Measurement of coating physical properties and detection of coating disbonds by time-resolved infrared radiometry

• Published in: Journal of nondestructive evaluation Vol. 8; no. 2; pp. 107 - 120
• Main Authors: Maclachlan Spicer, J. W., Kerns, W. D., Aamodt, L. C., Murphy, J. C.
• Format: Journal Article
• Language: English
• Published: 01-06-1989
• Subjects: bonding; inspection; nondestructive testing; physical properties
• ISSN: 0195-9298; 1573-4862
• DOI: 10.1007/bf00565635

The principles and applications are described of time-resolved infrared radiometric (TRIR) imaging to characterization of coating systems. Examples are given of its application to the measurement of coating properties such as thickness and thermal diffusivity and to the detection of regions of coating disbond. Results are shown for coatings of different thickness, for test specimens (e.g. Al 6061) containing artificial disbonds, and for thermal barrier coating specimens exhibiting real disbonds. A theoretical model describing the time development of the surface temperature of a coating during step heating is presented and the experimental results show good agreement with this model. Methods of applying the technique for inspection of large areas of coating, as would be required in a process control or in service inspection environment, are discussed and examples of parallel data acquistion using line heating sources are presented. Graphs. 14 ref.--AA(US).