Microwave dielectric properties of (1 − x)Mg(Sn0.05Ti0.95)O3–x(Ca0.8Sr0.2)TiO3–y wt% ZnNb2O6 ceramics with near-zero temperature coefficient
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The microstructures and the microwave dielectric properties of (1 − x)Mg(Sn0.05Ti0.95)O3–x(Ca0.8Sr0.2)TiO3−y wt% ZnNb2O6 (x = 0.05–0.08, y = 2–8) ceramics system prepared by conventional solid-state route were investigated. The crystalline phases and the microstructures of the ceramics were characterized by means of X-ray diffraction and scanning electron microscopy. Zn2+ partially replaced Mg2+ in Mg(Sn0.05Ti0.95)O3 and formed the ilmenite-type (Mg1−δZnδ)(Sn0.05Ti0.95)O3 phase. Second phase (Mg1−δZnδ)(Sn0.05Ti0.95)2O5 increased remarkably when excess ZnNb2O6 added. ZnNb2O6 as additives could not only effectively lower the sintering temperature of the ceramics to 1320 °C, but also promote the densification. The microwave dielectric properties of specimens were strongly related to ZnNb2O6 and (Ca0.8Sr0.2)TiO3 content. The optimized microwave dielectric properties with ε r ~ 22.13, Q × f value ~60,613(at 7 GHz) and τ f value ~0.4 ppm/ °C were achieved for (1 − x)Mg(Sn0.05Ti0.95)O3–x(Ca0.8Sr0.2)TiO3–y wt% ZnNb2O6 (x = 0.07, y = 4) sintered at 1320 °C for 2 h.
KeywordsResonant Frequency Sinter Temperature Unit Cell Volume Apparent Density High Dielectric Constant
This work was supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT), IRT1146.
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