Increased thermal stability by the addition of ZrO2 into a 0.48Ba(Zr0.2Ti0.8)O3-0.52(Ba0.7Ca0.3)TiO3 matrix material

Abstract

Ferroelectric ceramics based on x(Ba0.7Ca0.3)TiO3–(1−x)Ba(Zr0.2Ti0.8)O3 (BCZT100x) are regarded as promising lead-free candidates for piezoelectric applications. Heightened piezoelectric properties are found around specific temperatures, i.e. polymorphic phase boundaries. As broader thermal stability is required for certain applications, this study aims to increase the diffusiveness of the phase transitions by introducing ZrO2 as a filler material into a BCZT52 matrix. The diffuseness factor of the Curie point was evaluated and increased from approximately 1.60 to 1.88 with the addition of 4 vol% ZrO2 to BCZT52. As a result, samples with an additional 2 vol% showed the highest thermal stability in the temperature range between 25 °C and 70 °C. Here, the large signal piezoelectric strain coefficient d33* degraded only by 18%, compared to 30% in BCZT52. This increase was caused by the inhomogeneous distribution of Zr within the sample.