Carbon nanotubes produced by arc discharge and mechanical properties of CNTs reinforced aluminum composites

• Main Author: 張智評
• Other Authors: 陳立業
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/78099763861242834742

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 91 === In this study, the production of carbon nanotubes(CNTs) by arc-discharge has been investigated. The product is used as the reinforcement in Al matrix composites. The effects of different parameters on the yield and quality of CNTs are discussed in the thesis. Under an optimum condition, CNTs with diameters 20~50nm and about several microns in length are deposited on the anode. Graphite can be largely eliminated after liquid phase purification, leaving the CNTs as well as carbon nanoparticles. Wet mixing of the Al powder and nano-powders is adopted to avoid agglomeration of the nano-powders. After cold isostatic pressing and vacuum sintering, composites with a density close to 100% of the theoretical density after extrusion is obtained. The addition of 1 wt% unpurified CNTs lower the tensile strength of the composites. It can be attributed to two reasons. The large graphite particles become stress concentrated under tensile stress. Also, wetting of the metal and the graphite is poor, causing the graphite particles to cleave or break away from the matrix, leading to a low tensile strength. The tensile strength is largely enhanced with the addition of 1wt% purified CNTs as reinforcement, the tensile properties is even higher than those of a composite reinforced with 10 wt% micrometric SiC. In summary, our study shows that CNTs have superior strengthening effect in Al-MMC.