Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48N.52)NBO3 ceramics
G. Isobe, T. Maeda, P. Bornmann, T. Hemsel, T. Morita, Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On 61 (2014) 225–230.