以實驗方法量測填鐵奈米碳管叢之機械性質

Abstract

填鐵奈米碳管叢由於製備方式簡便，又因為其中填有鐵奈米線，有優異的電磁性能，近年來是備受矚目的材料。然而目前針對填鐵奈米碳管叢的研究之中，主要著重於填鐵奈米碳管叢的電磁性質，關於其機械性質的文獻較為少見。本研究以化學氣相沉積法製備填鐵奈米碳管叢，並利用奈米壓痕法與實驗法量測填鐵奈米碳管叢的機械性質，討論其分層結構以及受熱情形對機械性質的影響。 實驗結果發現，推入二茂鐵催化劑的數量不但可以控制填鐵奈米碳管叢的層數及厚度，層數越多的碳管叢有越好的機械性質。五層填鐵奈米碳管叢的彈性模數是單層填鐵奈米叢的5.5倍，表面硬度更是單層填鐵奈米碳管叢的28.5倍。另外，比較單層填鐵奈米碳管叢受高溫處理後對其機械性質的影響，其中於空氣中加熱單層填鐵奈米碳管叢至200°C，表層硬度會提升到原來的2.5倍，而於氬氣中加熱，其機械性質較無明顯變化。

Measurement of the compressive elastic modulus of iron-filled carbon nanotube (CNT) forests is evaluated with two different methods. The first method uses a nanoindentation system to indent iron-filled CNT forests grown on rigid silicon substrates. Reduced modulus and hardness of iron-filled CNT forests can be measured by nanoindentation. The second experimental method uses a force gauge, a 2-axial micro-stage, and SEM to observe the behavior of iron-filled CNT forests under uniform compressive loading. Additionally, the stress vs. strain data of iron-filled CNT forests can be calculated. Both methods were performed for iron-filled CNTs with 1, 3, and 5 layers, which were synthesized by controlling adding how many pinches of ferrocene. Using nanoindentation measure system, the hardness of 5-layer iron-filled CNT surface is 8.154 MPa, which is 28.5 times of single-layer iron-filled CNTs. Also, Young’s modulus of single-layer iron-filled CNTs measured by the second method were only 73 KPa, but Young’s modulus of 5-layer iron-filled CNTs is 404.41 KPa. Interestingly, the more layers of iron-filled CNTs, the higher hardness and Young’s modulus were found. Besides, using both two experimental methods to measure the mechanical properties of single-layer iron-filled CNT forests treated with a high temperature treatment, no significant distinction can be found between the pre-treatment sample and the sample after high temperature treatment.