NDTnet 1998 Aug, Vol.3 No.8

Full-Text - Abstract

Technical ceramics are an important part of the various construction materials in modern machine engineering. It would be advantageous to detect defects or inhomogeniousities in the early process of production to reduce the production costs. The main point of this work is the optimization of different non- destructive testing methods for the testing of green ceramic bodies.
The non-destructive characterization methods, specially the ultrasonic testing, the measurement of the eigenfrequency and the measurement of the Ultrasonic-Contact-lmpedance (UCI), are very interesting for measuring the different material properties fast and with low costs.
The measurement of the eigenfrequency supplies information's about the global elastic reaction of a component. For geometrical defined components the measurement of the eigenfrequencies is a very efficient method to measure the elastic modulus and for the confusion measuring.The problem of the ultrasonic testing is to couple the ultrasonic impulse into the testing material. Because of the destruction of the green ceramic the conventional coupling possibilities with water or other liquids are not applicable. An alternate way can present only by the dry coupling method. In this work, different kinds of ultrasonic dry coupling will be test for their sensitivity and lateral resolution to detect material mismatches. With dry coupling methods it is very difficult to analyse the lateral resolution of a real defect in green ceramic bodies Appropriate devices that allow a water immersion technique for the green ceramic testing will be demonstrate. Another possibility of ultrasonic dry coupling with air-coupled ultrasonic transducers will be suppose.

The UCI-measuring method would be modify for the test of green ceramic bodies. With the aim of a special Indenter it is possible to determine the distribution of the elastic characteristic at the surface or over the cross-section of the green ceramic bodies.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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