Enhanced Piezoelectric Properties of CaBi_2Nb_2O_9 with Eu Modification and Templated Grain Growth

摘要

Calcium bismuth niobate (CaBi_2Nb_2O_9, CBN) is a high Curie temperature (Tc) piezoelectric material, however, their piezoelectric properties are very poor. In order to improve the piezoelectric performance of CBN, the Eu modification and texture method (templated grain growth, TGG) were applied in this material system. The piezoelectric properties of CBN ceramics were significantly enhanced by Eu modification. The 5mol% Eu dopants in CBN ceramics have a higher piezoelectric constant and higher Tc (d_(33)=12.8pC/N, Tc=945°C) than that of undoped CBN ceramics (d_(33)=6.2pC/N, Tc=930°C). Highly textured 5mol% Eu doped CBN ceramics with 92% Lotgering factor were obtained by the TGG technique. The piezoelectric properties of textured and modified CBN ceramics are anisotropic on different directions of perpendicular (d_(33)=0.1pC/N) and parallel (d_(33)=20.5pC/N) to tape stacking direction. Furthermore, they had excellent thermostable piezoelectric properties from room temperature to near Curie temperature. The textured Eu modified CBN ceramics with high Tc and high piezoelectric properties might be a promising candidate for high-temperature piezoelectric applications.