Effect of BaO, SrO and MgO addition on microwave dielectric properties of (Zr_(0.8),Sn_(0.2))TiO_4 ceramics

摘要

The effect of BaO, SrO or MgO on (Zr_(0.8),Sn_(0.2))TiO_4 (ZST) ceramics has been investigated. It is found that the ZST ceramics densifled at lower sintering temperatures of 1300°C, 1350°C and 1400°C for the samples added with BaO, SrO and MgO, respectively. The reduction in sintering temperature with the addition of BaO can be attributed to the liquid phase effect. The addition of BaO and SrO additives significantly improved the density, microstructure and the microwave dielectric properties of the ZST ceramics com?pared to MgO. No secondary phases were observed with the addition of BaO, SrO or MgO up to 1.5 wt% of the additives. The dielectric constant (epsilon_r) and the temperature coefficient of the resonant frequency (tau_f) of the ZST ceramics with these additives are not affected much where as the quality factors (Q X f_0) are affected. The maximum Q X f_0 of the ZST ceramics obtained are 60,300, 54,250 and 38,850 for the samples added with BaO, SrO and MgO, respectively. The increase in Q X f_0 is attributed to the uniform grain growth, increase in grain size and density. The effect of these additives on structure, microstructure densification and microwave dielectric properties are discussed.