鐵氧磁體,介電材料與銀在低溫共燒陶瓷系統中之燒結行為探討

Sintering Behavior of Ferrite, Dielectric and Ag in Low Temperature Co-firing systems

王真(Zhen Wang)

指導教授 ： 段維新

國立臺灣大學/工學院/材料科學與工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.02734

摘要

本研究主要探討了銀電極在鐵氧磁體-介電材料低溫共燒系統中的擴散行為， 分為兩大部份：第一部份是將鐵氧磁體和介電材料的粉末混合，於不同溫度燒結后，製成複合材料，並探討其介電和磁性性質。第二部份則探討鐵氧磁體層，介電材料層與銀電極共燒時之反應與銀的擴散行為。將三者以疊層方式製備成多層試樣，於高溫燒結後，分析不同層狀結構對其微結構，物質交換及擴散行為之影響。
第一部份實驗結果顯示：除了含90% ferrite試樣，鐵氧磁體-介電材料複合材料可以在950℃以下燒結緻密.介電材料對鐵氧磁體的晶粒大小有很大的抑制作用。複合材料的介電性質會被添加的鐵氧磁體抑制，磁性也會被添加的介電材料抑制。用Maxwell-Garnett 理論預測複合材料的磁性變化，結果與測量值吻合，且較偏向於以介電材料為基底的理論預測。
多層試樣中，由於鐵氧磁體和介電材料的熱收縮係數不匹配，造成嚴重的分層現象。銀電極的擴散受到高溫，液相以及高濃度銀的催化，於共燒後電極厚度顯著增加。另外，銀電極兩側的鐵氧體和介電材料相互之間也有擴散，並在銀/介電材料之間形成新的反應層。

關鍵字

低溫共燒 ； 介電材料 ； 鐵氧體 ； 銀擴散 ； 電磁性質

並列摘要

The present study aims to investigate the co-firing behavior between dielectric and ferrite. The present study is divided into two parts. In the first part, a series of powder mixtures composing of low-temperature-fired dielectric and NiZn ferrite have been prepared. The reactions between the dielectric and ferrite during co-firing are investigated. In the second part, dielectric layer, ferrite layer and Ag electrode, were laminated together to form various patterns. The diffusion behavior between the dielectric and ferrite is studied.
For the first part, the composites can be densified below 950℃except the specimen containing 90% ferrite. The addition of dielectric inhibits the grain growth of ferrite. The resonance frequency increases with the increase of ferrite content; while the dielectric constant decreases at the same time. A larger permeability μ’ is observed with increasing NiZn ferrite content. The Maxwell-Garnett mixing rule was used to describe the magnetism of the composites, assuming dielectric or NiZn ferrite as matrices. The measured results were closer to the values calculated by using dielectric as matrix.
For laminated specimens, two groups of specimens were prepared. The delamination was observed in some laminates. It may due to the difference in the sintering shrinkage and thermal expansion. The diffusion distance increases with the increase of co-firing temperature. The diffusion behavior is also affected by the design of Ag pattern. The inter-diffusion between ferrite and dielectric is taken place during co-firing. The Fe, Cu, Ni, Zn (from ferrite) diffuse to dielectric layer and the Ti and Nd (from dielectric) diffuse to ferrite layer. A new layer is formed between Ag layer and dielectric layer as the laminate was fired at 950℃.

並列關鍵字

low-temperature-cofiring ； dielectric ； ferrite ； silver diffusion ； inter-diffusion ； electromagnetic properties

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