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Electrical Properties and Thermal Expansion Characteristics of (1- <i>x</i> )Ba <sub/>0.948</sub> Ca <sub/>0.05</sub> Er <sub/>0.002</sub> Ti <sub/>0.94</sub> Zr <sub/>0.06</sub> O <sub/>3</sub> -( <i>x</i> )Pr Lead-Free Piezoelectric Ceramics Sintered at a Low-Temperature
摘要： (1 (cid:1) x)Ba0.948Ca0.05Er0.002Ti0.94Zr0.06O3–(x)Pr (x ? 0–0.75 mol%) ceramics are sintered at 1240 (cid:3)C by conventional solid-state reaction method using the as-synthesized nanoparticles, which are prepared by a modified Pechini method. The structural, morphological, electrical, and thermal expansion properties as a function of varying x are systematically investigated. All samples feature rhombohedral phase, and their lattice parameters are accurately calculated by Rietveld refinement software. Volume of oxygen vacancies initially decreases and then increases with increasing x, leading to diversified electrical properties. Deteriorated electrical properties of the ceramics with excessive x are attributed to the increment of defect complexes with a large volume of oxygen vacancies. The coefficient of thermal expansion values of the ceramics that is influenced by phase evolution and structure defects under different temperature ranges are studied. The respective optimal electrical properties, that is, d33 ? 186 pC N mol%. This research is believed to be insightful to practical application of the lead-free multifunctional electron components.
关键词： thermal expansion coefficient,defect complexes,praseodymium-doping,BCEZT ceramics,piezoelectricity
更新于2025-09-23 15:21:21
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Defect-relevant piezoelectric and ferroelectric properties in LiCuTa3O9-doped K0.5Na0.5NbO3 lead-free piezoceramics
摘要： Lead-free K0.5Na0.5NbO3 + x mol LiCuTa3O9 (abbreviated to KNN-xLCT) piezoceramics are synthesized via a conventional sintering technique. All ceramics exhibit perovskite structure and their densification is improved after the addition of LCT. The doping of small quantities of LCT (x ≤ 0.015) results in the generation of two sorts of defect complexes [i.e., ?? V??(Cu???o ) ], inducing greatly hardening electrical behaviors with high mechanical quality factor Qm of ~ 780 at x = 0.015. However, excess LCT (x ≥ 0.015) contributes to the substantial reduction of defect complexes, and thus the ceramics are softened, presenting a relatively low Qm of ~ 480 at x = 0.03. It is noted that the ceramics with x = 0.03 remain comparatively great piezoelectric performances: d33 = 96 pC/N and kp = 37%. Our study indicates that the electrical properties of KNN-based ceramics doped with LCT are closely related with microscopic defect structure in the materials.
关键词： Lead-free piezoceramics,K0.5Na0.5NbO3,Piezoelectric properties,Defect complexes,LiCuTa3O9
更新于2025-09-23 15:19:57