Synergistically enhancing the piezoelectric activity and Curietemperature of CaBi_(4)Ti_(4)O_(15) ceramics via co-doping Gd/Mn at theA/B-site  

作　　者：Yu Chen Zhi Zhou Lingfeng Li Daowen Wu Qingyuan Wang 

机构地区：[1]School of Mechanical Engineering,Chengdu University,Chengdu 610106,China

出　　处：《Journal of Advanced Ceramics》2024年第9期1482-1497,共16页先进陶瓷（英文）

基　　金：funded by the National Natural Science Foundation of China(No.12372179);supported by the State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics(No.MCMS-E-0522G01).

摘　　要：As a typical Aurivillius-type compound, CaBi_(4)Ti_(4)O_(15) (CBT) is considered a strong competitor among hightemperature piezoelectric materials, but it is difficult to achieve both high piezoelectric activity and a high Curie temperaturefor CBT. In this work, the method of double-ion co-substituting at different crystalline sites was used to modify the electricalproperties of CBT. The Gd/Mn co-doped CBT ceramics with the chemical formula of Ca_(1−x)Gd_(x)Bi_(4)Ti_(4)O_(15)+0.2 wt% MnO_(2)(CBT–100xGM, x = 0–0.11) were prepared via the conventional sintering process. The phase and valence band structures,chemical compositions and microstructures, dielectric and ferroelectric properties, electrical conduction behaviors, andelectroelastic and piezoelectric properties of the ceramics were characterized. The doping concentration effects of Gd^(3+)were analyzed according to the composition-dependent structures and properties of CBT–100xGM. The donor substitutionof Gd^(3+) for Ca^(2+) at the A-site reduced the tolerance factor of the perovskite-like structure and decreased the concentration ofintrinsic oxygen vacancies. While Mn^(3+) tended to substitute for Ti4+ at the B-site, the extrinsic oxygen vacancies are limitednear the defect center of Ti(Mn) because of the formation of ( ‒MnTi')• as defect dipoles. The thermal depoling behavior ofthe CBT–100xGM ceramics between 300 and 700 ℃ was explained by the thermodynamic characteristics of the defectdipoles. The optimized composition with x = 0.08 (CBT–8GM) had a high TC ≈ 809 ℃ and a high piezoelectric coefficient(d33) ≈ 23 pC/N, as well as a piezoelectric voltage constant (g33) value of up to 21.5×10^(−3)(V·m)/N. Moreover, it can maintaina residual d33 ≈ 80% after being annealed at 700 ℃. This good anti-thermal depoling ability endows this material with greatapplication potential in high-temperature piezoelectric devices with operating temperatures exceeding 500 ℃. Thesynergistic enhancement in the piezoelectric activity and Curie tem

关 键 词：Aurivillius-type compounds CaBi_(4)Ti_(4)O_(15) double-ion substitution oxygen vacancy radial vibration mode electrical conduction behavior 

分 类 号：TN312.8[电子电信—物理电子学] TQ174.758.23[化学工程—陶瓷工业]