Single step densification of high permittivity BaTiO3 ceramics at 300 ºC
Single step densification of high permittivity BaTiO3 ceramics at 300 ºC
复制标题
DOI：
10.1016/j.jeurceramsoc.2019.12.022
复制
发表时间：
2020-04
影响因子：
5.7
通讯作者：
K. Tsuji;A. Ndayishimiye;Sarah Lowum;Rich Floyd;Ke Wang;Maxwell T. Wetherington;J. Maria;C. Randall
中科院分区：
文献类型：
--
作者：
K. Tsuji;A. Ndayishimiye;Sarah Lowum;Rich Floyd;Ke Wang;Maxwell T. Wetherington;J. Maria;C. Randall
用熔融氢氧化物熔剂在300℃、520 Mpa、12h的单轴压力下，采用一步冷烧法制备了致密的纳米BaTiO3陶瓷。透射电子显微镜显示出致密的显微组织和尖锐的晶界。根据助熔剂的不同，平均粒径为75−150 nm。介电常数为700-1800，室温为106赫兹，介电损耗为tanδ∼0.04。用BaTiO_3的本征尺寸效应解释了介电常数和相变行为的差异。纳米晶BaTiO_3陶瓷仍表现出宏观的铁电开关，表现为滞后回线。这项工作表明，冷烧结工艺可以一步实现铁电氧化物的致密化。此外，获得了与报道的纳米晶颗粒的介电性能相当的值，但此时，使用了有史以来最低的加工温度。
Dense nanocrystalline BaTiO3ceramics are prepared in a single step by the Cold Sintering Process at 300 °C, under a uniaxial pressure of 520 MPa for 12 h using a molten hydroxide flux. Transmission electron microscopy reveals a dense microstructure with sharp grain boundaries. The average grain sizes are 75−150 nm depending on the flux amount. The dielectric permittivity is 700–1800 at room temperature at 106Hz, with a dielectric loss, tan δ ∼ 0.04. The difference in permittivity and phase transition behavior are explained in terms of the intrinsic size effect of the BaTiO3. The nanocrystalline BaTiO3ceramics still shows a macroscopic ferroelectric switchingviaa hysteresis loop. This work demonstrates that cold-sintering process could enable the densification of ferroelectric oxides in a single step. Futhermore, comparable dielectric properties to reported values for nanocrystalline grains are obtained, but at this time, with the lowest processing temperatures ever used.