高頻用鎳錳鐵氧磁體的開發研究

Development of Ni-Mn ferrite for high frequency application

利嘉翔(Chia-hsiang Li)

指導教授 ： 魏萬益

大同大學/工程學院/材料工程學系所/碩士(2004年)

摘要

在高頻下，鎳錳鐵氧磁體有不錯的磁特性表現，添加過量氧化鐵時，於氧分壓較高之環境下，基地中將殘留反鐵磁性之氧化鐵二次相，阻擋磁矩移動，因此能夠提升共振頻率。添加鈷離子時，由於能夠提升鐵氧磁體之異方性使磁壁穩定化而提升共振頻率。有系統性的分析化學組成、燒結氣氛及燒結溫度對於磁特性的關聯性，量測項目主要包括:微觀組織、μ’-f curve、μ”-f curve及X-ray結構分析。由實驗結果顯示，μ’會隨錳離子比例增加而增加，而共振頻率沒有太大的變化，當降低燒結溫度、鈷離子比例增加、產生析出物時，可提升共振頻率，但μ’會隨之遞減。由此可知析出物及添加鈷離子對於高頻磁特性的影響，可配合材料的使用頻率調整成分比例、燒結條件以達期望之性質。

關鍵字

二次相 ； 初導磁率 ； 高頻 ； 鐵氧磁體

並列摘要

In this study, Ni-Mn ferrites with different content of manganese, cobalt, and iron ions were prepared through conventional ceramic processing method. The specimens were sintered under various sintering conditions and atmosphere. The results showed that the μ’ and μ”max were increased slowly with the increase of the manganese ion content but the fm were decreased slowly with the increase of the manganese ion content. The μ’ and μ”max were decreased and the resonance frequencies were increased with the increase of the cobalt or iron ion content. Incorporation of the cobalt ions into the ferrites can enhance the resonance frequency by changing its anisotropy. In other words, the contribution of cobalt ions was increasing the domain-wall stabilization. The effects of excessive iron ions were present when the granular α-Fe2O3 second phase particles were formed in the matrix to hinder the domain wall motion. Grain growth, occurred at high temperature, and formation of the second phase, occurred at low temperature, are in competition. The grain growth could be inhibited by the presence of the second phase. Thus, second phase and doping the cobalt ions are effective ways in the manufacturing of ferrite materials for high frequency applications.

並列關鍵字

ferrite ； permeability ； second phase

參考文獻

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