Fabrication of grain-oriented PbNb2O6-based high temperature piezoelectric ceramics

Abstract

Grain-oriented Sr and Ti modified lead metaniobate (Pb0.96Sr0.04)Nb1.96Ti0.05O6 (PSNT) ceramics with 4 mol% excess of Nb2O5 were prepared by templated grain growth method. The needle-like PSNT templates were obtained through the molten salt synthesis method. The effects of the template concentration (5, 10, 20 and 30 wt%) on the texture degree, microstructure, and electrical properties of textured ceramics were investigated. Improved electromechanical properties were found along the direction perpendicular to the sheet in textured PSNT ceramics, which shows the preferential orientation. An excess of templates would seriously deteriorate the properties of textured ceramics. The textured PSNT ceramics with 5 wt% templates exhibit high Curie temperature Tc of 545 °C, and improvement in piezoelectric coefficient d33 by 9% (d33 = 98 pC/N) and g33 by 45% (g33 = 42 × 10−3 Vm/N), as well as electromechanical coupling coefficient k31 by 18% (k31 = 0.26) compared to randomly oriented ceramics. The study demonstrates that grain-orientation controlling in PN-based ceramics is a potential way to improve the piezoelectric properties while maintaining high Curie temperature.