Effects of CaO-B2O3 Glass on Sintering and Microwave Properties of Cordierite Ceramics for Low-Temperature Cofired Ceramics

The densification behavior and dielectric properties of cordierite ceramics adding three different proportions of CaO-B2O3 glass were investigated. The cordierite ceramics were prepared from the waste of porous ceramics. Their crystalline phases, densification parameters, dielectric properties, and microstructure were addressed. The densities of all samples firstly increased and then decreased. The crystalline phase of samples was cordierite. It was considered that CaO-B2O3 glass and cordierite ceramic did not react in the process of sintering. With 10, 15, 20wt% CaO-B2O3 glass added, the maximal densities of samples were 2.46, 2.42, and 2.33 g/cm(3), respectively, obtained at 1060, 1000, and 940 degrees C. The materials had a low dielectric constant and a low dielectric loss [epsilon approximate to 5, tan delta (2-3) x 10(-3), at about 10 GHz]. The sample, with 15 wt % CaO-B2O3 glass added, sintered at 1020 degrees C (binder burning temperature at 500 degrees C, with a heating rate of 3 degrees C/min) had better properties (epsilon = 5.14, tan delta = 2.23 x 10(-3) at 10.328 GHz). [DOI: 10.1143/JJAP.47.3572]