Microstructure related properties enhancing in Ce-doped CaBi2Nb2O9 high temperature piezoelectric ceramics

Abstract

CexCa1−xBi2Nb2O9 (CCBN, x = 0 ∼ 0.08) bismuth layered structural piezoceramics with pure orthorhombic symmetry were fabricated by conventional processing method. The microstructure of CCBN ceramics was obviously correlated with Ce doping content. Small Ce doping content (x ≤ 0.04) suppressed the sheet morphology of the ceramics, in favor of forming small particle-like grains. However, the grains grown and turned into sheet structure again when Ce doping content x ≥ 0.06. The CCBN ceramics with Ce doping content x = 0.04, owing to its microstructure of small and uniform particle-like grains, exhibited enhancing properties as follows: piezoelectric constant d33 = 10.3 pC/N, planar electromechanical coupling coefficient kp = 11.5%, dielectric constant = 106, and dielectric loss tanδ = 0.28%. In addition to high resistivity (ρ = 8.7 × 107 Ω cm at 500 °C) and good thermal stability up to 800 °C, this ceramic sample should very promising for high temperature sensing applications.