以奈米壓痕法量測填鐵奈米碳管叢之機械性質

Abstract

奈米碳管是近幾年來引起話題的新興材料，尤其是鍵結上的特殊結構與極小的尺寸都使奈米碳管在電磁與機械性質更引人注目。填鐵奈米碳管叢是在成長碳管同時填入鐵奈米線於碳管中空處，由於過度元素(鐵、鈷、鎳)具軟磁性，因而更加彰顯材料之磁性能；然而，卻鮮少文獻針對填鐵奈米碳管叢之機械性質做研究，本研究中以化學氣相沉積法製備填鐵奈米碳管叢，並利用奈米壓痕技術量測填鐵碳管叢之機械性質，探討填鐵率與機械性質之間的關係。 首先，探討填鐵奈米碳管叢之成長溫度對碳管叢高度的影響，以及外加碳源對碳管叢高度的影響。固定填鐵來源 二茂鐵的用量，改變碳管成長速率就能改變填鐵的比例。在穿透式顯微鏡下觀測填鐵率後，以奈米壓痕測試不同填鐵率之填鐵碳管叢的機械性質。 實驗結果發現以成長溫度增加與外加碳源濃度提高都能增加碳管高度，外加碳源可突破單用二茂鐵成長填鐵碳管叢之高度限制；另一方面，奈米壓痕試驗的結果顯示，填鐵碳管叢之機械性質與填鐵率相關且呈現指數增加的關係，當填鐵率由增加至48.1%，彈性模數由4.9增為71.8 MPa、硬度由0.534增加為2.044 MPa。

Carbon nanotubes arouse a lot of interests in the field of technology. Based on the atomic structure and its tiny size, amazing electromagnetic and mechanical properties have been predicted and proved. The magnetic behavior is enhanced by means of filling iron nanowire into the hollow center of nanotube, which is as grown iron-filled carbon nanotube turfs. Besides, mechanical property of iron filled carbon nano turfs is barely discussed in related research. In this study, we aims to synthesis iron-filled carbon nanotube turfs by chemical vapor deposition and then measure the mechanical property by nanoindentation. And also, relation between mechanical property and iron filling ratio is discussed in this research. The growth parameters, temperature of growth and concentration of additional carbon source, are controlled first to investigate the relation to height of iron filled carbon nanotube turfs. With the changes on height of carbon nanotube turfs, the iron filling ratio are also altered. The iron filling ratio and diameters of carbon nanotube is observed by transmission electron microscope and then mechanical property of each sample is measured by nanoindentation. The results showed increasing growth temperature and concentration of additional carbon source would raise up the height of iron filled carbon nanotube turfs. When providing additional carbon source, the height limit of iron filled carbon nanotube turfs could be break through. On the other hand, the results of nanoindentation exhibit dependent relation of between mechanical property and iron filling ratio. The mechanical property would have exponential growth by increasing iron filling ratio.