Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications
Open Access
- 6 December 2019
- Vol. 19 (24), 5383
- https://doi.org/10.3390/s19245383
Abstract
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.Keywords
Funding Information
- Ontario Centres of Excellence (29033)
This publication has 11 references indexed in Scilit:
- High temperature EMAT design for scanning or fixed point operation on magnetite coated steelNDT & E International, 2017
- High temperature thickness measurements of stainless steel and low carbon steel using electromagnetic acoustic transducersNDT & E International, 2014
- Development of a high temperature transducer backing element with porous ceramicsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2014
- Full-Wave Iterative Image Reconstruction in Photoacoustic Tomography With Acoustically Inhomogeneous MediaIEEE Transactions on Medical Imaging, 2013
- Photoacoustic computed tomography correcting for heterogeneity and attenuationJournal of Biomedical Optics, 2012
- The Application of Ultrasonic NDT Techniques in TribologyProceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2005
- The Use of Ultrasound in the Investigation of Rough Surface InterfacesJournal of Tribology, 2000
- A study of the transmission of ultrasound across solid–rubber interfacesThe Journal of the Acoustical Society of America, 1997
- A study of the interaction between ultrasound and a partially contacting solid—solid interfaceProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1996
- Prediction of contact parameters using ultrasonic methodWear, 1991