Study on Zn-Nb Series Low Sintering Temperature Microwave Dielectric Material for Applications in Wireless Communication
Date Issued
2004
Date
2004
Author(s)
Wu, Ming-Chung
DOI
zh-TW
Abstract
Recently, wireless communication systems are growing rapidly to satisfy the personal communication requirements. Compact, small size, low cost, and multi-function are the major developing trends among these modern wireless communication devices. The objective of this thesis is to develop low sintering temperature microwave material which can be cofired with silver electrode.
This thesis consists of three parts. In the first part of the thesis, we investigated systematically the physical properties and microwave dielectric properties in respect to high quality factor value material, Zn3Nb2O8 with sintering aids. For examples of 3.0wt% BaCO3-CuO (BC) mixture added Zn3Nb2O8 and 3.0wt% MoO3-CuO mixture (MC) added Zn3Nb2O8 can be densified at 950℃ with good microwave dielectric properties. The interfacial behavior between Zn3Nb2O8 and silver electrode was investigated. The XRD studies showed no new crystalline phase was found after co-firing pure or doped Zn3Nb2O8 with silver. No migration of silver towards pure Zn3Nb2O8 was observed using electron probe X-Ray microanalyzer (EPMA). However, a slight migration of silver towards MC-added Zn3Nb2O8 was identified. The mechanism of the silver migration was believed to be resulted from the reaction between silver and MoO3.
In the second part of the thesis, we studied systematically the physical properties and microwave dielectric properties of high dielectric constant material, Bi1.5Zn0.92Nb1.5O6.92 (BZN). For example of 3wt% BC-added BZN and 3wt% MC-added BZN at 950℃ can be sintered with higher than 95% densitivity. The optimal amount of dopants is 3wt% of BaCO3-CuO or MoO3-CuO to achieve the best microwave dielectric properties. The dopant concentration was either lower or higher than 3.0wt% would detract the dielectric properties of BZN. The interfacial behavior between BZN series ceramics and silver electrode was investigated. The XRD result showed no new crystalline phase was found after co-firing BZN or doped BZN with silver. The migration of silver towards BZN-based ceramics was observed by EPMA. The mechanism of the silver migration was believed to be resulted from the interaction between silver and sintering aids or BZN material.
In the last part of the thesis, we have studied the dielectric behaviors of Bi1.5Zn0.92Nb1.5O6.92 in detail using impedance analyzer, network analyzer, and Fourier transformed infrared spectrometer. Bi1.5Zn0.92Nb1.5O6.92 exhibited low temperature dielectric relaxation behavior which caused the material to have low quality factor property.
The low sintering temperature 3.0wt% BC-added Zn3Nb2O8 ceramics has a potential for microwave filter applications.
Subjects
Bi1.5Zn0.92Nb1.5O6.92
微波介電性質
低溫燒結
共燒
銀擴散
Zn3Nb2O8
silver migration
microwave dielectric property
low sintering temperature
co-fired
SDGs
Type
thesis
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