火焰燃燒法備製奈米錳鋅/鎳鋅鐵氧體及電磁特性討論

Electromagnetic Properties of Nanosized MnZn/NiZn Ferrites Synthesized by Combustion Method

魏輔均(Fu-Jun Wei)

指導教授 ： 周傳心

共同指導教授 ： 傅昭銘(Chao-Ming Fu)

國立臺灣大學/工學院/應用力學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.10399

摘要

鐵氧體材料具有特殊的介電與磁特性且被廣範應用於日常生活，例如高功率電源轉換器、磁讀寫及電磁吸收體等。鐵氧體材料的製程方式包含了固態法、共沉法、溶膠-凝膠法、水熱法，以及近幾年由Patil等人所發表之火燄燃燒法。根據文獻，火燄燃燒法所備製的鐵氧體材料仍須經由長時間的高溫熱處理以去除反應不完全的雜相。而高溫熱處理過程所需的能量及時間，相對地提高了材料備製的成本。因此，若能夠省去高溫熱處理的步驟，必將提高材料製程的效率並且降低製程成本。
本實驗透過改變火燄燃燒法的製程參數，備製鐵氧體材料。將未經高溫熱處理的樣品，經由X光粉末繞射儀及掃描式電子顯微鏡觀察其結晶特性，並利用振盪樣品磁度儀及阻抗分析儀量測樣品的磁電特性。經由實驗結果得知，透過特定的製程參數，可在不經高溫熱處理的前提下，備製高純相的鐵氧體材料，且其磁特性亦明顯提升。
透過本實驗所改進的火燄燃燒法，可備製高純相及良好磁特性的鐵氧體材料，且因不須經由高溫熱處理，大幅提升了材料製程效率。關於材料特性的量測及分析，將在本論文中進一步討論。

關鍵字

燃燒合成法 ； 火燄燃燒法 ； 鎳鋅鐵氧體 ； 錳鋅鐵氧體 ； 尖晶石結構

並列摘要

Polycrystalline ferrites, due to their versatile magnetic and electrical behaviors, have many applications, such as high frequency transformer and recording heads etc. There are many synthesis methods of ferrite material, including conventional solid solution method, coprecipitation, sol-gel, hydrothermal, citrate precursor, etc. In recent years, there has been tremendous interest in utilizing the combustion synthesis for ultra-fine powders of polycrystalline ferrites. In the most of reported combustion methods for ferrites, post annealing processes are required to improve the phase purity and magnetic properties of ferrites. It is of interest to improve synthesis condition of combustion in order to prevent the post annealing process, for not only the energy saving but efficiency of process.
In this thesis, novel synthesis conditions to improve the combustion synthesis for ferrites have been investigated. In the course of this study, ferrites were synthesized utilizing combustion reaction with various processing parameters. The synthesized ferrites were characterized by X-ray diffraction and scanning electronic microscopy. Magnetic properties were measured using vibrating sample magnetometer and magneto-impedance properties were measured using impedance analyzer. The results have demonstrated the ferrites synthesized by combustion method without post annealing process are highly purity phase, with an average grain size about 20 ~ 70 (nm) estimated using Scherrer’s formula, the saturated magnetization are in the range of 5 ~ 62 (emu/g) and coercivity varies about 10 ~ 200 (Oe).
The synthesized ferrites with highly purity phase can be applicable for high frequency electromagnetic devices. Details will be discussed in the thesis.

並列關鍵字

combustion synthesis ； NiZn ferrite ； MnZn ferrite ； spinel structure

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