超声换能器环氧树脂-氧化铝匹配层研究

Study of the epoxy-alumina composite based matching layer for ultrasonic transducer

匹配层对超声换能器的性能起着至关重要的作用,寻找合适的匹配层材料是换能器设计中的关键步骤。提出了一种基于环氧树脂-氧化铝复合材料的匹配层材料。首先,测试了不同配比的环氧树脂-氧化铝复合材料的声学性能,对比了其声学特性,并确定了材料的最佳配比。其次,研制了相应的换能器,分析该匹配层对换能器性能的影响,通过脉冲-回波方法测试了其性能参数。最后,基于四分之一波长匹配层原理对匹配层的厚度进行了优化。结果显示,环氧树脂中加入质量分数为60%的氧化铝粉末的匹配层对换能器的改善效果最佳,该方案减小了换能器接收回波的拖尾,接收回波的幅值提高至1136 mV(+104%),−6 dB带宽达到49.679%(+107%)。结果表明,氧化铝-环氧树脂混合材料可以提升换能器的声学性能,是较为理想的匹配层材料,在高频超声换能器的设计与应用中具有很好的应用前景。

Matching layer is indispensable in an ultrasonic transducer.Finding suitable matching layer material is crucial in the procedure of transducer design.In this study,a matching layer material based on epoxy-alumina composite is proposed.The acoustic properties of epoxy-alumina composites with different proportions are firstly tested and compared,and the optimal proportion is determined.Then,transducers with epoxy-alumina composite based matching layer are developed,their performance parameters are measured by pulse-echo method.Finally,the thickness of the matching layer is optimized based on the quarter-wavelength theory.The results demonstrate that the matching layer with the mass fraction of 60%of alumina powder provides the best improvement in the transducer performance;the tail of the received echo pulse is reduced,the amplitude is increased to 1136 mV(+104%),and the−6 dB bandwidth can reach 49.679%(+107%).All the results indicate that this epoxy-alumina composite material can improve the performance of transducer,and has a great application potential in the design of high frequency ultrasonic transducer.