Effect of Different Ca2+ and Zr4+ Contents on Microstructure and Electrical Properties of (Ba,Ca)(Zr,Ti)O3 Lead-Free Piezoelectric Ceramics

Abstract

In the preparation of (Ba,Ca)(Zr,Ti)O3 lead-free piezoelectric ceramics, different Ca2+ and Zr4+ contents will greatly affect the phase structure, microstructure, and electrical properties of the ceramics. XRD shows that all samples have pure perovskite phase structure, and the (Ba0.85Ca0.15)(ZryTi1−y)O3 ceramics morphotropic phase boundary region from tetragonal phase to rhombohedral phase near 0.08 ≤ y ≤ 0.1. From the dielectric temperature curve, the phase transition temperature (TO-T) was found near room temperature at 0.12 ≤ x ≤ 0.18 for the (Ba1−xCax)(Zr0.1Ti0.9)O3 ceramics. Both Ca2+ and Zr4+ increase have a significant decrease on the Curie temperature Tc. All samples were revealed as relaxers with diffusivities in the range 1.29 ≤ γ ≤ 1.82. Different from the undoped ceramics, ceramics doped with Ca and Zr ions exhibit saturated P–E hysteresis loops, and their ferroelectric properties are significantly optimized. In particular, the (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramic demonstrated optimal properties, namely d33 = 330 pC/N, kp = 0.41, εr = 4069, Pr = 4.8 μC/cm2, and Ec = 3.1 kV/cm, indicating that it is a viable lead-free piezoelectric contender. Variations in Ca and Zr content have a significant effect on the crystal grain sizes and densities of ceramics, which is strongly associated with their piezoelectricity.

Understanding Crystal Spatial Symmetry of Sm/Mg Heterovalent‐Doped BST–BNT Ceramics: An Effect Mechanism for Electrical Properties

“…Based on the order of magnitude in C values, the paraelectric phase of ceramic materials was driven by a displacement-type transition at high temperatures. [44,45] The BST-BNT: x(Sm, Mg) (x = 0.10 wt%) ceramics acquired maximum Curie-Weiss eigenvalues ΔT m = 43.0 °C, which indicated the highest FE relaxation degree. This finding is consistent with the frequency dependence of the T C , as earlier observed in the current study.…”

Chemical-Composition Tuning-Enabled Optimization of Structure, Properties, and Performance of Lead-Free (1 – x)BaZr0.05Ti0.95O3–(x)Ba0.92Ca0.08TiO3 Electroceramics

“…26 The Ca 2+ and Zr 4+ substitutions, respectively, for Ba 2+ and Ti 4+ in BaTiO 3 ceramics, significantly modify the grain size, densities, and microstructure, which are important factors to tailor the dielectric, ferroelectric, and piezoelectric properties. 27 Thus, the (Ba,Ca)(Zr,Ti)O 3 ceramics are expected to demonstrate optimal properties, making them feasible lead-free piezoelectric competitors. In this connection, Yoon and Ur have explored advancements in enhancing dielectric properties of a ceramic material comprising BaTiO 3 −CaTiO 3 .…”

“…Further, the presence of nearby room-temperature phase transition makes BZT a suitable material for biomedical and underwater applications . The Ca 2+ and Zr 4+ substitutions, respectively, for Ba 2+ and Ti 4+ in BaTiO 3 ceramics, significantly modify the grain size, densities, and microstructure, which are important factors to tailor the dielectric, ferroelectric, and piezoelectric properties . Thus, the (Ba,Ca)­(Zr,Ti)­O 3 ceramics are expected to demonstrate optimal properties, making them feasible lead-free piezoelectric competitors.…”