| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系碩士班 === 92 === Among numerous microwave materials, Ba2Ti9O20 ceramics material has good microwave characteristics, such as high dielectric constant(εr), high quality factor(Q), and temperature coefficient of resonant frequency(τf) close to zero. It is not easy to get monophasic Ba2Ti9O20 by making use of traditional solid-state reaction. In this study, we discussed the influence of excess and deficient TiO2 on the phase stability of Ba2Ti9O20 and microwave characteristics . Morever, the sintering temperature of pure phase is above 1300℃ and it cannot match with cooper or silver electrode for co-firing. In order to lower sintering temperature, glass addition was used. Then, we discuss the sintering behavior , the variety of micro-structure in processing of sintering, and the dielectric properties.
The results show that Ba2Ti9O20 can be synthesized and stabilized by adding 4wt% ZrO2 and calcined at temperature1200℃.The Ba-B-Zn-Si-Li glass had a great influence on the densification of Ba2Ti9O20 ceramics. Sintering density 4.21 (g/cm3) at 1100℃ can be obtained. After sintering at 1000 ℃, good dielectric properties includeεr ＝32, Q×f ＝17145 and its τf ＝10.92 can be achieved.
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