Acoustic Emission in Solids

conference paper

English

A tested tile with metal electrodes on sides creates a parallel plate capacitor. This metal-insulator-metal system has electrical characteristics represented in low electric field by constant value of conductivity and permittivity. The measured V-A characteristic of a glazed tile with thickness of 9.6 mm revealed that this characteristic is linear up to about 2.5 kV. At this voltage partial discharges are created and V-A is becoming to be quadratic function of applied electrical field. The partial discharges have an impact on conductivity and they are important sources of acoustic emission signals. To decrease the influence of bubbles located between the metal electrode and ceramic we have applied graphite paint on the surface of tile. The partial discharges are related to ceramic density and sample homogeneity. Cracks are significant source of partial discharges and acoustic emission signals. This quantity was used for technology assessment and quality testing. Applying of a step voltage on M-I-M structure creates polarisation current, which is a result of slow polarisation phenomena. A relaxation time of this polarisation depends on applied electric field and is strongly related to the appearance of the partial discharges. The experimental investigation of acoustic and electromagnetic emission signals can be used to localise the crack position.

Acoustic emission, Partial Discharges, Non-destructive Testing, Ceramic Tiles

PAVELKA, J., KOKTAVÝ, P., NAVAROVÁ, H.

2002

1. 1. 2002

Ing. Zdeněk Novotný, CSc., Ondráčkova 105, Brno

Brno

80-238-9094-8

Noise and Non-linearity Testing of Modern Electronic Components

1.

145

296

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