Effects of chemical composition variation and Bi-B-Zn-Si glass addition on sintering behavior, magnetic and dielectric properties of Co2Z hexaferrite

• Main Authors: Li-PaoJheng, 鄭利保
• Other Authors: Hsing-I Hsiang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/00459324391721245301

碩士 === 國立成功大學 === 資源工程學系碩博士班 === 98 === The trends for electric devices were light and slim, most inductors were produced in multilayer form. In multilayer process, ferrite will co-fire with the inner electrode - silver. So the sintering temperature must be lower than the melting point of silver. Most low temperature co-fire ferrite investigations have focus on Ni-Cu-Zn ferrite, but the initial permeability of Ni-Cu-Zn ferrite will decrease dramatically while the frequency is higher than 100MHz due to Snoek's limit. So in higher frequency applications, Ni-Cu-Zn ferrite was substituted by hexa-ferrites. Microwave inductor, hexa-ferrite Co2Z must sinter above 1200℃, it is unfavorable for multilayer process, because the sintering temperature is higher than the melting point of silver. So we should lower the sintering temperature of Co2Z. In this study, we envisage improving magnetic properties by varying chemical composition, and decrease the sintering temperature below 900℃ by adding BB35SZ glass. The experiment results exhibit: (1) At lower sintering temperature, added excess soluble ions in Co2Z will cause second phase formation. (2) When more BB35SZ glass was added, Co2Z will decompose to M phase and other second phases such as U phase or S phase. (3) Samples have compositions 3(Ba0.9Bi0.1O)．2(Co0.8Cu0.2O)．12(Fe1.957Zn0.025O3) and added 2wt% BB35SZ glass sinter at 900℃ for 2 hours can get better magnetic properties. (μ’=3.4, Q=11)