The Phase Compositions and Microwave Dielectric Properties of Li_2Zn(Ti_(1-x)Sn_x)_3O_8 Ceramics

摘要

The Li_2Zn(Ti_(1-x)Sn_x)_3O_8 (0.02≤x≤0.20) ceramics were prepared by the conventional solid-state ceramic route. The sintering behavior, phase compositions, microstructures and microwave dielectric properties of Li_2Zn(Ti_(1-x)Sn_x)_3O_8 ceramics were thoroughly investigated. The XRD patterns of Li_2Zn(Ti_(1-x)Sn_x)_3O_8 ceramics exhibited a single spinel as the main phase in the x value range of 0.02-0.08. The dielectric constants decreased linearly with increasing the substitution of Sn, which was mainly controlled by dielectric polarizabilities and secondary phase. The variation of Q×f values was dependent on average grain sizes and secondary phase. The τ_f values of Li_2Zn(Ti_(1-x)Sn_x)_3O_8 ceramics became more negative with higher substitution of Sn, which was related to the variations of their cell volumes. Typically, the Li_2Zn(Ti_(0.92)Sn_(0.08))_3O_8 ceramic sintered at 1075°C for 4h exhibited good microwave dielectric properties: ε_r= 24.4, Q×f = 89300 GHz, τ_f= -16.0 ppm/°C.