Piezoelectric properties of CuO-added (Na0.5K0.5)NbO3 ceramic multilayers

Abstract

Multilayered ceramics (MLCs) laminated with 20 layers of CuO-added (Na0.5K0.5)NbO3 (CNKN) tape were well sintered at 960 degrees C with an average grain size of 5.0 mu m. They exhibited good piezoelectric properties of epsilon(T)(33)/epsilon(0) = 709, d(33) = 114 pC/N, k(p) = 0.34 and Q(m) = 793. The 80Ag/20Pd electrodes were well formed on the CNKN MLCs when they were co-fired at 960 degrees C for 2 h. A piezoelectric speaker fabricated using 6-layer CNKN MLCs exhibited an average sound pressure level (SPL) of 75 dB in the range between 300 and 20,000 Hz with a maximum SPL of 90 dB. This value is comparable with that of a loud stereo radio, indicating that the CNKN MLC is a good candidate material for piezoelectric speakers.