Enhanced electrical resistivity and mechanical properties in BCTZ-based composite ceramic

Abstract

Environmental and human health concerns about lead toxicity have prompted the development of lead-free piezoceramics. Among them, (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCTZ) with excellent piezoelectric properties has the most potential and attracts extensive attention. However, lack of concern toward electrical resistivity and mechanical properties has greatly hindered its practical application. Here, we report the achievement of enhanced insulation characteristics (grain electrical resistivity increased by one order of magnitude) and superior mechanical properties (Vickers hardness value increased by 40%) in Al2O3-added BCTZ composite ceramics. Such improvement can be attributed to specific composite microstructure, where the nonferroelectric second phase dispersed in the grain interior and grain boundary of BCTZ matrix results in blocking effect on the electric current paths as well as propagation of microcracks. These findings will pave a new way for the practical application of BCTZ ceramics.