Fabrication and Properties of Lead-free Piezoelectric Buzzers Made from K0.5Na0.5NbO3-based Ceramics

摘要

Lead-free piezoelectric buzzers based on (K0.975Li0.025Na0.5)Nb0.95Sb0.05O3 (KLNNS2.5-5) ceramics were fabricated and their properties were investigated. The KLNNS2.5-5 ceramic membranes with diameter of 15–16 mm and thickness of 0.10–0.11 mm were prepared by the roll forming process. The electrical properties of the lead-free piezo-ceramic membranes are kp=0.445, d33=150 pC/N, εr=466 (at 1 kHz), and tan δ=0.033 (at 1 kHz). The resonance frequency (fr) of the super-thin buzzer disks is about 4.68 kHz. The sound pressure level (SPL) of the KLNNS2.5-5 buzzers reaches 84.2 dB at 2 kHz, and reaches a maximum value of 88.8 dB at 2.81 kHz, which are comparable to that of the lead-based ones. The electro-acoustic properties of the KLNNS2.5-5 buzzers can basically satisfy the requirements (≥ 80 dB) of microwave ovens applications. Results show that the KLNNS2.5-5 ceramics are promising candidates for practical application in buzzers.