【作者】 袁海龙；

【导师】 凤仪；

【作者基本信息】 合肥工业大学 ， 材料学， 2004， 硕士

【摘要】 传统银-石墨电刷材料是一种很好的电接触材料，但随着石墨含量的增加，虽然润滑性能增加但其相对密度、硬度、导电性能都直线下降，已很难满足现在各种复杂情况下的应用，因此需要采用一种新的方法或材料来代替石墨，即起到润滑的作用又可增强、导电导热。自lijima发现碳纳米管以来，碳纳米管受到广泛的关注，其优异的力学性能、弹性模量、长径比、导电导热性能是理想的复合材料增强体。 本文首先研究了烧结工艺温度参数对复合材料的力学性能和电学性能的影响，以得到最佳的烧结工艺。在此基础上研究了碳纳米管含量的变化对复合材料的力学性能和电学性能的影响。结果表明：在复压后复合材料可以达到比较致密的程度；在碳纳米管体积含量小于11％时，碳纳米管可以提高复合材料硬度，且复合材料的电导率较高：碳纳米管体积含量大于11％以后，因为碳纳米管发生团聚，导致相对密度下降、电阻率上升。由于碳纳米管与基体的界面结合强度低，使复合材料抗弯强度下降。 通过化学镀在碳纳米管表面镀覆一层纳米级的金属，增加碳纳米管与基体的界面结合强度和提高碳纳米管的分散性，以改善复合材料的性能。因为碳纳米管尺寸小，曲率大，易缠结，要想在其表面进行化学镀比较困难。通过研究，发现经过研磨、氧化、敏化、活化后，可以提高碳纳米管表面的活性，通过改进镀液成分，pH值以及温度等，使沉积的速度尽可能的低。最终在碳纳米管表面镀覆一层比较均匀的铜层和银层，为碳纳米管／银复合材料性能的进一步改善打下了基础。 将化学镀后的碳纳米管用于复合材料中，研究其性能的变化发现在碳纳米管化学镀后，可以使复合材料的硬度、导电性增加，且可使复合材料的抗弯强度增强。讨论了复合材料界面的应力传递机制以及断口的破坏机制，更多还原

【Abstract】 The traditional Ag/graphite electrical brush is a kind of excellent electrical contact material. With the increase of the content of graphite, though the properties of lubrication may be increased ,the properties of mechanical and electrical are linear decrease. The applications will be very difficulty in complicated environment . So we must find replaceable materials ,which not only act as lubrication but also as enhancements and conductivity. Since Iijima found carbon nanotube,it attract extensive attention, for excellent elastic modulus ,low friction mechanical and electrical properties. So it are thought as perfect fiber-like enhancements. First we study technics influence to mechanical and electrical properties, and get better sinter technics. On this basis,we study the content of carbon nanotube influence to mechanical and electrical properties, we find composite materials can get high relative density after press; At the volume content of carbon nanotube low 11%, carbon nanotube may act as enhancements to hardness ,composite hold better electrical conductivity. After high 11%, relative density quick decrease and resistance quick increase, for carbon nanotube do not complete disperse. Because the low interface strength of carbon nanotube and metal matrix, carbon nanotube do not act as enhancements to bending.By electroless plating , we may coat a layer metal on the surface of carbon nanotube,in order to increase the interface strength of carbon nanotube and metal matrix. Because of small size, big curvature , it is very difficult to coat a layer metal on the surface of carbon nanotube. By study we find the activeness of carbon nanotube may be enhanced after oxidization, sensitization and activation. Then we consider temperature ,PH and composition of plating bath, in order to make the speed of coating as possible as slow. At last we can get a layer continuous metal Cu and Ag.we study the characterization of composite material after carbon nanotube be coated , find hardness and electrical properties more enhance and carbon nanotube can act as enhancements to bending. Then wematix at their interface and the mechanism of breakage.更多还原