English  |  正體中文  |  简体中文  |  Items with full text/Total items : 65275/65275 (100%)
Visitors : 20912110      Online Users : 223
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version


    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/65096


    Title: 鈷金屬與鈷金屬氧化物奈米結構製備及其性質研究
    Authors: 邊夢涵;Bian,Meng-han
    Contributors: 化學工程與材料工程學系
    Keywords: 鈷金屬;鈷金屬氧化物;陽極氧化鋁模板
    Date: 2014-08-28
    Issue Date: 2014-10-15 14:40:14 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 本研究利用陽極氧化鋁奈米模板結合電化學沉積法,成功地製備出長度可調控的一維鈷金屬奈米線與奈米管,並由實驗結果觀察,奈米管管壁厚度有一梯度變化。經由場發射性質量測可得知鈷金屬奈米線與奈米管,其啟動電場分別為1.75V/μm與2.43V/μm。除此之外,我們發現鈷金屬奈米線的場增強因子(β)的數值比鈷金屬奈米管大,推測造成此現象的原因為遮蔽效應的影響。
    本研究將鈷金屬奈米線分別在350℃與450℃的氧氣氛圍下進行不同熱氧化時間的處理,會因為Kirkendall effect效應製備Co3O4之串珠狀奈米管,並且利用TEM對鈷金屬氧化過程中的形貌、晶體結構與生成機制進行有系統性的研究,可知Co金屬會先轉變為CoO最終氧化成Co3O4,再利用HE-TEM觀察到CoO生成與靠近Co之處,而Co3O4位在CoO之外層。
    本研究利用熱氧化法製備大面積Co3O4,並推測其成長機制為尖端生長,在氧化過程中釋放氧化層內部的應力,自然形成氧化鈷奈米線。接著以水滴接觸角量測其表面親疏水性質,並發現可以藉由真空退火、置於真空環境下以及置於一般大氣環境下,讓其表面轉變為疏水性質,並推測其機制與表面氧原子之脫附有關。
    ;In this study, we have demonstrated that length-tunable copper nanowires and nanotubes were successfully produced by using the anodic aluminum oxide (AAO) nanotemplate combined with the electrodeposition process. As the result, the wall thickness of nano tube with a gradient variations. Field emission measurements showed daturn-on fields of Co nanowire and nanotube are 1.75 V/μm and 2.43 V/μm, respectively. Moreover, the field enhancement factor(β) of Co nanowires was found to be larger than that of Co nanotubes, the result might be attributed to the so-called screen effect.
    In this study, the cobalt nanowires were treated with different thermal oxidation time under oxygen atmosphere at 450℃ and 350℃.Finally, it became bead-like nanotube with kirkendall effect. We study the morphology、crystal structure and formation mechanism of Co wire during thermal oxidation with TEM. In this observation, we can tell that the sequence of the appeared cobalt oxide phase is from CoO to Co3O4, and the CoO generated at the close to the Co , and the site of Co3O4 is outside the CoO.
    In this work , we fabricated the large-area Co3O4 nanowire by air oxidation of Co film .The possible mechanisms of the growth of nanowires are discussed in the context of the stress relaxation from the oxidation layer. In addition, the surface-wetting properties of the Co3O4 nanowires were evaluated by water contact angle measurements. We found that the wetting behaviors changed from hydrophilic to hydrophobic by vacuum annealing 、 placed under a vacuum environment or atmospheric environment. We speculate that this phenomenon is related to the desorption of surface oxygen atoms.
    Appears in Collections:[化學工程與材料工程研究所] 博碩士論文

    Files in This Item:

    File Description SizeFormat
    index.html0KbHTML652View/Open


    All items in NCUIR are protected by copyright, with all rights reserved.

    社群 sharing

    ::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期:8-24-2009 :::
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - Feedback  - 隱私權政策聲明