透過您的圖書館登入
IP:34.238.138.162
  • 學位論文

銀在鐵氧磁體與低溫共燒陶瓷系統中之擴散行為探討

Diffusion behavior of Silver in Ferrite and LTCC Co-firing system

指導教授 : 段維新

摘要


本研究主要探討銀電極在低溫共燒陶瓷與鎳銅鋅-鐵氧磁體共燒系統中的擴散行為,並分成兩大部分:第一部分探討填充劑粒徑對低溫共燒陶瓷性質所產生的影響。第一部份係將不同粒徑的氧化鋁填充劑粉末與玻璃粉末混合,並於不同溫度燒結後,進行各項分析。第二部分則探討低溫共燒陶瓷(二氧化矽-氧化鋁-氧化鉀玻璃陶瓷粉末, 簡稱SAK-LTCC)、鎳銅鋅-鐵氧磁體與銀電極共燒時之反應與銀的擴散行為。第二部分第一階段先將三者粉末混合製備成塊材試樣,探討不同材料共燒後之反應與變化;第二階段則將三者以厚膜疊層方式製備成多層試樣,於高溫燒結後,分析不同排列方式對其微結構、物質交換及擴散行為之影響。 第一部分實驗結果顯示:在900˚C共燒後,兩個第二相─鋅鋁尖晶石及鈣長石生成。不同的氧化鋁填充劑粒徑,對鋅鋁尖晶石的粒徑大小有顯著影響;鈣長石在溫度提升到950˚C後生成量明顯增加,對於系統結晶度與介電性質有相當助益。低溫共燒陶瓷(SAK-LTCC)、鎳銅鋅-鐵氧磁體與銀共燒後,鐵氧磁鐵粉末粒徑過細、低溫共燒陶瓷黏度較高、及過程中產生的方石英相,皆對緻密度有不良影響;低溫共燒陶瓷本身具優良介電性質,但其品質因數(Q-factor)在混入銀及鎳銅鋅-鐵氧磁體後大幅下降。 多層試樣中,銀電極在不同排列方式中的擴散係數相近,約為10-11cm2/sec;銀電極的擴散同時受到微量氯離子、富氧化銅液相以及玻璃基地的催化,於共燒後電極厚度顯著增加、相鄰材料的組成大幅改變。另外,鎳銅鋅-鐵氧磁體與低溫共燒陶瓷間,因銀電極促進其擴散產生方石英相,造成介面上孔洞生成;兩者間不同的緻密化速率與收縮率亦可能造成多層試樣的層裂,上述幾點皆影響了元件的完整性。另一方面,氧化鋁與二氧化矽結晶相,對於銀擴散具有阻擋作用,是故調整各層組成、結合適當的層厚與排列組合方式,應對於維持元件完整性,有正面助益。

並列摘要


The present study is divided into two parts. In the first part, alumina filler with three different sizes was co-fired with an Al2O3-SiO2-B2O3 glass at 800-950˚C. In the second part, SAK-LTCC (SiO2-Al2O3-K2O glass+ceramics) layer, NiCuZn-ferrite layer and Ag electrode, were laminated to form various patterns. For the first part, after co-firing the alumina fillers with glass powder at 900 and 950˚C, two second phases, gahnite (ZnAl2O4) and anorthite (CaAl2Si2O8) were formed. The size of gahnite particles depends strongly of the size on the alumina filler; significant increase of anorthite from 900 to 950 ˚C is a major factor for increased crystallinity. Anorthite formation, higher crystallinity and grain growth all result in higher Q-factor after sintering at 950˚C. However, poor densification behavior was observed after co-firing the SAK-LTCC, NiCuZn-ferrite and Ag together. The fine grain-size of ferrite, high-viscosity of LTCC and the cristobalite formation are the reasons for low density. The SAK-LTCC exhibit good dielectric properties, but after the addition of ferrite and Ag powders, the Q-factor decreases significantly. For laminated specimens, the diffusivity of Ag in ferrite or LTCC, is about 10-11cm2/sec. It is closed with each other within various patterns. The diffusion of silver was promoted by the additives, Cu-rich liquid phase and the amorphous glass matrix. In addition, the inter-diffusion between NiCuZn-ferrite and LTCC was promoted due to the insert of Ag electrode. Cristobalite and pores are formed at the interface. Owing to densification and shrinkage mismatches, thickness of Ag electrode is increased; the delamination at interface was also observed. On the other hand, Al2O3 and SiO2 crystals can inhibit the diffusion of silver. To adjust the composition and appropriate thickness of each material and laminated with a symmetric pattern may substantially improve the compatibility of multilayer components.

參考文獻


1. Y. Wang, H. Zhang, L. Li, Y. He, W. Ling,” Effect of CaO–B2O3–SiO2 glass on the magnetic and dielectric properties of NiCuZn ferrites”, J. Magn. Magn. Mater., 324[4], 471-474 (2011)
2. C.J Dileep, T. K. Sowmya, E. K Sunny, N. Raghu, N. Venkataramani and A. R. Kuikarni,” Influence of Nature of Filler on Densification of Anorthite-Based Crystallizable Glass+Ceramic System for Low Temperature Cofired Ceramics Application”, J. Am. Ceram. Soc., 92[3], 595-600 (2009)
3. M. T. Sebastian and H. Jantunen ,” Low loss dielectric materials for LTCC applications: a review”, Int. Mater. Rev., 2 [2], 57-90 (2008)
4. S. Rajesh, H. Jantunen, M. Letz and S. Pichler-Willhelm,” Low Temperature Sintering and Dielectric Properties of Alumina-Filled Glass Composites for LTCC Applications”, Int. J. Appl. Ceram. Technol., 9[1], 52-59 (2012)
5. J. Kim, S. Hwang and W. Sung and H. Kim,” Effect of anorthite and diopside on dielectric properties of Al2O3/glass composite based on high strength of LTCC substrate”, J Mater. Sci., 43[12], 4009–4015 (2008)

延伸閱讀