Li0.5Bi0.5MoO4对Li2Zn2(MoO4)3陶瓷的微波介电性能影响

采用传统固相反应法制备了xLi_0.5Bi_0.5MoO₄-(1-x)Li₂Zn₂(MoO₄)₃ xLBM-(1-x)LZM]复合陶瓷,研究添加不同质量分数(x=25%,30%,35%,40%和45%)的LBM对LZM陶瓷的烧结特性、物相组成、微观结构以及微波介电性能的影响。结果表明:添加一定量的LBM不仅能将LZM的谐振频率温度系数(τ_f)调节近零,还能降低LZM的烧结致密化温度;LBM可与LZM共存,且不发生化学反应生成其他新相。随着LBM添加量增加,复合陶瓷的烧结致密化温度逐渐降低、体积密度先增大后减小、介电常数(ε_r)与τ_f逐渐增大而品质因数(Q×f)逐渐减小。当LBM添加量为40%时,LZM-LBM复合陶瓷在600 ℃烧结2 h获得最大体积密度为4.41 g/cm³,以及优异的微波介电性能:ε_r为13.8,Q×f为28 581 GHz,τ_f为-4×10^-6/℃。

Effect of Li0.5Bi0.5MoO4 on Microwave Dielectric Properties of Li2Zn2(MoO4)3 Ceramics

The xLi_0.5Bi_0.5MoO₄-(1-x)Li₂Zn₂(MoO₄)₃ xLBM-(1-x)LZM] composite ceramics were prepared by traditional solid-state reaction method. The sintering characteristics, phase composition, microstructures and microwave dielectric properties of LZM ceramics with different mass fraction (x=25%, 30%, 35%, 40% and 45%) of LBM were investigated. The results show that, LBM effectively adjust the resonant frequency temperature coefficient (τ_f) of LZM ceramics to near zero and also decreases the sintering temperature; LBM can coexist with LZM, and no new phases are detected in addition to the LZMT and LBM phase. With the increase of LBM ceramics, the sintering densification temperature decreases gradually, the bulk density of composite ceramics initially increases and then decreases, the permittivity (ε_r) and τ_f increases, the quality factor (Q×f) decreases gradually. When 40%LBM ceramics is added, LZM-LBM composite ceramics sintered at 600 ℃ for 2 h obtained maximun bulk density of 4.41 g/cm³,and excellent microwave dielectric properties of the ε_r is 13.8, the Q×f is 28 581 GHz and τ_f is -5×10^-6/℃.