【作者】 易国军；

【导师】 蒋文忠； 陈小华；

【作者基本信息】 湖南大学 ， 材料物理与化学， 2004， 硕士

【摘要】 碳纳米管具有极高的强度、韧性、弹性模量及其纳米尺寸和极大的长径比,使其有望成为复合材料理想的增强体。同时,其优良的电导率、热导率、化学稳定性和热稳定性,也可能使复合材料多功能化。 本文首先对碳纳米管的制备、表面改性和镍的包覆进行了研究。采用溶胶—凝胶的方法制备了镍催化剂,在此基础上用化学气相沉积的方法高产率地制备了碳纳米管。通过硝酸和盐酸的纯化,得到了纯度较高的碳纳米管,并使碳纳米管表面产生大量的官能团;然后在Sn和Pd溶液中进行敏化活化处理,使碳纳米管表面形成密集的活化点;再用化学镀的方法对碳纳米管进行了镍的包覆,可得到连续、均匀的镀层。热处理后镀层更光滑、致密。另外,本文还对敏化活化及镍包覆碳纳米管的相关机理进行阐述。为进一步制备新型纳米级复合材料打下坚实的实验和理论基础。 其次,研究了用热压成型和冷压成型两种工艺方法制备碳纳米管铜基复合材料的工艺参数,对复合材料的力学性能、电学性能进行了测试;并对复合材料的磨损和碳纳米管对铜基体的增强机理进行了探讨。测试结果与分析表明:少量碳纳米管在铜基复合材料中的分布比较均匀,碳纳米管少量的加入能显著地提高铜基复合材料耐磨性能、硬度和抗拉强度;虽然碳纳米管的加入会引起铜基复合材料电阻率的升高,但电阻率的大小仍然和纯铜是处在同一个数量级上。 最后,本文对碳纳米管铜基复合材料的热学性能进行了研究,并探讨了碳纳米管对复合材料热学性能影响的机理。研究结果表明:碳纳米管铜基复合材料的热膨胀系数随温度的升高而增大,其值大大低于纯铜的热膨胀系数,且在高温下的稳定性很好;尽管碳纳米管的加入引起了复合材料热导率的下降,但在电子封装材料领域的应用中还是具有一定的理论和实验参考价值。此外,利用复合材料热膨胀系数的微观力学模型对碳纳米管铜基复合材料的热膨胀系数进行了理论模拟计算,理论值比实验值有所偏高,并对偏高的可能原因进行了探讨。更多还原

【Abstract】 Carbon nanotubes (CNTs) have many attractive properties such as the high yang’s module, high flexibility, and high aspect ratios, which make them ideal candidates for the reinforcing filler of the composite materials. In addition, the excellent electric conductivity, thermal conductivity, the chemical stability and thermal stability of CNTs are benefit to make the multi-functional composite materials.In present study, we first investigated the synthesis, surface modification and the Ni-coating of the CNTs. CNTs were synthesized in large scale using the Ni catalysts prepared via sol-gel method. The CNTs then were purified by nitric acid and hydrochloric acid. After purified, many functional groups were created on the surface of the clear CNTs. Then, the CNTs were put into Sn and Pd solutions for sensitizing and activating treatment. Therefore, dense activated positions were created on the surface of the CNTs. Subsequently, the homogeneous and continuous Ni layer on the surface of the CNTs were prepared using the electroless plating method. After the thermal treatment, more smooth and dense coating layer can be obtained. In addition, the mechanism of the synthesis, activation, sensitization and the Ni-coating CNTs are discussed. The synthesis of the CNTs and the Ni- coating CNTs provide the experimental and the theoretical understanding for further synthesis of the nivel composited materials in nano-scale.Secondly, we prepared the copper-based CNTs (Cu/ CNTs) composite materials using the hot-pressing and the cold-pressing method. The processing parameters were optimized during the prepared process. The mechanical and electrical properties of the Cu/ CNTs composite were measured. The abrasive mechanism of the composite and the reinforcing mechanism of the CNTs filler in the Cu matrix are also discussed. Experimental results indicate that small quantities of CNTs can be distributed homogenously in the Cu matrix, The wear resistance, hardness and the tensile strength of the Cu/ CNTs composite can be obviously improved due to the filling of the CNTs. The electrical resistivity of Cu/ CNTs composite increased with the addition of in the更多还原