Critical Assessment of the Integrity of Thin Organic Films by Shearography |
| |
Authors: | K Habib |
| |
Affiliation: | (1) Materials Science Laboratory, Department of Advanced Systems, KISR, P. O. Box 24885, Safat, 13109, Kuwait |
| |
Abstract: | The temperature versus thermal deformation (strain) with respect to time, of different coating films was studied by a non-destructive
technique (NDT) known as shearography. The behavior of organic coatings, i.e., epoxy, a white enamel, or a yellow acrylic
lacquer on carbon steels, was investigated at a temperature range simulating the severe weather temperatures in Kuwait especially
20–60 °C differences between the daylight and the night time temperatures. The investigation focused on determining the in-plane
displacement of the coatings, which amounts to the thermal deformation that results from the applied temperature range. Furthermore,
the investigation also focused on determining the thermal expansion coefficients of coatings and the slope of the plot of
the thermal deformation versus the applied temperature range. A critical (steady state) value of the thermal expansion coefficients
of coatings was used to determine the integrity of the coatings with respect to time. This value was determined from the decreasing,
time-dependent value of the thermal expansion coefficients of coatings. In fact, determination of critical (steady state)
value of the thermal expansion coefficients of coatings could be accomplished independent of parameters such as UV exposure,
humidity, presence of chemical species, and other parameters normally considered in conventional methods of the assessing
of the integrity of coatings. By using the technique of shearography, one needs only to determine the critical (steady state)
value of the thermal expansion coefficients of coatings, regardless of the history of the coating, in order to assess the
integrity of coatings. These results indicate that the technique is a very useful NDT method for determining the critical
value of the thermal expansion coefficients of different coatings and can be used as a 2D-microscope for monitoring the deformation
of the coatings in real-time at a submicroscopic scale. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|