(Bi0.5Na0.5)0.94Ba0.06TiO3 / P(VDF-TrFE) 0-3 Composites Poled with a Sinusoidal Electric Field

Abstract

Bismuth sodium barium titanate [(Bi0.5Na0.5)0.94Ba0.06TiO3 or BNBT6] ceramic powder have been incorporated into a polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE) 70/30 mol%] copolymer matrix to form 0-3 composites. With the composition near the morphtrophic phase boundary (MPB) region, BNBT6 has relatively high piezoelectric properties. Polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] is a ferroelectric copolymer that has high piezoelectric and pyroelectric performance. BNBT6/P(VDF-TrFE) 0-3 composites with BNBT6 volume fraction Phi ranging from 0.05 to 0.3 were prepared using solvent casting to disperse the ceramic powder in the copolymer matrix followed by hot-pressing. The pyroelectric coefficient of the composites was measured as a function of Phi under different A.C. poling conditions. As both the BNBT6 inclusion and P(VDF-TrFE) matrix can be poled under similar conditions, the composites can be poled effectively after subjected to several cycles of sinusoidal electric field. The BNBT6 0-3 composites (poled with a.c. source) were found to have better pyroelectric properties than that of lead zirconate titante PZT / P(VDF-TrFE) 0-3 composites (poled with d.c. source).