Enhanced Piezoelectric Properties of CaBi₂Nb₂O₉ with Eu Modification and Templated Grain Growth

Abstract

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.

Enhanced electrical properties in W/Cu co‐doped CaBi2Nb2O9 high‐temperature piezoelectric ceramics

“…Obviously, below 800℃, all the W/Cu co‐doped specimens exhibited resistivity that was superior to that of the pure specimen, and this indicates that W/Cu doping effectively promotes resistivity. A comparison of d 33 and ρ (@600℃) obtained in this study with those of reported CBN ceramics is presented in Figure 8B 7,9,11,12,16,17,29,36‐40 . Apparently, high piezoelectricity and high‐temperature resistivity are simultaneously achieved in this study, showing that the material has advantages for potential high‐temperature piezoelectric application.…”

“…A comparison of d 33 and ρ (@600℃) obtained in this study with those of reported CBN ceramics is presented in Figure 8B. 7,9,11,12,16,17,29,[36][37][38][39][40] Apparently, high piezoelectricity and high-temperature resistivity are simultaneously achieved in this study, showing that the material has advantages for potential high-temperature piezoelectric application.…”

Significantly enhanced dc electrical resistivity and piezoelectric properties of Tb‐modified CaBi2Nb2O9 ceramics for high‐temperature piezoelectric applications

“…These undesirable factors make CBN unsuitable for high‐temperature applications. In order to overcome these drawbacks of CBN ceramic materials, several approaches have been developed to improve the electrical properties, such as compositions adjusting and grain orientation techniques 12–14 . Compositions adjusting by elements modifications is considered an effective approach to tailor the crystalline structure and microscopic morphology and thereby can effectively improve the piezoelectric and electrical properties of CBN 15–18 .…”

“…In order to overcome these drawbacks of CBN ceramic materials, several approaches have been developed to improve the electrical properties, such as compositions adjusting and grain orientation techniques. [12][13][14] Compositions adjusting by elements modifications is considered an effective approach to tailor the crystalline structure and microscopic morphology and thereby can effectively improve the piezoelectric and electrical properties of CBN. [15][16][17][18] For example, the (Li, Ce, Y)-modified CBN exhibits enhanced piezoelectric performance with a piezoelectric coefficient d 33 of 16.3 pC/N because of the octahedral tilt, and it also exhibits enhanced dc electrical resistivity, larger by one order of magnitude than unmodified CBN.…”

Enhanced electrical properties and conduction mechanism of A-site rare-earth Nd-substituted CaBi2Nb2O9

“…Nevertheless, CBN ceramics exhibit very low piezoelectric properties with a piezoelectric constant d 33 of ∼5 pC N −1 , as a result of the limitation of domain switching by the layered crystal structure. Therefore, different preparation methods have been adopted to enhance the piezoelectric properties of CBN-based ceramics [14][15][16][17][18][19][20][21][22][23]. Composition adjustment and grain-orientation techniques can improve the piezoelectric properties of CBN, and a piezoelectric constant d 33 of ∼20 pC N −1 can be achieved by grain orientation techniques or composition adjustment [22][23][24].…”