Japanese Journal of Applied Physics · 2007 · 197 citations · 16 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsCeramicsMaterials CharacterizationCeramic MorphologyCeramic TechnologyFerroelectric CeramicsPiezoelectric CeramicsPowder ProcessingSinteringAnisotropic Grain GrowthBarium TitanateBarium Titanate CeramicsCeramic SynthesisParticle Size EffectsPiezoelectric PropertiesVolume Fraction EffectsX-ray Diffraction Analysis
The study aimed to optimize preparation conditions—matrix particle size, template‑to‑matrix volume fraction, and sintering temperature—to achieve both high density and high [110] orientation (F110). Using templated grain growth, [110]-oriented BaTiO₃ platelike templates and hydrothermal BaTiO₃ spheres formed the matrix; orientation was quantified by X‑ray diffraction Lotgering analysis, and the resulting ceramics were poled at 100 °C and their piezoelectric constants measured by resonance–antiresonance and d33 meter techniques. The optimized ceramics exhibited densities above 96 % across F110 values of 0–98 %, uniform grain sizes of ~75 µm without anisotropic microstructures, d31 values near –50 pC/N regardless of F110, and d33 values that rose with F110, peaking at 788 pC/N.
[110]-oriented barium titanate (BaTiO3) ceramics were prepared by templated grain growth (TGG) method using [110]-oriented BaTiO3 platelike particles as a template and hydrothermal BaTiO3 sphere particles with different particle sizes as a matrix. The degree of orientation along the [110] direction, F110, was measured using an X-ray diffraction (XRD) pattern by the Lotgering method. To obtain both a high density and a high F110, the preparation conditions were optimized as functions of matrix particle size, volume fraction of the template to the matrix, and sintering temperature. As for the results, BaTiO3-grain-oriented ceramics with a high density of more than 96% were successfully prepared despite various F110 values from 0 to 98%. Scanning electron microscopy (SEM) revealed that their average grain sizes were always approximately 75 µm despite various F110 values and there were no anisotropic microstructures. These grain-oriented BaTiO3 ceramics were poled at 100 °C, and their piezoelectric properties were measured using a resonance–antiresonance method and a piezo d33 meter for d31 and d33 piezoelectric constants. As for the results, the d31 values were almost constant at -50 pC/N despite various F110 values, while the d33 values increased with increasing F110 values, and at around an F110 of 85%, d33 reached a maximum of 788 pC/N.
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