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Detection of Coating Problems IR Newbie 9/5/2000
Does anybody have any examples of detection of poor coating quality (painting)with IR thermography?
 
RE:Detection of Coating Problems Gary Orlove 9/6/2000
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
radiation, pp.732-739
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...


Thermosense XIII
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
See http://www.spie.org/web/abs...

A Thermographic Method to Determine Coating Thickness on a Metallic Substrate
See http://www.num.uni-sb.de/o/...

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
See http://www.llnl.gov/IPandC/...

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!
 
RE:Detection of Coating Problems donny 11/18/2000
hi Gary
i have more data about poor coating quality(painting) if you want any examples please send email to me gustian@usanetmail.com perhaps i can help you
 


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