Rapid nondestructive testing of ceramic multilayer capacitors

A rapid nondestructive test method for ceramic multilayer capacitors made from piezoelectric materials such as barium titanate or lead-containing materials is described and evaluated. The test method is based on the internal excitation of standing acoustic waves in the capacitor. The standing waves are severely dampened by defects such as delaminations and pores. An undampened resonance is a good indication of a defect-free ceramic multilayer capacitor. In addition, a high-speed automated test setup was evaluated that has the potential of the testing of 180000 capacitors per hour with a sorting accuracy of about 92%. In addition, the nondestructive test setup can be integrated with the standard voltage breakdown test, reducing capital investments to a minimum.<
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