Low temperature sintering and dielectric properties of (Zr_(0.8)Sn_(0.2))TiO_4 microwave ceramics using La_2O_3/BaO additives

摘要

The effects of La_2O_3/BaO additives on the sintering behavior and dielectric properties of (Zr_(0.8)Sn_(0.2))TiO_4 (ZST) microwave ceramics were investigated. With La_2O_3/BaO additives, the sintering temperatures can be effectively lowered. The dielectric properties of ZST ceramics were strongly dependent on the amount of La_2O_3/BaO additives. As the amount of La_2O_3/BaO additives increased from 0.5 to 2.0 wt.%, the dielectric constants ε_r increased following the trend with density and the τ_f values of dense sintered ZST ceramics increased from +1.3 to +18.3 ppm℃~(-1) steadily. The quality values Q first increased, reached a maximum at 1.0 wt.% La_2O_3/BaO, and then decreased with the further increase of La_2O_3/BaO amount for all sintering temperatures. The 1.0 wt.% La_2O_3/BaO-doped ZST ceramics sintered at 1350℃ for 4 h had the optimum dielectric properties: ε_r = 38; τ_f = +5.6ppm℃~(-1); Q = 11575 (1.8GHz). At the level of 0.5-2.0 wt.% additives, no second phase was observed by the X-ray diffraction (XRD) analysis.