铌酸钾钠基无铅压电陶瓷纵振换能器*

高性能环境友好型无铅压电陶瓷及其应用是当前压电材料研究的热点之一，为了探究其在水声换能器领域的应用潜力，该文对铌酸钾钠基无铅压电陶瓷和锆钛酸铅压电陶瓷纵振式换能器进行了对比研究。依据仿真结果优化结构尺寸，制作了两种换能器样机并测试了其在空气中和水中的电声性能。测试结果表明，铌酸钾钠基无铅压电陶瓷换能器的谐振频率为35kHz，最大发送电压响应为 151dB，声源级可达 190dB，在 26kHz~67kHz 的频率范围内发送电压响应的起伏不超过±4.5dB，谐振频率处-3dB 的指向性开角约为 76°。该无铅压电陶瓷换能器具有和锆钛酸铅压电陶瓷换能器相当的发射性能，有望推动无铅压电材料在水声换能器领域的应用进程。

Potassium sodium niobate lead-free piezoelectric ceramic longitudinal vibration transducer

High-performance and environmentally-benign lead-free piezoelectric ceramics and their applications have been the spotlight in the researches on piezoelectric material at present. In order to explore its potential for application in underwater transducer, a comparative research between potassium sodium niobate lead-free piezoelectric ceramic and lead zirconate titanate piezoelectric ceramic longitudinal transducer is carried out. The structural dimensions are optimized by finite element analysis at first. Then two types of transducer prototypes are fabricated and their electro-acoustic performance both in air and underwater are measured. It could be found that the resonance frequency of lead-free piezoelectric ceramic transducer is 35kHz with the maximum transmitting voltage response of about 151dB. The source level could be over 190dB. The highest fluctuation of transmitting voltage response in the frequency range from 26kHz to 67kHz is no more than ±4.5dB. And the -3dB directivity angle at the resonance frequency is about 76°. The performance of lead-free piezoelectric ceramic transducer is confirmed to be comparable to that of the lead zirconate titanate piezoelectric ceramic transducer. It is expected to have further application in the field of underwater transducers.