纳米填充硅橡胶超声干耦合特性*

针对工业超声无损检测领域干耦合材料种类匮乏，且声能透射率低的问题，论文在室温硫化硅橡胶基底材料中添加不同成份和配比的纳米颗粒，制备了不同种类的干耦合材料，给出了干耦合条件下超声波的传输模型，得到了声学传输规律，对比分析了干耦合材料种类、厚度、硬度、超声中心频率及载荷因素对声能传输特性的影响。搭建了声学特性测试实验平台，分别对添加氧化铝、铁和二氧化硅纳米颗粒制备的干耦合材料进行了测定，试验结果表明填充二氧化硅质量分数为5%时，所形成的纳米填充硅橡胶的声阻抗提高了13.5%，使用200kPa预载荷对试块测量时回波幅值提高了18.0%，具有良好的声耦合性能。可为实际超声检测时干耦合材料的制备及应用提供参考。

The ultrasonic dry coupling characteristics of nano-filled silicone rubber

In order to overcome the shortage of dry coupling materials and low transmittance of sound energy in the field of industrial ultrasonic nondestructive testing, different kinds of dry coupling materials were prepared by adding different nanoparticles with different composition and ratio in room temperature vulcanized silicone rubber base materials. The ultrasonic transmission model under dry coupling conditions was given and the law of acoustic transmission was obtained. The influence of different dry coupling materials, thickness, hardness, center frequency of ultrasound and load on the acoustic energy transfer performance is compared and analyzed. An experimental platform for testing the acoustic properties was set up. The dry coupling materials prepared by adding alumina, iron and silicon dioxide nanoparticles were measured. The results show that the acoustic impedance of the nano-filled silicone rubber increased by 13.5% when the mass fraction of filled silicon dioxide is 5%, and the echo amplitude increased by 18.0% when the pre-load of 200 kPa was used. Therefore, it has good acoustic coupling performance than other materials. This research can provide reference for the preparation and application of dry coupling materials in the actual ultrasonic testing.