超声换能器环氧树脂-氧化铝匹配层研究

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 1 136 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。

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

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 1 136 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.