Aurivillius phase CaBi₂Nb₂O₉ (CBNO) ceramic with an ultrahigh Curie temperature (T_c) of ∼934 °C shows huge potential in high-temperature piezoelectric applications. However, low piezoelectricity and poor electric insulation prevent its applications in high-temperature sensing. Here, we propose an effective multi-field coupling strategy to synergistically optimize piezoelectric property, electrical conduction behavior and temperature stability of CBNO ceramic. The constructed lattice stress and electric fields induced by introducing Li/Pr and Bi/Sc doping have great impacts on the lattice structure, microstructure, domain structure and defect chemistry. Therefore, a significant increase in piezoelectric activity (d₃₃) is resulted from the enhancement of polarization, the improvement of breakdown electric field and the production of nanoscale domains. In especial, the existence of pseudo-tetragonal phase boundary is helpful for the enhanced d₃₃. In the designed Ca_1–3x(Li_0.5Pr_0.5)_xBi_2+2xNb_2–xSc_xO₉ system, a high d₃₃ of ∼18.2 pC/N accompanied by an ultrahigh T_c of ∼938 °C is achieved in the x=0.02 ceramic. This combined with high electrical resistivity (ρ∼1.72 MΩ cm at 600 °C) and nearly stable d₃₃ (up to 800 °C) indicates that it is a very promising piezoelectric material for high-temperature (up to 600 °C or higher) sensing applications.

中文翻译：

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通过多场耦合策略在基于 CaBi2Nb2O9 的高温压电陶瓷中实现出色的高压电综合性能


Aurivillius 相 CaBi₂Nb₂O₉ （CBNO） 陶瓷具有 ∼934 °C 的超高居里温度 （TC_），在高温压电应用中显示出巨大的潜力。然而，低压电性和较差的电绝缘性阻碍了其在高温传感中的应用。在这里，我们提出了一种有效的多场耦合策略，以协同优化 CBNO 陶瓷的压电性能、导电行为和温度稳定性。引入 Li/Pr 和 Bi/Sc 掺杂所诱导的晶格应力和电场对晶格结构、微观结构、畴结构和缺陷化学有很大影响。因此，压电活性 （d₃₃） 的显着增加是由于极化的增强、击穿电场的改善和纳米级畴的产生。特别是，伪四方相界的存在有助于增强 d₃₃。在设计的 Ca_1-3x（Li_0.5Pr_0.5）_xBi_2+2xNb _2-xSc_xO₉ 系统中，在 x=0.02 陶瓷中实现了 ∼18.2 pC/N 的高 d₃₃ 和 ∼938 °C 的超高 T_c。这与高电阻率（600 °C 时 ρ∼1.72 MΩ cm）和几乎稳定的 d₃₃（高达 800 °C）相结合，表明它是一种非常有前途的压电材料，适用于高温（高达 600 °C 或更高）传感应用。