Control of paste rheology and piezoelectric properties of Bi 0.5(Na0.82K0.18)0.5TiO3 Lead-free piezoelectric thick films deposited by screen printing

Abstract

Bi0.5(Na0.82K0.18)0.5TiO 3 (NKBT) lead-free thick films with a thickness of 10-100 Îm have been deposited on a Pt-electroded alumina substrate using screen printing. The influences of the NKBT particle size, NKBT powder content, binder concentration, and dispersant on the rheological characteristics were systematically investigated. The resulting 60 Îm thick films exhibit a dielectric constant of 582 (10 kHz), a dielectric loss of 2.8%, remanent polarization of 22.5 ÎC/cm2, a coercive field of 62 kV/cm, and a longitudinal effective piezoelectric coefficient, d33eff of 91 pm/V. The thick films are expected to be a new and promising candidate for lead-free piezoelectric microdevices especially the microactuator applications. © 2010 The American Ceramic Society.