Abstract:
High Temperature Ultrasonic Transducers
Authors H. Mrasek, D. Gohlke, K. Matthies, E. Neumann, BAM, Berlin
Deutsch Die englische Version ist vollständiger
Transducer Workshop
Evaluation of reports and literature, contact with manufacturers and users of equipment
for ultrasonic testing in high temperature environment showed that at temperatures >200°C ultrasonic testing is based on
electromagnetically generated ultrasound using electromagnetically excited and contactlessly working ultrasonic transducers (EMAT)
[1-4] . No new paths of developing piezoelectric transducers could be found.
The knowledge gained from investigations on the different ultrasonic probe's components has been compiled and matched to give the
prototype probe introduced in this article.
The experiments made it clear, that the piezo ceramic, with respect to the tempera- ture, developed into a higher and higher sensitivity,
with an upper limit in the proxi- mity of 760°C-780°C. However, this upper limit seems to be of only theoretical importance, as at this
temperature the present echo is of too low a performance (signal/noise-ratio < 6dB) to be used in practice. Nevertheless, for ultrasonic
inspection, i. e. wall thickness measurement, this piezo ceramic will be applicable up to roughly 700°C.
Authors
K. Matthies, H. Mrasek, D. Gohlke, E. Neumann, BAM,.42, D-12200 Berlin
BAM Berlin - NDT Department Lab. VIII
The Federal institute of Materials Research and Testing (BAM) is a scientific-technological institute under the
authority of the Federal Minister of Economics. In accordance with a decree of the Federal Minister of Economins
dates September 1, 1964, BAM promotes the development of german industry by carrying out research on
materials and by further developing testing techniques and chemical safety engineering. The institute collects
and makes the results of its own and others scientific work available to the general public in suitable form.
Director:
Prof. Dr. Wuestenberg
Ultrasonic NDT Department Lab. VIII
D-12200 Berlin
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© Copyright 4. Sept 1996 Rolf Diederichs, info@ndt.net