,电压在850～950V范围金刚石中石墨和非晶碳明显减少,晶粒均匀,表面晶向以(110)为主,金刚石薄膜的质量显著提高.     

直流辉光放电等离子体增强化学气相法制备金刚石及氮化碳薄膜

采用直流辉光放电等离子体增强化学气相沉积(PECVD)技术方法 ,在Si(100)衬底上制备了金刚石薄膜 ,并在此基础上合成了含有少量晶态颗粒的非晶氮化碳薄膜     

离子轰击碳膜诱导碳纳米尖端的形成和生长

用CH4、NH3和H2为反应气体,利用等离子体增强热丝化学气相沉积系统在沉积有碳膜的Si上制备了碳纳米尖端.用扫描电子显微镜、原子力显微镜和Raman光谱表征了碳膜的结构,以及用扫描电子显微镜和X射线光电子谱表征了碳纳米尖端的结构,结果表明碳膜是凸凹不平的非晶碳膜,碳纳米尖端是由sp2结构的碳组成.根据有关离子的溅射和沉积机制,分析了离子轰击碳膜诱导碳纳米尖端的形成和生长.     

采用磁过滤MEVVA源制备DLC膜的研究

采用磁过滤MEVVA沉积技术以石墨为阴极在几种衬底表面(单晶硅、不锈钢和工具钢等)上制备高质量类金刚石(DLC)薄膜.实验结果表明,沉积能量对薄膜的sp3键含量的影响为先随能量的增加而增加,达到最大值后,再增加沉积能量含量反而下降.硬度测试结果表明,非晶金刚石薄膜具有极高的硬度,为70～78GPa,远远高于衬底材料的硬度值.对非晶金刚石薄膜的摩擦性能试验结果表明,非晶金刚石薄膜的摩擦因数为0.16～0.2,大大低于衬底材料.     

爆轰过程中游离碳的状态研究

目的 研究高密度负氧平衡炸药爆轰过程中游离碳的状态。方法 结合爆轰合成纳米金刚石数值结果以及对固相爆轰产物的实验研究,对爆轰过程中游离碳的状态进行讨论。用具有明确物理意义和纯石墨,金刚石,超微金刚石和类液碳的状态方程对多种炸药的爆速进行计算。结果与结论 用超微金刚石和类液碳的状态方程比用纯石墨和金刚石的状态方程预报的炸药爆轰参数更接近实验值,证明高密度负氧平衡炸药爆轰时ＣＪ点上游离碳主要是以液态或     

活性碳,碳黑,石墨与金刚石晶种的生长

介绍了活性碳、碳黑与石墨在过剩压驱动下金刚石晶种的生长．对两种无定形碳以及石墨在触媒中的分散溶解输运与再结晶进行了观察，对活性碳、碳黑在金刚石晶种生长中的机理作了探索性的讨论．三种碳片上的晶种均有明显长大，无定形碳作晶种生长的碳源是可行的     

Superconductivity in diamond

Diamond is an electrical insulator well known for its exceptional hardness. It also conducts heat even more effectively than copper, and can withstand very high electric fields. With these physical properties, diamond is attractive for electronic applications, particularly when charge carriers are introduced (by chemical doping) into the system. Boron has one less electron than carbon and, because of its small atomic radius, boron is relatively easily incorporated into diamond; as boron acts as a charge acceptor, the resulting diamond is effectively hole-doped. Here we report the discovery of superconductivity in boron-doped diamond synthesized at high pressure (nearly 100,000 atmospheres) and temperature (2,500-2,800 K). Electrical resistivity, magnetic susceptibility, specific heat and field-dependent resistance measurements show that boron-doped diamond is a bulk, type-II superconductor below the superconducting transition temperature T(c) approximately 4 K; superconductivity survives in a magnetic field up to Hc2(0) > or = 3.5 T. The discovery of superconductivity in diamond-structured carbon suggests that Si and Ge, which also form in the diamond structure, may similarly exhibit superconductivity under the appropriate conditions.     

Effect of additive boron on type-Ib gem diamond single crystals synthesized under HPHT

The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR)...     

Diamond synthesis from a system of chromium-carbide and Ni70Mn25Co5 alloy

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2 powder and Ni 70Mn 25Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 20, 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2 decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.     

大面积CVD金刚石膜的热铁板抛光

研制成功国内第1台大面积CVD金刚石膜热铁板抛光机,它可以在10^-3pa真空条件下,加热到1100℃;抛光台可以在0－10r/min间实现无级调速,一次完成3片φ110mm的金刚石膜的抛光,金刚石膜在980℃,2h抛光的结果表明该装置有良好的抛光效果。金刚石膜在980℃抛光不同时间的Raman谱表明,金刚石热铁板抛光是金刚石石墨化和C原子不断扩散的过程。     

Mechanism of diamond-to-graphite transformation at diamond-stable conditions

The diamond-to-graphite transformation at diamond-stable conditions is studied by temperature gradient method （TGM） under high pressure and high temperature （HPHT）, although it is unreasonable from the view of thermodynamic considerations. It is found that, at diamond-stable conditions, for example, at 5.5 GPa and 1550 K, with fine diamond grits as carbon source and NiMnCo alloy as metal solvent assisted, not only large diamond crystals, but metastable regrown graphite crystals would be grown by layer growth mechanism, and the abundance of carbon source in the higher temperature region is indispensable for the presence of metastable regrown graphite crystals. From this transformation, it is concluded that, with metal solvent assisted, although the mechanism of crystal growth could be understood by the macro-mechanism of solubility difference between diamond and graphite in metal solvents, from the point of micro-mechanism, the minimum growth units for diamond or graphite crystals should be at atomic level and unrelated to the kinds of carbon source （diamond or graphite）, which could be accumulated free-selectively on the graphite with Sp2Tr or diamond crystals with sp3 bond structure.     

火焰法沉积金刚石薄膜的组织结构

用透射电镜（ＴＥＭ）对大气中火焰法沉积（ＣＦＤ）金刚石薄膜的组织结构进行了分析研究。结果表明，所沉积的金刚石晶体中（１１１）面上存在着大量层错及显微孪晶，在（１１１）面上晶粒边界处的位错密度较低，此外，在金刚石薄膜中还观察到存在于金刚石颗粒间的非金刚石型碳（Ｃ），即无定形碳及微晶石墨。     

Gas and pressure effects on the synthesis of amorphous carbon nanotubes

The effects nf gas. pressure and temperature on the production of amorphous carbon nanotubes were investigated using an are discharging furnace at controlled temperature. Co/Ni alloy powder was used as catalyst. The discharge current was 80 A and voltage was 32 V The optimal parameters were obtained: 600℃ temperature, hydrogen gas and 500 torr pressure. The productivity and purity of amorphous carbon nanotubes are 6.5 gram per hour and 80%, respectively. The diameter of the amorphous carbon nanotubes is about 7—20 nm.     

Analysis of the carbon source for diamond crystal growth

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.