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Proceedings Paper

Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging
Author(s): Sanjay Ahuja; William A. Ellingson; J. B. Stuckey; E. R. Koehl
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Paper Abstract

Ceramic matrix composites are being developed for numerous high temperature applications, including rotors and combustors for advanced turbine engines, heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon-carbide-fiber- reinforced-silicon-carbide (SiC(f)/SiC), silicon-carbide-fiber-reinforced-silicon-nitride (SiC(f)/Si3N4), aluminum-oxide-reinforced-alumina (Al2O3(f)/Al2O3, etc. In the manufacturing of these ceramic composites, the conditions of the fiber/matrix interface are critical to the mechanical and thermal behavior of the component. Defects such as delaminations and non-uniform porosity can directly affect the performance. A nondestructive evaluation (NDE) method, developed at Argonne National Laboratory has proved beneficial in analyzing as-processed conditions and defect detection created during manufacturing. This NDE method uses infrared thermal imaging for full-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Nonuniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares-estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fiber coating in a full array of test specimens.

Paper Details

Date Published: 15 March 1996
PDF: 9 pages
Proc. SPIE 2766, Thermosense XVIII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications, (15 March 1996); doi: 10.1117/12.235382
Show Author Affiliations
Sanjay Ahuja, Argonne National Lab. (United States)
William A. Ellingson, Argonne National Lab. (United States)
J. B. Stuckey, Argonne National Lab. (United States)
E. R. Koehl, Argonne National Lab. (United States)

Published in SPIE Proceedings Vol. 2766:
Thermosense XVIII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications
Douglas D. Burleigh; Jane W. Maclachlan Spicer, Editor(s)

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