Microstructure and electrical properties of (1-x)(K0.5Na0.5)NbO3-xBiFeO3piezoelectric ceramics

✍ Scribed by Li, Xiang ;Wu, Lang ;Xiao, Dingquan ;Zhu, Jianguo ;Yu, Ping ;Jiang, Yihang ;Wu, Jiagang

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 508 KB
• Volume: 205
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200824013

✦ Synopsis

Abstract

Lead–free ceramics (1–x)(K~0.5~Na~0.5~)NbO~3~–x BiFeO~3~ doped with 1 mol% Fe~2~O~3~ (KNNBF/x) have been synthesized by pressureless sintering. With the Fe~2~O~3~ doping, the KNNBF/x ceramics can be well sintered at 1085–1100 °C and exhibit a pure perovskite structure with x < 0.013. It was found that the crystal structure of the KNNBF/x ceramics changed from orthorhombic to tetragonal and then to pseudocubic phase with the increase of BiFeO~3~ content. The composition KNNBF/0.013 near the tetragonal symmetry that separates the orthorhombic and pseudocubic phases exhibits improved electrical properties: d~33~ = 173 pC/N, k~p~ = 0.40, ε~r~ = 905, tan δ = 4%, P~r~ = 26 μC/cm^2^, and E~c~ = 11.2 kV/cm, with a high Curie temperature (T~C~) of about 388 °C. Our results suggest that KNNBF/x are promising lead‐free high temperature piezoelectric ceramics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)