Study Of Medium Temperature Sintering Of Bnt High-frequency Dielectric Ceramics

The purpose of this paper is to prepare a new microwave dielectric ceramic which has high permittivityε,low dielectric loss tanδ,and low temperature coefficient of capacitanceαC. The BNT (BaO-Nd₂O₃-TiO₂) system of dielectric ceramics is selected for the study. As the pure BNT ceramics'dielectric performance do not meet the requirements of our experiments, some doping treatment, and some process improvements are used in the experiments.Bi₂O₃, Bi₄Ti₃O₁₂, G1 glass, and GB glass as additives are used in the doping process. Through experiments can be found: when the mass ratio of Bi₂O₃ and Nd₂O₃ is 3:7, and on that basis, by adding 2wt% Bi₄Ti₃O₁₂ additives, BNT dielectric performance of ceramics can meet the test requirements. In addition, adding a low melting point glass after sintering process, the liquid formed by the glass additive will have a positive impact on ceramics. Wetting by glass, to meet the requirements of the dielectric performance of the premise, the sintering temperature can be reduced.In addition, the process on the impact of BNT ceramics is studied .After adjusting the calcining temperature, the holding time of calcining , and the sintering temperature, the optimum sintering process is gotten:The best calcining temperature:1110℃The best holding time of calcining: 1 hourOptimum sintering temperature: 1150℃(ascending 5 hour,holding 6 hour)Through the experiment, the dielectric performance of the ceramic prepared are as follows: K:ε=90±5 (measurement frequency 1MHz) Dielectric loss: tanδ<4×10-4 (measurement frequency 1MHz) Capacitance temperature coefficient:αC<30ppm/℃(-55-125℃,measurement frequency 1MHz)...