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Comparison between piezoelectric method and ultrasonic signal analysis for crack detection in type II multilayer ceramic capacitors
Author(s) -
Ousten Y.,
Mejdi S.,
Bechou L.,
Tregon B.,
Danto Y.
Publication year - 1998
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/(sici)1099-1638(199803/04)14:2<91::aid-qre167>3.0.co;2-7
Subject(s) - piezoelectricity , short time fourier transform , ultrasonic sensor , materials science , acoustics , ceramic capacitor , pmut , signal (programming language) , transducer , electrical impedance , signal processing , capacitor , fourier transform , electronic engineering , computer science , electrical engineering , engineering , digital signal processing , fourier analysis , composite material , voltage , mathematics , physics , mathematical analysis , programming language
In this paper we present a comparison between two non‐destructive techniques for crack detection in MLCCs. First, if a type II MLCC is biased with a DC field, the capacitor becomes temporarily ‘poled’ and can act as a transducer. This is induced by a residual piezoelectric effect used in the impedance spectroscopy method. Second, we used a scanning ultrasonic system working in the 10–100 MHz frequency bandwidth. To understand the ultrasonic signature, we used time‐of‐flight (TOF) detection with short‐time Fourier transform (STFT) analysis to determine the depth and nature of defects with high accuracy. An application of digital signal processing to the characterization of defects is presented for a lot of MLCCs with cracks defects. For comparison, the same lot was tested with the piezoelectric method. The two techniques are closely correlated. © 1998 John Wiley & Sons, Ltd.