Influence of CuO addition on dielectric and piezoelectric properties of (Bi 0. 5 Na 0. 5) TiO 3 - BaTiO 3 lead-free piezoceramics

Abstract

Doping effects of CuO on the sintering behavior and electrical properties of 0.94(Bi0.5Na0.5)TiO3-0.06(BaTiO3)-xCuO (BNT-BT6-xCu) lead-free piezoceramic obtained by the conventional solid-state reaction method were investigated. Regarding the undoped system, it is already known that it presents the best densification values when it is sintered at 1150°C, however, the doped system was sintered at 1150°C, 1100°C, 1050°C, 1025°C, and 975°C to determine the effect of Cu on the densification process. Therefore, it was obtained that the CuO-doped samples sintered at 1050°C presented the highest density values and therefore were the ones chosen to perform the characterization tests together with the undoped system. The samples were characterized using X-ray diffraction (XRD), Raman microspectroscopy, and scanning electron microscopy (SEM) analysis, whereas the ferroelectric and dielectric properties were evaluated by means of ferroelectric hysteresis loops and impedance spectroscopy studies. As a result, the addition of CuO allowed an improvement in sinterability and densification, with the subsequent grain growth, and the improvement of the piezoelectric coefficient (d33).