利用甲烷/氢微波等离子体CVD工艺在纯钛基底上沉积纳米金刚石薄膜

与微米金刚石薄膜不同，纳米金刚石薄膜表面平滑。因此，在摩擦学应用领域中，纳米金刚石薄膜是最理想的。表研究利用CH4／H2微波等离子体CVD工艺在纯钛上沉积出纳米金刚石薄膜和微米金刚石薄膜。采用的沉积条件为：沉积温度约为1173K；沉积压力为8．0kPa；CH4浓度在0．5mol％和5mol％之间变化；沉积时间则从4h到12h不等。金刚石薄膜表面用扫描电镜（SEM）观察。在激光拉曼光谱中，微米金刚石薄膜在1332cm^-1处有sp^3键碳的锐峰。1140cm^-1附近的光谱带与纳米金刚石薄膜的特征有关。并用X射线衍射对金刚石薄膜进行了分析。X射线衍射花样证实，纳米金刚石薄膜存在（111）面和（220）面。金刚石薄膜的表面粗糙度随着CH4浓度的增加而减小。但是，甲烷浓度在2mol％与5mol％之间变化时，金刚石薄膜的表面粗糙度接近50nm。据证实，CH4浓度在2mol％和5mol％之间，利用CH4／H2微波等离子体CVD工艺可以沉积出纳米金刚石薄膜。     

Mimicking Nanometer Atomic Processes on a Micrometer Scale via Electrophoretic Deposition

The process of submonolayer formation during the electrophoretic deposition (EPD) of colloidal films of micrometer-sized (diameter ∼ 0.5 μm) silica particles on a silicon wafer has been observed as a function of deposition time. The process of nucleation and growth of the silica monolayer is compared with that of atomic film growth (10000 times smaller scale) via molecular-beam epitaxy (MBE), and for the first time, a striking similarity between the two growth processes is observed. Likewise in the atomic growth process via MBE, the entire nucleation, growth, and aggregation process during EPD of silica particles can be broadly classified into two regions. At low surface coverage when silica particles are deposited outside of clusters, diffuse randomly, and stick to a cluster on touching them, the mechanism of growth in this region follows diffusion-limited aggregation (DLA) and the fractal dimension of the two-dimensional clusters is found to be close to 1.65. Later on, as the clusters grow in size, deposition of particles inside the clusters become important and clusters become more and more compact, resulting in a dense, close-packed, and homogeneous monolayer. This region is termed a consolidation region, and a change in fractal dimension from 1.65 toward 2 with increasing surface coverage has been observed.     

聚苯胺/氧化锌复合膜的制备及其防腐性能

将化学氧化法制备的聚苯胺(PANi)粉末溶于氮甲基吡咯烷酮溶剂后涂覆到制备有ZnO底层的碳钢基体上,获得了PANi/ZnO复合膜。通过扫描电镜、X射线衍射、极化曲线、电化学阻抗谱等测试手段分析了PANi/ZnO复合膜的形貌、成分、与基体的粘附力强度及在3.5%NaCl溶液中的耐腐蚀性能。结果表明,在碳钢基体上制备的PANi/ZnO复合膜中的ZnO呈纳米棒状,提高了复合膜的均匀性和表面平整性,增强了复合膜与金属基体的粘附力。与裸碳钢片相比,有复合膜层的试样的开路电位正向偏移180mV左右,自腐蚀电流密度降低。PANi/ZnO复合膜有效提高了碳钢基体的防腐性能。     

Atomic structure of fivefold twin center in diamond film

Atomic resolution high voltage transmission electron microscopy (ARHVTEM) was applied to a fivefold twin center in diamond film. The atomic structure of the fivefold twin center was the same as that suggested by Matsumoto and Matsui. The structure had no dangling bond. The fivefold-membered ring was observed to be at the center. The location of the fivefold twin center, observed in this study, indicated that it was produced by the meeting of two {111} Σ3 grain boundaries.     

ZnO薄膜的制备及光催化性能研究

采用溶胶 凝胶法在石英玻璃基底上制备出性能优良的ZnO薄膜。并通过XRD、AFM和UV VIS吸收光谱对薄膜的结构及形貌进行表征,研究了降解温度、苯酚溶液的初始浓度和空气流量对ZnO薄膜光催化性能的影响,ZnO薄膜光催化降解苯酚的最佳条件：降解温度25～45 ℃,空气流量40 mL·min^－1。起始浓度越低,降解效果越显著,同时实现了ZnO薄膜催化剂的固载,催化效果显著。同时研究了ZnO薄膜催化剂的固载。固载后的ZnO薄膜催化剂催化效果显著,且便于回收利用。     

纳米ZnO改性聚酯抗凝血性能研究

采用原位聚合方法制备了纳米ZnO/聚酯复合物,采用热压成膜和溶液法成膜两种方法将其制膜,利用动态凝血实验研究了纳米ZnO添加量及成膜方法对聚酯抗凝血性能的影响。结果表明,溶液法成膜的薄膜抗凝血性能优于热压法成膜。含有纳米ZnO的聚酯薄膜的抗凝血性能优于纯聚酯薄膜。随着纳米ZnO的加入量不断增加,聚酯薄膜的抗凝血性能先增加后减少。     

Nanometer rough,sub-micrometer-thick and continuous diamond chemical vapor deposition film promoted by a synergetic ultrasonic effect

In this paper we report on a surface treatment to seed substrates for the promotion of diamond nucleation. This surface treatment consists of an ultrasonic abrasion process using poly-disperse slurry composed of a mixture of small diamond particles (<0.25 μm) and larger particles (>3 μm) which may consist of diamond, alumina, titanium, etc. Whereas ultrasonic abrasion with a mono-disperse diamond slurry results in a diamond nucleation density of ∼2–3×10⁸ particles/cm², treatment with poly-disperse slurries results in diamond nucleation density of values up to ∼5×10¹⁰ particles/cm². This effect was found to display a similar effectiveness on a variety of substrates such as silicon, sapphire, quartz, etc. The enhancement in diamond nucleation is interpreted by a ‘hammering’ effect whereby the larger particles insert very small diamond debris onto the treated surface, thus increasing the density of nuclei onto which diamond growth takes place during the chemical vapor deposition process. By increasing the nucleation density to values of ∼5×10¹⁰ particles/cm², continuous diamond films of thickness of less than ∼100 nm were grown after only 5 min of deposition. The roughness of continuous diamond films grown on substrates treated at optimum conditions obtains values of 15–20 nm. The effect of ultrasonic treatment on silicon substrates and the deposited films was investigated by atomic force microscopy (AFM), high-resolution scanning electron microscopy (HR-SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.     

Synthesis of diamond nanocrystals on polyimide film

Sulfur-assisted hot-filament chemical vapor deposition (HFCVD) was recently employed to grow diamond nano-crystals on polyimide film [F. Piazza, G. Morell, Diamond and Related Materials, 16 (2007) 1950], unambiguously showing that the substrate temperature was below 360 °C, the polyimide glass transition temperature. This accomplishment has opened the door to employ diamond in a wide range of applications where it needs to be integrated with temperature sensitive materials. The result reported earlier relies on visible Raman spectroscopy analysis. We hereby report new additional evidences confirming the result from transmission electron microscopy (TEM), high-resolution TEM, energy dispersive X-ray analysis, electron energy loss spectroscopy and selected area electron diffraction.     

CVD金刚石膜投资财务分析

文章从经济的角度,通过专业的财务分析,对CVD金刚石膜这一新型材料的投资价值进行研究。研究认为,CVD金刚石膜将成为金刚石材料未来发展的主流,其材料和制品具有广阔的市场前景。因此,投资CVD金刚石膜将获得丰厚的经济回报。     

Precursors of copper/zinc oxide catalysts

Recent results on hydroxycarbonate precursors of copper/zinc oxide catalysts for methanol synthesis are reinterpreted, taking into account earlier work on these systems. This revised version was published online in July 2006 with corrections to the Cover Date.