Sintering behavior and characteristics study of BaTiO₃ with 50 wt% of B₂O₃-Bi₂O₃-SiO₂-ZnO glass

Abstract The thermal analysis of B₂O₃-Bi₂O₃-SiO₂-ZnO (BBSZ) glass with different particle sizes and LiF addition was researched to study its temperature behavior. Next the composites with 50 wt% BaTiO₃–50 wt% BBSZ glass were prepared for shrinkage, microstructures and dielectric properties investigations. The differently treated BBSZ glass showed that the smaller glass particles clearly decreased its softening and crystallization temperatures. LiF addition had the same but much weaker effect. The composites showed two-stage shrinkage related to the softening of the glass and new phase generation of Bi₂₄Si₂O₄₀ at 385–450 °C, and Bi₄BaTi₄O₁₅ over 680 °C. The microstructures of the composites sintered at 720 °C showed Bi₄BaTi₄O₁₅, BaTiO₃ and Bi₂₄Si₂O₄₀ with residual ZnO phase. LiF addition increased the amount of Bi₄BaTi₄O₁₅, thus increasing the loss value. However the particle size of the glass did not effect to the dielectric properties of the composites showing permittivity of 248–256 and loss of 0.013 at 100 kHz

Low dielectric loss ceramics in the Mg₄Nb₂O₉-ZnAl₂O₄-TiO₂ ternary system

Abstract This study used a traditional solid-state reaction method to prepare a series of composite ceramics in the 0.7Mg₄Nb₂O₉-(0.3-x)ZnAl₂O₄-xTiO₂ ternary system. Crystalline phases and microstructure of Mg₄Nb₂O₉-ZnAl₂O₄-TiO₂ dielectric ceramic composites were investigated and correlated with the relevant dielectric properties. It was observed that the addition of Ti⁴⁺ substituted Nb⁵⁺ in the Mg₄Nb₂O₉ structure, which promoted the decomposition of Mg₄Nb₂O₉ to form the second phase, Mg₅Nb₄O₁₅, during sintering. The synergistic effect of ZnAl₂O₄-TiO₂ co-doping promoted the Mg₄Nb₂O₉ ceramic densification. The sample (0.7Mg₄Nb₂O₉-(0.3-x)ZnAl₂O₄-xTiO₂) with x = 0.15−0.2 exhibited dielectric constants of 13–14, larger than those of ZnAl₂O₄, Mg₄Nb₂O₉ and Mg₅Nb₄O₁₅, due to the NbO₆ octahedra distortion resulting from the substitution of Al³⁺/Ti⁴⁺ for Nb⁵⁺ in Mg₄Nb₂O₉ and Mg₅Nb₄O₁₅. The long-range order of the NbO₆ octahedra was enhanced by co-doping ZnAl₂O₄ and TiO₂, thereby enhancing the Qxf value. A dielectric constant of 13.1, Qxf value of 366,000 GHz and a τf of −60.8 ppm/°C were obtained from 1300 °C sintered 0.7Mg₄Nb₂O₉-0.15ZnAl₂O₄-0.15TiO₂. These results show that 0.7Mg₄Nb₂O₉-0.15 ZnAl₂O₄-0.15TiO₂ ceramic is a good candidate for microwave electronic device applications

Tape casting system for ULTCCs to fabricate multilayer and multimaterial 3D electronic packages with embedded electrodes

Abstract A 3D multilayer structure built by two ultra‐low temperature co‐fired ceramic (ULTCC) compositions with silver embedded electrodes are co‐fired at a temperature of 450°C. The 3D multilayer module is prepared by laminating the ULTCC green tapes with a new binder system, which organics can be completely burned out at temperature of 250°C before the sintering of the ULTCC 3D modulus. High‐density microstructures are achieved for the sintered module. In this study, the ULTCC feasible binder system is introduced. Also, ULTCC multilayers and multimaterial structures with surface and embedded silver electrodes are fabricated. This research opens up a new horizon for fabrication of electroceramic devices with embedded electrodes in multimaterial devices