A low sintering temperature is achieved for (Ba0.85Ca0.15)(Ti0.90Zr0.10)O-3 (BCZT) piezoelectric ceramics using Ba(Cu0.3W0.5)O-3 (BCW) as a sintering aid. The effects of the BCW content on the density, phase structure, electrical and mechanical properties are investigated. The addition of BCW content significantly improves the sinterability of the BCZT ceramics, which results in a reduction of the sintering temperature from 1450 degrees C to 1220 degrees C and an improvement in both the piezoelectric and mechanical properties. The BCZT ceramics with x = 0.8 wt.% BCW sintered at 1220 degrees C exhibits outstanding piezoelectric, dielectric and mechanical properties: d(33) = 541 pC/N, k(p) = 49%, Q(m) = 107, epsilon(r) = 5405, tan delta = 0.014 and T-c = 78 degrees C. The ceramics also exhibit higher hardness (78 MPa) and higher fracture toughness (4.7 MPa m(1/2)). These results indicate that the BCZT-BCW lead-free ceramics sintered at low temperatures are promising for high temperature piezoelectric applications. (C) 2015 Elsevier Ltd. All rights reserved.