| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inspecting a piezoelectric ceramic element, capable of detecting the internal flaw in the piezoelectric ceramic element, which can not be detected by the temperature rise due to heating from the outside, in a non-destructive manner. SOLUTION: A high frequency measuring signal having a level higher than the rated level of the piezoelectric ceramic element is applied to the piezoelectric ceramic element and at least one of the phase characteristics and impedance characteristics of the piezoelectric ceramic element accompanied by the application of the high frequency measuring signal is measured. This measured value is compared with characteristics becoming a standard and the presence of the flaw in the piezoelectric ceramic element is detected from the comparing result. The piezoelectric ceramic element is strongly excited by the application of the high frequency measuring signal and generates heat itself by dielectric heating and the internal flaw of the piezoelectric ceramic element can be certainly detected.
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