|Here are some places to look for more information.
The standard technique with thermography is that the coating is flash heated and then viewed with an infra red camera. "Hot spots" indicate areas of poor bonding or greater coating thickness.
Degradation of Powder Epoxy Coated Panels Immersed in a Saturated Calcium Hydroxide Solution Containing Sodium Chloride. Final Report. August 1992-July 1994. See http://www.fire.nist.gov/bf...
Paper #: 2114-27
Damage to coated ZnSe optical components by high-power CO2 laser
Abstract: Coated ZnSe optical components are irradiated with
high-power, pulsed CO$-2$ laser radiation ($lambda $EQ
10.6 $mu@m, pulse length approximately 100 ns) at
fluences up to 210 J/cm$+2$/. The components are
characterized at various stages of irradiation by
thermography, optical microscopy, stylus profilometry,
and surface chemical analysis (x-ray photoemission and
Auger electron spectroscopy). During irradiation no
temperature in the component surface is observed. Two
types of coating damage occur within the irradiated
area of the component: a breaking apart of the ZnSe
overlayer of the coating system over relatively large
areas, and the formation of isolate craters of diameter
approximately 30 - 50 $mu@m extending in depth
approximately 3 $mu@m through the coating system down
to the ZnSe substrate. Chemically, the irradiated area
is characterized by an oxidation of both Zn and Se and
an increase in the stoichiometric ratio of Zn to Se.
These effects are especially pronounced at the crater
defects, and are attributed to localized optical
absorption, leading to thermal stress and chemical
reactions of Zn and Se with atmospheric or adsorbed
water and/or oxygen.!11 See http://www.spie.org/web/abs...
Editor(s): George S. Baird, Baird Infrared Technology, Inc., Berlin, NJ, USA.
ISBN: 0-8194-0576-0, 488 pages. Published 1991
Meeting Date: 04/01/91, Orlando, FL, USA
A Thermographic Method to Determine Coating Thickness on a Metallic Substrate
A quantitative thermographic NDE technique for the characterization of impact damage in composite materials is under development along with supporting theoretical analysis. We have previously shown that the technique of time-resolved infrared radiometry (TRIR) is an effective method for quantitatively detecting coating thickness variations and for characterizing the degree of coating disbonding in terms of equivalent air gaps. See http://www.cnde.iastate.edu...
Application of Infrared and Visual Imaging for Inspection and Evaluation of Protective Coatings See http://www.iti.nwu.edu/pubs...
We are studying potential applications for emissivity-corrected thermal NDE to:
Measure coating thickness variations
Measure interior pipe corrosion loss
Monitor dynamics of polymer cure states
Evaluate heat transfer in laser welding processes
Many of the papers that have been presented at Thermosense over the past 20
years are now available on a CD-rom. The 400+ papers that are included are searchable PDF format and have all images as they are in the original publications. You can order from SPIE
(www.spie.org) for $110. This is an incredible resource for all thermographers!