Densification Behavior and Dielectric Properties of BaO-R2O3-TiO2 Microwave Ceramics

• Main Authors: Lung-Teng Cheng, 鄭隆藤
• Other Authors: Sea-Fue Wang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/93127986544488523768

碩士 === 國立臺北科技大學 === 材料及資源工程系碩士班 === 91 === The dielectric properties of BaO-R2O3-TiO2 ceramic system possesses a high dielectric constant (70 — 100), which are enable miniaturization of the dimensions of devices. In this study, the BaO-R2O3-TiO2 ceramics were prepared by a solid reaction method with lanthanide substitutions. The effects of composition modification and processing parameters on the densification behavior, microstructural evolution and microwave dielectric properties of BaO-R2O3-TiO2 ceramics were investigated. The results exhibited the Ba5.1(Sm1-yNdy)8.6Ti18O54 solid solutions with y = 0.5 have excellent dielectric properties ( εr = 91, Q x f = 907 GHz, τf = 7.3ppm/℃ ). Moreover, Ba5.1(Sm1-yLay)8.6Ti18O54 solid solutions with y = 0.25 also showed excellent dielectric properties ( εr = 90, Q x f = 1185 GHz, τf = 29.2 ppm/℃ ). However, Ba5.1(Pr1-yNdy)8.6Ti18O54 solid solutions didn’t show a near-zero temperature coefficient of resonant frequency. The results indicated only Sm based ceramics have a negative τf. As a result, Substitution of Nd, La and Pr for Sm will achieve the goal of a near-zero temperature coefficient of resonant frequency.