Ceramic joint interface diagnostics with ultrasonic reflection signal energies
The properties of silicon nitride ceramic joints, prepared by hot isostatic pressing, have been investigated by recording the reflected ultrasonic elastic wave off the joint interface. Experimental and theoretical analysis of the reflected signal energy has shown that properties of the joint interface such as thickness, joining compound composition, inclusions, and voids, can be imaged over the joint plane. A model incorporating plane waves shows that the reflected signal energy is a function of joint thickness, joint/host acoustic impedence and transducer bandwidth. For joint thicknesses less than the average ultrasonic wavelength in the joint, the reflected signal energy depends quadratically on the thickness. This dependence was verified by for several joints by direct measurement. In the opposite regime, where the joint thickness is greater than the ultrasonic wavelength, the reflected signal energy is independent of thickness and only a function of the joint/host acoustic impedence mismatch. This regime was not accessible with the bandwidth transducers. The results suggest that for a given range of thicknesses, measurement of the joint energy with broadband transducers with different center frequencies could provide a means of determining both the joint thickness and joint/host acoustic impedence mismatch. Joint thickness is the most prominent parameter that can be probed with ultrasonics and its effect on fracture toughness should be an important parameter in determining the quality of joints. Qualitatively, the reflected signal energy method of data analysis is a rapid means for assessing joint quality with respect to thickness, inclusions, and voids.
- Research Organization:
- EG and G Idaho, Inc., Idaho Falls, ID (USA)
- Sponsoring Organization:
- DOE/NE
- DOE Contract Number:
- AC07-76ID01570
- OSTI ID:
- 6387462
- Report Number(s):
- EGG-SCM-8069; ON: DE91001826
- Country of Publication:
- United States
- Language:
- English
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