Abstract:
In order to guarantee the quality of ceramic products, about two order smaller sizes of defects in fine ceramics should be detected compared to metallic materials. In order to attain high sensitivity of detection in ultrasonic test, focusing typed transducers are used in water-immersion method. The frequency of the ultrasonic is much higher being ranged between 15 to 100 MHz. The attenuation of ultrasonic in ceramics is large and depends very strongly on porosity of the specimens. The selections of the characteristics of transducers and testing conditions are very important. For the speedy and reliable testing, the trial tests using reference test pieces are very important. In this report, the characteristics of ultrasonic testing of fine ceramics are presented with using some types of reference test pieces newly fabricated from silicon nitride ceramics. For surface flaws and inner flaws, some kinds of test pieces are fabricated and the echo-heights are examined with the sizes of defects, which sizes are ranged from 30 to 500 µm. Quantitative relationships have been obtained between them.
(Ref. SXVIII-022-97)
Source: NDE of Ceramics '97 May 4-7, Symposium on Nondestructive Evaluation of Ceramics
at the American Ceramic Society 99th Annual Meeting, Cincinnati, Ohio.
Buying the Symposium Proceedings from the American Ceramic Society.
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