High temperature piezoelectric BiScO3-PbTiO3 synthesized by mechanochemical methods

Mechanochemical methods have been demonstrated to be an effective means of synthesizing nanocrystalline high sensitivity piezoelectric low tolerance factor perovskites capable of providing enough material to carry out systematic studies on the processing of ceramics and on their properties. Here BiScO3-PbTiO3 is used as a model system of general BiMO3-PbTiO3 perovskite solid solutions with ferroelectric morphotropic phase boundaries and a high Curie temperature to describe mechanochemical effects on the properties of the ceramic materials. These effects are shown to be the consequence of perovskite crystalline strain accumulated during milling and of accidental Fe-sc(x) doping from the medium, and cause no significant degradation of the electrical and piezoelectric properties of ceramics that are fully functional. The high temperature actuation characteristics of morphotropic phase boundary BiScO3-PbTiO3 ceramics are described for the first time. The room temperature response is highly linear, with an effective piezoelectric coefficient of 380 pC N-1, and materials maintain the high piezoelectric response up to 400 degrees C. Hysteresis and effective coefficients significantly increase at 300 degrees C up to values above 1000 pC N-1, which is shown to be associated with the onset of large extrinsic contributions. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.