【作者】 张滨；

【导师】 才庆魁； 成会明；

【作者基本信息】 东北大学 ， 材料学， 2006， 博士

【摘要】 当人们所熟知的块体材料至少有一维缩小到纳米尺度时，材料本身的性能，如电学、力学、光学、磁学以及化学性质便产生奇异的变化。因此低维材料的制备、微结构及其性能的研究一直是材料领域、凝聚态物理和材料化学等领域的前沿课题和研究热点。本文以多功能碳材料为代表，研究了零维热解碳球、一维纳米碳管以及碳的其它纳米结构的制备、微结构及其性能。二维材料选取了具有高导电性和低电迁移性的金属铜薄膜以及计算机硬盘用镍—磷非晶薄膜作为研究对象，研究了薄膜材料在单向和循环加载下的力学性能及其尺寸效应。 在不使用催化剂的条件下热解四氢呋喃，制备出表面光滑、圆整度高、球形度高、分散性好的实心碳球。同时研究选用芳香族化合物和具有介于芳香族和脂肪族化合物之间特征的液态化合物作为液体碳源，控制作为载气和稀释气体的种类、流量和混合比例，在不同的热解温度下合成出直径为100 nm～1 μm的热解碳球，并对这类碳球的微结构进行了系统的研究。研究表明：碳球的表面和心部分别具有两种不同的结构，碳球心部是由不发达的螺旋壳核心组成，其表面是不连续的略带弯曲的石墨烯碎片近似同心堆叠而成的结构。经2100℃石墨化处理后，心部不发达的螺旋结构转变成发达的螺旋壳结构，X射线衍射谱图在26.42°的肩膀头峰证实了心部特殊晶体结构的存在，热重分析和高分辨电镜观察证实了心部螺旋壳结构的存在，经2900℃高温石墨化处理后，螺旋壳核心转变成连续封闭的多面体次生壳，而碳球表面不连续的石墨烯碎片转变成不连续的多面体表面壳。通过热力学计算获得了碳球石墨化处理后发生微结构演化所遵循的尺寸效应，发现石墨化后转变的多面体壳距离核心越近，壳的厚度越薄；当碳球的半径大于临界半径时，碳球发生多面体转变在能量上是有利的，对于次生壳来说，任何尺寸的核心转变成六边形在能量上都是有利的。同时尝试将热解碳球及其石墨化后碳球作为锂离子电池负极材料进行了实际充放电实验，发现石墨化后的碳球有望作为锂离子电池负极材料使用。 通过对制备条件进行优化，选择原料液体中二茂铁最佳浓度为1.995wt％的乙醇溶液，通过流动催化法制备出被填充碳管比率高且管壁石墨化度高的管内填充一维铁单晶的纳米导线。从高分辨电镜像测量发现：管内填充的一维铁单晶纳米线的最密排面的晶面间距为0.198±0.001 nm，与公式计算的铁(101)面的面间距最为接近，同时X射线衍射分析结果也表明该铁单晶纳米线具有<101>晶体学方更多还原

【Abstract】 The properties of materials electronic, mechanical, optical, magnetic and chemical will change curiously when at least one of three dimensions of bulk materials decreases down to nano-scale. The investigations of synthesis, microstructures and properties of low-dimensional materials have been frontier fields and hot research topics in materials science, condensed physics and materials chemistry. In this dissertation, carbon, as a multi-functional material, was employed to investigate the synthesis, microstructure and their properties of zero-dimensional pyrolytic carbon spheres, one-dimensional carbon nanotubes and new carbon structures. For two-dimentional materials, thin copper films with high conductivity and low electromigration and Ni-P amorphous thin films used in computer harddisks were selected. The mechanical properties of the thin films subjected to monotonic and cyclic loading were investigated to elucidate the size effects.Solid carbon spheres with a smooth surface, almost perfect round shape and monodispersity were synthesized by pyrolysis of tetrahydrofuran without using any catalysts. The aromatic compounds and those with some characteristics intermediate between aromatic and aliphatic were selected to be carbon source, and the synthesis methods of pyrolytic carbon spheres were investigated as well. The carbon spheres with diameters of 100 nm to 1 μm were synthesized by using different carrier gases, controlling the flow rates and the proportions of the carrier gas. The microstructures of the carbon spheres were systematically investigated by scanning electron microscope, high-resolution transmission electron microscope (HRTEM), X-ray diffraction and Raman spectroscopy, etc. The results indicate that the spheres consist of an underdeveloped spiral-shell core and a surface with discrete fragments of concentrically arranged graphene layers. The underdeveloped spiral-shell structure changes into a well developed spiral-shell structure after heat treatment at 2100 ℃. The appearance of the shoulder peak at 26.42° in the pattern of X-ray diffraction confirms the presence of a special crystal structure in the core part of the spheres. Thermogravimetric analysis and the HRTEM observations of carbon sphere surfaces demonstrate the presence of the spiral-shell structure. It is found that the spiral-shell core transforms into continuous更多还原