| Summary: | 碩士 === 崑山科技大學 === 電子工程研究所 === 99 === In this paper, phase formation, microstructure and microwave dielectric properties of doped Zn0.5Ti0.5NbO4 and ZnTiO3 ceramics by the reaction-sintering process were investigated. The main phase ZnTiNb2O8 accompanied by second phase CaNb2O6 formed in ZTN-CT (0.95Zn0.5Ti0.5NbO4-0.05CaTiO3) ceramic. The optimum density and shrinkage were 5.21 g/cm3 and 18.74%, respectively. εr＝29.2, Q×f≒ 10,770GHz, τf ≒－33.76 ppm/oC were found for 1100oC/4h sintering ZTN-CT. The main phase with a same structure of ZnTiNb2O8 formed in ZNTN ((Zn0.8Ni0.2)0.5Ti0.5NbO4) ceramic. Second phase Ni0.5Ti0.5NbO4 formed in ZNTN especially when sintering temperature increased. The optimum density and shrinkage were 5.29 g/cm3 and 17.37%, respectively. εr＝38.58, Q×f≒16,544GHz, τf≒－4.52 ppm/oC were obtained for 1150oC/2h sintering ZNTN. The main phaseα-Zn2TiO4 accompanied by TiO2 (rutile) formed in ZT (ZnTiO3) ceramic. The optimum density and shrinkage were 4.96 g/cm3 and 16.04%, respectively. εr＝29.38, Q×f≒20,113GHz, τf ≒＋31.42 ppm/oC were obtained for 1250oC/6h sintering ZT. The main phase similar to α-Zn2TiO4 accompanied by TiO2 (rutile) formed in ZMT (Zn0.93Mg0.07TiO3) ceramic. The optimum density and shrinkage were 4.91 g/cm3 and 15.99%, respectively. εr＝28.92, Q×f≒20,314GHz, τf ≒＋35.22 ppm/oC were obtained for 1150oC/6h sintering ZMT.
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