Abstract: (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 (abbreviated as BCHT)lead-free piezoelectric ceramics were prepared successfully using a solid state reaction method.The effects of calcining temperature (1100~1250 ℃) on the microstructure and electrical properties of the BCHT ceramics were investigated.The results indicate that all the samples possess a pure perovskite phase structure.The phase structure of the sample change from tetragonal phase to rhombohedral phase around room temperature with increased calcining temperature, and the rhombohedral phase and tetragonal phase coexist in the composition range of 1150~1250 ℃.Meanwhile, the piezoelectric constant d33, remnant polarization Pr first decrease and then increase,and dielectric constant εr , diffusion coefficient γ first increase and then decrease,the coercive field Ec decreased with increasing the amount of calcining temperature.The comprehensive properties of (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 exhibits optimum value at 1250 ℃: d33=525 pC/N, Pr=10.2 μC /cm2, Ec=1.30 kV/cm, and εr =17699, γ=1.65, which indicates that the ceramic has a good application prospect.

Key words: (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 (abbreviated as BCHT)lead-free piezoelectric ceramics were prepared successfully using a solid state reaction method.The effects of calcining temperature (1100~1250 ℃) on the microstructure and electrical properties of the BCHT ceramics were investigated.The results indicate that all the samples possess a pure perovskite phase structure.The phase structure of the sample change from tetragonal phase to rhombohedral phase around room temperature with increased calcining temperature, and the rhombohedral phase and tetragonal phase coexist in the composition range of 1150~1250 ℃.Meanwhile, the piezoelectric constant d33, remnant polarization Pr first decrease and then increase,and dielectric constant εr , diffusion coefficient γ first increase and then decrease,the coercive field Ec decreased with increasing the amount of calcining temperature.The comprehensive properties of (Ba0.85Ca0.15)(Ti0.9Hf0.1)O3 exhibits optimum value at 1250 ℃: d33=525 pC/N, Pr=10.2 μC /cm2, Ec=1.30 kV/cm, and εr =17699, γ=1.65, which indicates that the ceramic has a good application prospect.