TY - JOUR AB - (K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders. AU - Isobe, G. AU - Maeda, Takafumi AU - Bornmann, Peter AU - Hemsel, Tobias AU - Morita, Takeshi ID - 9878 IS - 2 JF - Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on KW - Q-factor KW - ceramics KW - crystal growth from solution KW - particle size KW - piezoelectric materials KW - potassium compounds KW - powders KW - sintering KW - sodium compounds KW - ultrasonic effects KW - (K0.48Na0.52)NbO3 KW - KNbO3 powders KW - NaNbO3 powders KW - high-power ultrasonic irradiation KW - lead-free piezoelectric materials KW - lead-free piezoelectric powders KW - particle size reduction KW - piezoelectric properties KW - quality factor KW - sintered (K0.48Na0.52)NbO3 ceramics KW - sintering KW - ultrasonic-assisted hydrothermal method KW - Acoustics KW - Ceramics KW - Lead KW - Piezoelectric materials KW - Powders KW - Radiation effects KW - Transducers SN - 0885-3010 TI - Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics VL - 61 ER - TY - CONF AB - A hydrothermal method utilizes a crystallization process in the solution so that the pure and high-quality powders can be realized. Sintering from the hydrothermal KNbO3 and NaNbO3 powders, a high-dense lead-free piezoelectric (K,Na)NbO3 ceramics could be obtained (density: 98.8\%). Concerning about the g33 constant, high value as large as commercial PZT ceramics was measured. Therefore, the hydrothermal (K,Na)NbO3 ceramics is usable for the sensors and the energy harvesting devices. To demonstrate the (K,Na)NbO3 ceramics, a hydrophone sensor was fabricated and evaluated. AU - Maeda, Takafumi AU - Bornmann, Peter AU - Hemsel, Tobias AU - Morita, Takeshi ID - 9788 KW - crystallisation KW - hydrophones KW - piezoceramics KW - potassium compounds KW - powder technology KW - powders KW - sensors KW - sintering KW - sodium compounds KW - (K0.48Na0.52)NbO3 KW - KNbO3 powder KW - NaNbO3 powder KW - crystallization KW - energy harvesting devices KW - g33 constant KW - hydrophone sensor KW - hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics KW - hydrothermal method KW - piezoelectric applications KW - sintering KW - Materials KW - Transducers SN - 1948-5719 T2 - Ultrasonics Symposium (IUS), 2012 IEEE International TI - Piezoelectric applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics ER -