材料期刊网

为了进一步探索合成工艺对钛酸铋钠系无铅材料的结构及介电特性的影响,本文以甘氨酸为燃料,利用固相-燃烧法制备了CeO2掺杂的Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 (BNKT)陶瓷.XRD表明,在固相合成工艺中引入燃烧法制备BNKT陶瓷,比传统固相法降低预烧温度150 ℃,掺杂的CeO2扩散进入了BNKT钙钛矿的晶格,且当掺杂量为0%~0.3%时,形成纯的钙钛矿相结构;SEM表明,CeO2掺杂使晶粒尺寸趋于平均,对晶粒生长有抑制作用;介电温谱表明,随着CeO2掺杂量增加,介电常数εr和退极化温度Td、相转变温度Tm降低,介电反常峰逐渐弱化,且室温至300 ℃,介电损耗tanδ始终在0.3%以下,并从微结构缺陷空位形成机制角度,结合铁电畴壁运动状态,分析讨论了对材料介电特性的作用规律.

In order to further explore the effect of synthesis process on structure and dielectric properties of the sodium bismuth titanate lead-free materials, thus, taking glycine as fuel, cerium-doped Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 (BNKT) ceramics were prepared by the solid-combustion composite method.X-ray diffraction (XRD) data shows that the calcined temperature, combining the combustion method in solid phase synthesis process, declined by 150 ℃ than that of conventional solid state method and CeO2 diffused into the lattice of BNKT ceramics, as well as the pure perovskite phase was formed while the amount of CeO2 was 0%-0.3%.SEM images indicate that the doping of CeO2 made grain crystal size uniform and restrained crystal grain growth.The temperature dependence of the dielectric constant and dissipation factor shows that the dielectric constant εr, depolarization temperature Td and the inversion temperature Tm of the antiferroelectric to ferroelectric phase decreased with addition of CeO2, and also the dielectric peak was weakened gradually and the dielectric loss tanδ is below 0.3% between room temperature and 300 ℃.Furthermore, combining microstructural vacancy mechanism with ferroelectric domain wall movement, the law of function is discussed and analyzed.