低頻變動磁場下填鐵奈米碳管叢之電磁特性

近年來由於奈米碳管的優異電磁特性與機械性質，受到各領域廣泛地研究及應用，自從可以將金屬奈米粒子填入奈米碳管內技術發表後，越來越多團隊研究其機制以及特性研究，發現瑱鐵奈米碳管可以大幅提升其電磁特性。目前本實驗室可以利用化學氣相沉積法合成出垂直的奈米碳管叢，其垂直的特性更加適合在電磁的領域發揮，以二茂鐵作為鐵源及碳源，成功合成出填鐵奈米碳管，其高度可達數釐米，利用試驗室所成長出的碳管從試片進行關於電磁感應與電生磁的研究，希望未來可以實際應用在實務上。文獻所指出電流在奈米碳管中是以螺旋線方式行走，如同線圈般，根據法拉第定律，可利用此特性做電磁感應，通以時變磁場觀察在不同條件參數下，奈米碳管叢感應生電的情況，探討的面相有，奈米碳管叢高度與感應電流關係、重量負載下、試片退火、填鐵與未填鐵感應電流差距、串聯與並聯以及利用與磁場源距離關係推測其單根奈米碳管叢間互感特性，最後是奈米碳管叢電生磁。實驗結果顯示，奈米碳管叢高度與感應電流成正比，推測原因為長度越長線圈所繞的圈數也越多，填鐵的情況比未填鐵時電流可以倍增2~3倍之多，原因為其內部所填的鐵如同線圈中鐵心的效果，可以大幅增強其磁場進而提高感應電流量，利用與磁場源距離實驗發現當試片距離磁場源越遠時，碳管叢比市售電感感應電流遞減的情況較緩慢，距離一公分碳管叢減少不到10％，市售電感在距離一公分處感應電流已遞減60~80％，電生磁部分，藉由較大片的碳管叢排除電線的磁場影響，通以3安培電流，在試片中心可以量測出0.21 mT 的磁場。

關鍵字

填鐵奈米碳管叢；電磁特性；螺旋電流路徑；二茂鐵

並列摘要

Becauce Carbon nanotubes with excellent magnetic and mechanical properties, it gives rise to widely study and applications in recent years. After published some papers about Fe-CNTs, more teams start to study the principle and the properties. Found that the Fe-CNT can enhance the magnetic property wildly. In our lab, we can grow the vertical aligned Fe-CNT carpet by CVD. Because of the vertical structure, it is easier to use in magnetism. Using ferrocene for carbon and iron source to grow Fe-CNT carpet, we can make the height of few centimeters easily. Using these Fe-CNT carpets to do some studies like magnetism generates electricity and electricity generates magnetism. Expect to use in pratical application. Papers pointed out that the current path in CNT is like coil. According Faraday's law, we can do electromagnetic induction test by using CNT carpets. Observe the induced current by applying time-varying magnetic field in different parameters. Like the height of CNT, under loading, annealing the CNT samples, different between Fe-CNT and CNT, series and parallel, and speculate the mutual inductance of each CNT by the result of the test the gap between sample and electromagnet. Finally, CNT carpet generates magnetism. According to the results, induced current is proportion to the height of CNT. the N The circle number of coil is proportional to the height of CNT too. The induced current of Fe-CNT carpet is 2-3 times to the CNT carpet. Because of the iron particle inside the Fe-CNT is like the iron core of the coil. The core-like iron particle enhances the magnetic field, and increases the induced current. By the result of the gap between sample and electromagnet test, we can find that the induced current of CNT carpet decays much slower than inductance. At the gap of 1 cm, the induced current decays 10% by CNT and 60-80% by inductance. About electricity generates magnetism test. By using lager CNT carpet sample, we can measure 0.21 mT at the middle of CNT carpet sample by applying current of 3 A.

並列關鍵字

Fe-CNT ； electromagnetic properties ； helical current path ； ferrocene

參考文獻

[2] S. Iijima, “Helical microtubules of graphitic carbon,” Nature, Vol. 354, pp. 56-58, 1991

[3] S. Iijima, and T. Ichihashi, “Single-shell carbon nanotubes of 1-nm diameter,” Nature, Vol. 363, pp. 603-605, 1993

[4] D. S. Bethune, C. H. Kiang, M. S. deVries, G. Gorman, R. Savoy, J. Vazquez, and R. Beyers, “Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls,” Nature, Vol. 363, pp. 605-607, 1993

[6] V. P. Veedu, A. Y. Cao, X. S. Li, K. G. Ma, C. Soldano, S. Kar, P. M. Ajayan, and M. N. Ghasemi-Nejhad, “Multifunctional composites using reinforced laminae with carbon-nanotube forests,” Nature Materials, Vol. 5, Issue 6, pp. 457-462, 2006

[7] Song I.K., Cho Y.S., Choi G.S., Park J.B., Kim D.J., “ The growth mode change in carbon nanotube synthesis in plasma-enhanced chemical vapor deposition,” Diamond Relate Material, Vol. 13 (4-8), pp. 1210–3, 2004

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低頻變動磁場下填鐵奈米碳管叢之電磁特性

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