Low Temperature Sintering and Microwave Dielectric Properties of Ba₄Nd_9.33Ti₁₈O₅₄ Ceramics Doped with Crystallizable Glass

The effect of CaO-B₂O₃-SiO₂ glass on the densification, microstructure and microwave dielectric properties of Ba₄Nd_9.33Ti₁₈O₅₄ ceramics was investigated in this work. It was found that the addition of a few amount of glass (≤2%) could effectively decrease the sintering temperature owing to the viscous sintering. However, locally porous structures were formed when overmuch glass was added because of enwrapped air bubbles and rapid grain growth. In addition, the amount of remaining glass after sintering could be decreased due to the re-crystallization of CaO-B₂O₃-SiO₂ glass. Sol-gel derived Ba₄Nd_9.33Ti₁₈O₅₄ ceramics containing 2 wt% glass can be well densified at 950ºC and exhibit good microwave dielectric properties of ε_r=68 and Q×f=7400 GHz.