Quantitative microstructural analysis and piezoelectricity of highly dense,submicron-structured NaNbO3 ceramics from mechanically activated precursors |
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Authors: | A Moure T Hungría A Castro L Pardo |
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Affiliation: | 1. LPMC, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex, France;2. IM2NP, Université du Sud Toulon Var, Avenue de l''Univ., 83957 La Garde Cedex, France |
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Abstract: | We study in this work the processing of NaNbO3 ceramics prepared in a single thermal treatment of highly reactive precursors obtained by mechanical activation of different reagents, aiming to determine optimum conditions for piezoelectric ceramics production. Pressure-less sintering at 1200 °C leads to dense ceramics (<5% porosity) with poor mechanical stability, unsuitable for practical uses. Dense hot-pressed ceramics were also obtained at lower temperatures (900–1100 °C), all of them in the submicron range of average grain sizes (<400 nm). Their microstructure was quantitatively characterized and their elastic and electromechanical properties determined by an automatic iterative method from impedance measurements at resonance. A noticeable ensemble of piezoelectric and elastic properties (d33 = 38 pC N?1 and Np = 3252 kHz mm) was measured for hot-pressed ceramics, from precursors obtained by a combined route of wet-chemistry and mechanical activation, with a microstructure characterized by 0.4% residual porosity and a bimodal lognormal distribution of grain size. |
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