坚韧且高温稳定的类珍珠层Bi4Ti3O12基压电陶瓷

中文摘要 AI 辅助

基于Bi4Ti3O12的陶瓷因其高居里温度（>600°C）而成为高温压电器件的有前景候选材料。然而，其低压电常数和较差的机械可靠性阻碍了其在某些工程应用中的使用。在此，我们通过可扩展的磁辅助 slip casting（MASC）自组装工艺制备了类珍珠层<00l>织构（f_00l > 94%）的Bi3.96Ce0.04Ti2.965W0.0175Nb0.0175O12（NL-BCWNT）陶瓷。除了晶体学织构外，最终材料呈现出砖-泥微观结构，具有中位纵横比为15的微米级晶粒。NL-BCWNT表现出压电陶瓷的高断裂韧性，K_IC和K_J分别达到2.2±0.4 MPa·m^0.5和4.2±0.4 MPa·m^0.5。增韧源于类珍珠层结构内的裂纹偏转和稳定裂纹扩展。d_33为30±3 pC/N，居里温度为661°C，d_33*在160°C时达到46±3 pm/V，且残余应变小于随机BCWNT。这些改进归因于沿自发极化方向<h00>排列的畴具有更好的迁移率。NL-BCWNT表现出优异的铁电疲劳抗性，超过10^6次循环而无退化。此外，在纯BiT中也观察到类似的改进，表明该策略对其他BiT基体系具有普遍适用性。因此，类珍珠层结构为高性能机电材料的设计工具箱提供了有前景的补充。

英文摘要

Bi4Ti3O12-based ceramics are promising candidates for high-temperature piezoelectric devices owing to their high Curie temperature (> 600 °C). However, their low piezoelectric constants and poor mechanical reliability hinder their use in some engineering applications. Here, we fabricate nacre-like <00l>-textured (f_00l > 94%) Bi3.96Ce0.04Ti2.965W0.0175Nb0.0175O12 (NL-BCWNT) ceramics via a scalable magnetic-assisted slip casting (MASC) self-assembly process. In addition to crystallographic texture, the final material presents a brick-and-mortar microstructure with micro-sized grains with a median aspect ratio of 15. NL-BCWNT exhibits a high fracture toughness for piezoceramics, with both $K_{IC}$ and $K_J$ reaching 2.2 $\pm$ 0.4 $MPa \cdot m^{0.5}$ and 4.2 $\pm$ 0.4 $MPa \cdot m^{0.5}$, respectively. The toughening originates from deflection and stable crack propagation within the nacre-like structure. The $d_{33}$ is 30 $\pm$ 3 $pC/N$ with a Curie temperature of 661$°C$, and $d_{33}^*$ reaches 46 $\pm$ 3 $pm/V$ at 160 $° C$ with less remanent strain than random BCWNT. The improvements are attributed to aligned domain along spontaneous polarization direction <h00> with better mobility. NL-BCWNT exhibited excellent ferroelectricity fatigue resistance with higher than 106 cycles without degradation. Furthermore, similar improvements are observed in pure BiT, suggesting the general applicability of this strategy to other BiT-based systems. The nacre-like architecture thus provides a promising addition to the design toolbox for high-performance electromechanical materials.

发表机构

• Imperial College London（帝国理工学院）
• Technical University of Denmark（丹麦技术大学）

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