Spark plasma sintering of high-TC calcium bismuth niobate (CaBi2Nb2O9) with superior piezoelectric performance

• Published in: Journal of the European Ceramic Society 2025-04, Vol.45 (4), p.117065, Article 117065
• Main Authors: Chen, Juan-Nan, Pei, Xuan-Zhe, Wang, Qian, Zhao, Xian, Wang, Ze-Yan, Wang, Chun-Ming
• Format: Article
• Language: English
• Subjects: Bismuth layer-structured ferroelectrics (BLSFs); Calcium bismuth niobate (CaBi2Nb2O9); Grain orientation; High-temperature piezoelectric ceramics; Lotgering factor; Spark plasma sintering (SPS); Textured ceramics; Thulium oxide (Tm2O3)
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2024.117065

Calcium bismuth niobate (CaBi2Nb2O9) is a promising ceramic material for high-temperature piezoelectric applications due to its high Curie temperature (TC) of 940 °C. However, its practical use is limited by poor piezoelectric performance and low direct-current (DC) electrical resistivity at elevated temperatures. In this study, we introduced pseudo-tetragonal distortion into CaBi2Nb2O9 by substituting rare-earth thulium ions, which reduced domain wall energy, facilitated domain switching, and decreased the presence of oxygen vacancies. These enhancements significantly improved both the piezoelectric performance and DC electrical resistivity of the material. To further enhance piezoelectric performance, we prepared textured thulium-substituted CaBi2Nb2O9 ceramics with a Lotgering factor (f) of up to 77.4 % using a two-step spark plasma sintering method. The resulting textured CaBi2Nb2O9 ceramics exhibited superior piezoelectric performance, with a piezoelectric constant d33 of 25.2 pC/N, four times higher than that of non-textured CaBi2Nb2O9. Importantly, these textured ceramics maintained excellent electrical properties at elevated temperatures, suggesting their suitability for high-temperature piezoelectric device applications.