The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diff...The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.展开更多
CaO-B203-SiO2 （CBS） glass powders are prepared by conventional glass melting method at different melting temperatures whose properties and microstructures are characterized by X-ray diffraction （XRD） and scanning ...CaO-B203-SiO2 （CBS） glass powders are prepared by conventional glass melting method at different melting temperatures whose properties and microstructures are characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It is found that there are SiO2 and some unknown phases in CBS glass melting liquid from 1 300 ℃ to 1 500 ℃ and the amount of these phases decreases with the increase of the melting temperature. The CBS glass melted at 1 450 ℃ could be sintered from 830 ℃ to 930 ℃ and the bulk densities of the samples are all higher than 2.4 g/cm^3. From the points of the properties and energy conservation, the melting temperature of 1 450 ℃ is the optimal melting temperature. The glass ceramic sintered at 850 ℃ exhibits better dielectric properties： er=6.33, tan6=2.2×10^-3 at 10 GHz, and the major phases of the samples are CaSiO3, CaB2O4 and SiO2.展开更多
基金Project(2007AA03Z0455) supported by the National High-Technology Research and Development Program of ChinaProject(BE2009168) supported by the Natural Science Foundation of Jiangsu Province in ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institution,China
文摘The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.
基金Project(2007AA03Z0455) supported by the National High Technology Research and Development Program of ChinaProject(BE2010194) supported by Science&Technology Pillar Program of Jiangsu Province, China+1 种基金Project(KF201103) supported by the State Key Laboratory of New Ceramic and Fine Processing, Tsinghua University, ChinaProject supported by the Priority Academic Development of Jiangsu Higher Education Institutions, China
文摘CaO-B203-SiO2 （CBS） glass powders are prepared by conventional glass melting method at different melting temperatures whose properties and microstructures are characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It is found that there are SiO2 and some unknown phases in CBS glass melting liquid from 1 300 ℃ to 1 500 ℃ and the amount of these phases decreases with the increase of the melting temperature. The CBS glass melted at 1 450 ℃ could be sintered from 830 ℃ to 930 ℃ and the bulk densities of the samples are all higher than 2.4 g/cm^3. From the points of the properties and energy conservation, the melting temperature of 1 450 ℃ is the optimal melting temperature. The glass ceramic sintered at 850 ℃ exhibits better dielectric properties： er=6.33, tan6=2.2×10^-3 at 10 GHz, and the major phases of the samples are CaSiO3, CaB2O4 and SiO2.
