【摘要】： 碳包覆金屬納米顆粒是一種新型的納米碳／金屬復(fù)合材料,它呈現(xiàn)膠囊狀的碳?xì)ぐ步饘偌{米顆粒的殼／核結(jié)構(gòu),包覆殼層為無定形碳結(jié)構(gòu)或多層石墨層結(jié)構(gòu),內(nèi)核為金屬納米顆粒。這種獨(dú)特的結(jié)構(gòu)不僅可以防止金屬納米顆粒氧化和環(huán)境降解,而且能夠有效抑制金屬納米顆粒的團(tuán)聚,解決了金屬納米顆粒在空氣中不能穩(wěn)定存放的問題。碳包覆金屬納米顆粒具有一些獨(dú)特的電學(xué)、光學(xué)、磁學(xué)性等能,在磁記錄材料、鐵磁流體、磁共振成像、催化劑、新能源和生物醫(yī)學(xué)等許多領(lǐng)域有著廣泛的應(yīng)用前景,成為材料科學(xué)研究的熱門課題。 本文首先綜述了碳包覆金屬納米顆粒的制備方法及其應(yīng)用。并對(duì)直流電弧等離子體制備金屬納米粉體技術(shù)進(jìn)行了探討,等離子體具有熱效率高、溫度高、能量集中、電弧穩(wěn)定、氣氛可控和便于急冷等特點(diǎn),為納米材料的形成與生長提供了理想的物理化學(xué)環(huán)境。我們采用已有的直流電弧等離子體實(shí)驗(yàn)裝置成功制備出鐵納米粉體,并采用X射線衍射儀、透射電子顯微鏡、選區(qū)電子衍射、比表面積和孔隙分析儀、振動(dòng)試樣磁強(qiáng)計(jì)等多種手段對(duì)納米鐵粉體的晶體結(jié)構(gòu)、形貌、粒度及其分布和磁性等進(jìn)行了表征。 本文同時(shí)對(duì)現(xiàn)有的直流電弧等離子體實(shí)驗(yàn)裝置進(jìn)行改進(jìn),成功的制備出碳包覆鐵納米顆粒,采用X射線衍射儀、高分辨透射電子顯微鏡、拉曼光譜等對(duì)試樣的形態(tài)和形貌、粒度及其分布、碳?xì)さ氖潭取⒕w結(jié)構(gòu)等特征進(jìn)行表征。采用振動(dòng)試樣磁強(qiáng)計(jì)、X射線能量色散分析譜儀、熱重-差熱分析儀等對(duì)制備的碳包覆鐵納米顆粒的化學(xué)成分、磁性和抗氧化性能進(jìn)行研究,研究矯頑力和飽和磁化強(qiáng)度隨粒度的變化關(guān)系。研究結(jié)果表明平均粒度為27nm的碳包覆鐵納米顆粒具有超順磁性。碳包覆鐵納米顆粒比表面經(jīng)過鈍化處理后的鐵納米粉體有更好的抗氧化性能。 最后研究了工藝參數(shù)對(duì)生成的碳包覆鐵納米顆粒形貌的影響規(guī)律,建立了直流電弧等離子體法制備碳包覆鐵納米顆粒的形成機(jī)理模型,并用熱力學(xué)、動(dòng)力學(xué)和鐵碳相圖分析了碳包覆鐵納米顆粒的形成機(jī)理。
[Abstract]:Carbon-coated metal nanoparticles are a new type of nano-carbon / metal composite material, which presents the shell / core structure of encapsulated carbon shell coated with metal nanoparticles, and the coating shell is amorphous carbon structure or multi-layer graphite structure. The core is metal nanoparticles. This unique structure can not only prevent the oxidation of metal nanoparticles and environmental degradation, but also effectively inhibit the agglomeration of metal nanoparticles, and solve the problem that metal nanoparticles can not be stored stably in the air. Carbon coated metal nanoparticles have some unique electrical, optical and magnetic properties, and have a wide range of applications in many fields, such as magnetic recording materials, ferrofluids, magnetic resonance imaging, catalysts, new energy sources and biomedicine. It has become a hot topic in material science research. In this paper, the preparation and application of carbon coated metal nanoparticles are reviewed. The preparation technology of metal nanocrystalline powder by DC arc plasma is discussed. The plasma has the characteristics of high thermal efficiency, high temperature, concentrated energy, stable arc, controllable atmosphere and convenient for rapid cooling. It provides an ideal physical and chemical environment for the formation and growth of nanomaterials. We successfully prepared the iron nanoparticles by using the existing DC arc plasma experimental device, and used X-ray diffractometer, transmission electron microscope, selected area electron diffraction, specific surface area and pore analyzer. The crystal structure, morphology, particle size and distribution and magnetic properties of nano-iron powders were characterized by vibrating sample magnetometer. At the same time, the existing DC arc plasma experimental device was improved to successfully prepare carbon coated iron nanoparticles. The morphology and morphology of the samples were investigated by X-ray diffractometer, high resolution transmission electron microscope, Raman spectroscopy, etc. The particle size and its distribution, graphitization degree of carbon shell and crystal structure were characterized. The chemical composition, magnetic properties and oxidation resistance of carbon coated iron nanoparticles were studied by means of vibrating sample magnetometer, X-ray energy dispersive spectrometer and thermogravimetric differential thermal analyzer. The relationship between coercivity and saturation magnetization with particle size was studied. The results show that the carbon coated iron nanoparticles with average particle size of 27nm have superparamagnetic properties. Carbon coated iron nanoparticles have better oxidation resistance than surface passivated iron nanoparticles. Finally, the influence of process parameters on the morphology of carbon coated iron nanoparticles was studied. The formation mechanism model of carbon coated iron nanoparticles by DC arc plasma method was established and thermodynamics was used. The formation mechanism of carbon coated iron nanoparticles was analyzed by kinetics and phase diagram.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2010
【分類號(hào)】：TB383.1

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 韋行;;天津大學(xué)成功研發(fā)出純金屬納米顆粒材料[J];上海金屬;2008年04期

2 杜松濤,熊貴光;復(fù)合金屬納米顆粒多孔硅的光學(xué)非線性特性[J];武漢大學(xué)學(xué)報(bào)(理學(xué)版);2003年05期

3 何武強(qiáng),何寶林,陳益賢,廖小娟,劉漢范;溶劑穩(wěn)定的鈀金屬納米顆粒的制備[J];中南民族大學(xué)學(xué)報(bào)(自然科學(xué)版);2004年04期

4 杜天倫;楊修春;黃文e，

本文編號(hào)：2307604