Bi_2MoO_6对Bi_2Mo_2O_9低温烧结陶瓷微波介电性能的影响

Effect of Bi_2MoO_6 on microwave dielectric properties of Bi_2Mo_2O_9 ceramics with low sintering temperature

采用氧化物固相反应法制备xBi_2MoO_6+(1–x)Bi_2Mo_2O_9(x为摩尔分数,x=0.20,0.25,0.30,0.35,0.40)系列微波介质陶瓷,研究Bi2MoO6不同掺入量对陶瓷晶相结构、显微形貌及介电性能的影响.结果表明:烧结后xBi_2MoO_6+(1–x)Bi_2Mo_2O_9陶瓷晶相为Bi2MoO6正交和Bi_2Mo_2O_9单斜两相混合,Bi2MoO6加入量对晶体结构和晶粒尺寸有明显影响;Bi2MoO6掺入量对陶瓷的微波介电性能影响显著,随着x增大,xBi_2MoO_6+(1–x)Bi_2Mo_2O_9陶瓷的相对介电常数(!r)、品质因素(Qf)和谐振频率温度系数(τf或TCF)减小.在650℃空气下烧结2h、谐振频率7.70GHz条件下,0.35Bi2MoO6+0.65Bi_2Mo_2O_9陶瓷的!r=29.9,Qf=10450GHz,"f=1.2#10–6/℃,具有优良的微波介电性能,有望应用于低温共烧陶瓷工艺中.

In the present study, the microwave dielectric properties and microstructures of the xBi2 MoO6 ＋ （1 -x ） Bi2 Mo2 O9 （x= 0. 20, 0. 25,0. 30, 0. 35 and 0. 40, x is molar fraction） ceramics have been investigated as a function of the amount of Bi2 MOO6. The results show that the sintered bodies are a diphase mixture of Bi2 MoO6 orthogonal structure and Bi2 Mo2 O9 monclinic structure. The relative dielectric constant （6）, quality factor （Q f） and temperature coefficient of resonant frequency （ τ f） of xBi2 MoO6 ＋（1 -x ） Bi2 Mo2 O9 ceramics decrease gradually with the increasing of x. The ceramic sample of x= 0. 35 sintered at 650 ℃ for 2 h demonstrated the best microwave dielectric property with a relative dielectric constant of about 29. 9. a high quality factor （Qf） of about 10450 GHz at 7.70 GHz and a near zero τf about ＋1.2 × 10 -6/ ℃. Considering the low sintering temperature,0.35Bi2Mo3 O12 ＋0.65Bi2Mo2O9 could be a candidate for microwave application and low temperature co fired ceramics （LTCC） technology.