Calcium bismuth niobate (CaBi2Nb2O9, 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 (d33=12.8pC/N, Tc=945°C) than that of undoped CBN ceramics (d33=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 (d33=0.1pC/N) and parallel (d33=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.
The bismuth layered structure materials (BLSFs) with general formula of the (Bi2O2)2+(Am-1BmO3m+1)2-, have attracted considerable attention for high-temperature piezoelectric applications. Hot pressing is a useful densifying and texture technique for enhancing the piezoelectric properties. In this present study, four different types (m=1, 2, 3, 4) of ceramics with Aurivillius structure were prepared and the influential factors of textured degree was investigated systematically by hot pressing method. The result indicates that the value of m is larger, the BLSFs ceramics is easier to get high degree of texture and high piezoelectric properties in the parallel of the hot pressing direction.
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