Abstract

(Bi_0.5Na_0.5)TiO₃ (BNT) lead-free ceramics were prepared by the seed-induced technique using different particle sizes of BaTiO₃ (BT) powder as seeds. The BT seeds was synthesized by the molten-salt method and then calcined at different temperatures of 750 (750BTs), 800 (800BTs) and 850 °C (850BTs). The pure perovskite seeds (5 mol%) were mixed with the starting materials of the BNT system for conventional mixed oxide method. After that, the mixture was calcined and sintered at 900 °C for 2 h and 1100 °C for 2 h, respectively. From results it was found that the particle size of BT seed increased with calcine temperature increase from 750 to 850 C. The samples of non-BT seed (S0) and BT seed-added (S1, S2 and S3) showed pure perovskite phase. Average density values were in the range of 5.53-5.77 g/cm³. Dielectric constant (ε_r) measured at room temperature (at 1 kHz) was in the range of 732.04-788.59. The dielectric loss (tanδ), remnant polarization (P_r) and coercive field (E_c) values decreased with the addition of BT seed. The highest piezoelectric coefficient (d₃₃) ∼156 pC/N was obtained for the sample of 850BTs (S3).

摘要

采用不同粒径的BaTiO _3，通过种子诱导技术制备了（Bi _0.5 Na _0.5）TiO ₃（BNT）无铅陶瓷。（BT）粉末作为种子。BT种子通过熔融盐法合成，然后在750（750BTs），800（800BTs）和850°C（850BTs）的不同温度下煅烧。将纯钙钛矿种子（5摩尔％）与BNT系统的原料进行常规混合氧化物法混合。之后，将混合物分别煅烧并在900°C下烧结2 h和1100°C下烧结2 h。从结果发现，随着煅烧温度从750℃增加到850℃，BT种子的粒度增加。非BT种子（S0）和添加了BT种子的样品（S1，S2和S3）显示出纯钙钛矿相。平均密度值在5.53-5.77g / cm ³的范围内。介电常数（_εr在室温（在1kHz）下测得的）在732.04-788.59的范围内。随着BT种子的加入，介电损耗（tanδ），残余极化（P _r）和矫顽场（E _c）值降低。850BTs（S3）样品的最高压电系数（d ₃₃）〜156 pC / N。