核-殼 奈米複合材料之合成及其微波吸收效應研究

synthesis and microwave absorption properties of core-shell structural nanocomposite materials

甘世維(Shih-Wei Kan)

指導教授 ： 王宏文

中原大學/理學院/化學研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400299

摘要

本研究主要是以Ni-Zn 鐵氧磁粉材料為主，以水熱法製備奈米級Ni-Zn鐵氧磁粉並嘗試改變水熱反應條件(如:濃度) ,或以熱處理的方式變化粒子的大小。也藉由摻雜微量的金屬離子和添加不同比例金屬銀粒,來觀察吸波材料的遲滯效應。
運用不同粒徑、不同摻雜和添加不同比例金屬銀粒，觀察對電磁波吸收的影響；發現利用熱處理方式產生的奈米磁粉具有往高頻遷移的遲滯效應,而不同摻雜微量金屬離子則是產生往低頻遷移的遲滯效應,添加不同比例金屬銀粒則產生依比例往高頻遷移的趨勢,並且
伴隨著 double layer(同時具有吸收層與反射層) 效應。

關鍵字

電磁波吸收 ； 奈米複合材料 ； 核殼結構

並列摘要

Nanosized powders of Ni0.5Zn0.5 Fe2O4 with well-developed spinel phases were prepared by the hydrothermal method. An average particle size about 10 ~ 20 nm of Ni-Zn ferrite powder is obtained. Heat treatment and the concentration of reagent are two factors to get large particles.The magnetic hysteresis behavior of the absorber are affect by the cationic dopants and the core-shell structure which Ag is used as the core.

The electromagnetic properties of permittivity and permeability are measured in 2-15GHz frequency range.There are different observations of hysteresis effect by varing particle sizes and doping different cationic dopants and doping different ratio of Ag . The sharp decrease of real part of permeability (μ?) shifts to higher frequencies while the sharp peak of imaginary part of the permeability (μ?) also shifts to correspond high frequencies by heat treatment .There is an evidence that the sharp peak of real part (μ?) and imaginary part (μ?) of the permeability are shifted to lower frequencies by different cationic dopants . The sharp peak of real part (μ?) and imaginary part (μ?) of the permeability are shifted to higher frequencies with the increase of Ag. According to Debye-Hertz potential equation, microwave absorption data(reflection loss) are calculated with the four parameters(ε?、ε?、μ?、μ?) ,frequency and thickness of layer.

並列關鍵字

core-shell structure ； microwave absorption ； nanocomposite materials

參考文獻

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