用于高频超声换能器应用的氧化铝/环氧树脂纳米复合匹配层。
Alumina/epoxy nanocomposite matching layers for high-frequency ultrasound transducer application.
作者信息
Zhou Qifa, Cha Jung Hyui, Huang Yuhong, Zhang Rui, Cao Wenwu, Shung K Kirk
机构信息
Department of Biomedical Engineering and NIH Transducer Resource Center, University of Southern California, Los Angeles, CA, USA.
出版信息
IEEE Trans Ultrason Ferroelectr Freq Control. 2009 Jan;56(1):213-9. doi: 10.1109/TUFFC.2009.1021.
Mismatch of acoustic impedance at the interface between a piezoelectric transducer and the medium to be probed will substantially reduce the amount of ultrasound energy being transmitted into the medium. Therefore, matching layer is a critical component of an ultrasonic transducer. A spin-coating process was used to fabricate alumina/polymer nanocomposite films with alumina volume fractions ranging from 14 to 32%. The particle size of alumina is in the range of 10 to 40 nm. The thicknesses of the matching layer can be controlled by the spinning speed and the concentration of solution. Acoustic impedances of these nanocomposite matching layers are in the range of 2.8 to 5.1 MRayls with different alumina contents, which meet the matching layer requirement. The attenuation of a nanocomposite matching layer with smooth surface is about 15 dB/mm at 40 MHz. The pulse-echo spectrum and frequency spectrum of a high-frequency transducer using this nanocomposite matching layer are reported.
压电换能器与被探测介质之间界面处的声阻抗失配会大幅降低传输到介质中的超声能量。因此，匹配层是超声换能器的关键部件。采用旋涂工艺制备了氧化铝体积分数在14%至32%之间的氧化铝/聚合物纳米复合薄膜。氧化铝的粒径在10至40纳米范围内。匹配层的厚度可通过旋转速度和溶液浓度来控制。这些纳米复合匹配层的声阻抗在2.8至5.1兆瑞利之间，不同氧化铝含量均满足匹配层要求。表面光滑的纳米复合匹配层在40兆赫兹时的衰减约为15分贝/毫米。报道了使用这种纳米复合匹配层的高频换能器的脉冲回波频谱和频率频谱。
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