Enhanced Curie temperature and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3 lead-free ceramics after the addition of LiTaO3

Abstract

Polycrystalline (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3–xLiTaO3 ceramics were designed and synthesized using a solid-state reaction to improve both the Curie temperature and the electrical properties of (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3 lead-free piezoelectric ceramics. The effect that the addition of LiTaO3 has on the structure and electrical properties of BCZT ceramics was studied systemically. The results show that the Curie temperature and the piezoelectric properties of BCZT can be substantially enhanced by adding LiTaO3. The Curie temperature increased from 93 °C to 102 °C after adding LT of 0.3 mol.%. X-ray diffraction and Raman spectral analysis of the ceramics reveal the coexistence of orthorhombic (O) and tetragonal (T) phases. This coexistence of O and T phases at room temperature helps improve the ferroelectric and piezoelectric properties. The ceramic with x = 0.3 mol.% exhibits the highest values for d33 = 433 pC/N, d33* = 858 pm/V (at 1 kV/mm) and kp = 44.6%. Furthermore, giant electrostrictive coefficients (Q33 ≈ 0.040–0.050 m4/C2) were also obtained for these LT-doped BCZT ceramics. These properties confirm that BCZT-xLT is a promising candidate system for lead-free piezoelectric ceramic materials.