Influence of Ca 2 Nb 2 O 7 on the structure and electric properties of CaBi 2 Nb 2 O 9 -based piezoceramics

A series of piezoelectric ceramics with the formula (1− x )Ca 0.92 (LiCe) 0.04 Bi 2 Nb 2 O 9 + x Ca 2 Nb 2 O 7 (CBNLC–CNO- x, where x = 0, 0.05, 0.1, 0.15, 0.2) were prepared by a facile traditional solid-state reaction method. The phase structure, Raman spectra, microstructure, dielectric properties, electric properties, piezoelectric properties and thermal stabilities of the obtained CBNLC–CNO- x ceramics were studied. X-ray diffraction revealed that the obtained ceramics had a typical bismuth layer structure with secondary phases of Ca 2 Nb 2 O 7 . The Rietveld refinement and Raman spectra revealed a lattice distortion in the CBNLC–CNO- x ceramics, which influenced the piezoelectric properties. Scanning electron microscopy indicated that the grain size of the ceramics gradually decreased with increasing x value. The Curie temperature ( T c ) of the ceramics was retained at an elevated temperature of approximately 926–940 °C and was close to that of pure CBN. The obtained ceramics showed great thermal stabilities, relative densities, dielectric properties and piezoelectric properties, which are beneficial for high-temperature applications.