Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications
Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications
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DOI：
10.3390/s19245383
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发表时间：
2019-12-02
期刊：
影响因子：
3.9
通讯作者：
Sinclair, Anthony
中科院分区：
文献类型：
--
作者：
Bhadwal, Neelesh;Milani, Mina Torabi;Sinclair, Anthony
使用退火银的薄箔作为每个部件界面处的填充材料/偶联剂，研究了压电超声换能器部件的干耦合的可行性。用于室温评估的标准集中在信噪比（SNR）和回波带宽上，用于在脉冲回波模式下操作的Li-Nb基换能器。仅25 MPa的正常夹持应力，重复施加在三个加载循环上的精确对准的换能器叠层，足以产生SNR大于25 dB的后壁回波，以及约65%的3 dB带宽。相比之下，当所有换能器接口与超声凝胶耦合时，SNR为32 dB，3 dB带宽为65%。在实现这种高效率的干耦合中，评估了软填料材料、换能器组件对齐、循环夹紧、组件粗糙度和组件平整度的各自作用，换能器夹紧力远低于先前报道的。初步的高温测试表明，这种耦合方法适用于高温，并且可以达到与室温下超声凝胶相当的信号质量。
The viability for dry coupling of piezoelectric ultrasonic transducer components was investigated, using a thin foil of annealed silver as a filler material/coupling agent at each component interface. Criteria used for room temperature evaluation were centered on signal-to-noise ratio (SNR) and echo bandwidth, for a Li-Nb based transducer operating in pulse-echo mode. A normal clamping stress of only 25 MPa, applied repeatedly over three loading cycles on a precisely-aligned transducer stack, was sufficient to yield backwall echoes with a SNR greater than 25 dB, and a 3 dB bandwidth of approximately 65%. This compares to a SNR of 32 dB and a 3 dB bandwidth of 65%, achievable when all transducer interfaces were coupled with ultrasonic gel. The respective roles of a soft filler material, alignment of transducer components, cyclic clamping, component roughness, and component flatness were evaluated in achieving this high efficiency dry coupling, with transducer clamping forces far lower than previously reported. Preliminary high temperature tests indicate that this coupling method is suitable for high temperature and achieves signal quality comparable to that at room temperature with ultrasonic gel.