Piezoelectric K0.5Na0.5NbO3 Ceramics Textured Using Needlelike K0.5Na0.5NbO3 Templates |
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| Authors: | Astri Bjørnetun Haugen Gerhard Henning Olsen Francesco Madaro Maxim I Morozov Goknur Tutuncu Jacob L Jones Tor Grande Mari‐Ann Einarsrud |
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| Affiliation: | 1. Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), , Trondheim, Norway;2. Department of Materials Science and Engineering, University of Florida, , Gainesville, Florida;3. Department of Materials Science and Engineering, North Carolina State University, , Raleigh, North Carolina |
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| Abstract: | Improved performance by texturing has become attractive in the field of lead‐free ferroelectrics, but the effect depends heavily on the degree of texture, type of preferred orientation, and whether the material is a rotator or extender ferroelectric. Here, we report on successful texturing of K0.5Na0.5NbO3 (KNN) ceramics by alignment of needlelike KNN templates in a matrix of KNN powder using tape casting. Homotemplated grain growth of the needles was confirmed during sintering, resulting in a high degree of texture parallel to the tape casting direction (TCD) and the aligned needles. The texture significantly improved the piezoelectric response parallel to the tape cast direction, corresponding to the direction of the strongest <001>pc orientation, while the response normal to the tape cast plane was lower than for a nontextured KNN. In situ X‐ray diffraction during electric field application revealed that non‐180° domain reorientation was enhanced by an order of magnitude in the TCD, compared to the direction normal to the tape cast plane and in the nontextured ceramic. The effect of texture in KNN is discussed with respect to possible rotator ferroelectric properties of KNN. |
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