Structure and Piezoelectric Properties of (K,Na)NbO₃ Ceramics Fabricated from Microwave Hydrothermal Synthesized Powders

Abstract:

First, (K,Na)NbO₃ (abbreviated as KNN) powders were synthesized by microwave hydrothermal method using Nb₂O₅, NaOH and KOH as raw materials. The effects of NaOH/KOH mole ratio and reaction temperature on the structure of KNN powders were studied systematically. Near spherical KNN powders of about 800 nm in diameter can be obtained at the optimized processing parameters as follows: NaOH/KOH mole ratio was 1.40/4.60, reaction temperature was 200 °C. Second, the ceramics were successfully prepared from the microwave hydrothermal synthesized KNN powders under 1090 °C for 2 h. This ceramic sample showed the enhanced piezoelectric properties such as piezoelectric constant d₃₃=142 pC/N and planar electromechanical coupling coefficient k_p=38%, in addition to other good properties as relative dielectric constant ε_r=426, Curie temperature T_c=410 °C, remnant polarization P_r=17.45μC/cm² and coercive field E_c=1.41 kV/mm, indicating that microwave hydrothermal method can improve the properties of KNN ceramics high efficiently.

• Periodical: Advanced Materials Research (Volume 412)
• Pages: 285-289
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.412.285
• Online since: November 2011
• Authors: Yue Ming Li, Zong Yang Shen, Hu Liu, Zhu Mei Wang, Yan Hong
• Keywords: KNN, Lead-Free, Microwave Hydrothermal, Piezoelectric Ceramic (PZT)

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