Volume No. 3 Issue No.: 2 Page No.: 353-361 Oct-Dec 2008

 

ASSESSMENT OF ENVIRONMENTAL DEGRADATION OF METAL-COATINGS USING LASER-ABLATION TECHNOLOGY (ICP-MS)

 

A.E. Pillay*, S. Stephen, A. Abd-Elhameed1 and S. Fok2

1. Department of Chemistry, The Petrolium Institute, PO Box 2533, Abu Dhabi (UAE)
2. Department of Chemical Engineering, The Petroleum Institute, PO Box 2533, Abu Dhabi, (UAE)

 

Received on : August 18, 2008

 

ABSTRACT

 

Predicting the extent of coating wear-and-tear on metal structures is significant in the oil and gas industry, as equipment failure can seriously hinder the operation and profitability. Coatings and sealers are commonly used for stability and protection against degradation in materials. To assist degradation monitoring and control, coating performance must be accurately evaluated. Many approaches are available for the measurement of coating performance, but each of these has its inherent advantages and drawbacks. However, none of these techniques is able to characterize the coating as well as the material it is protecting. This work investigates the use of laser ablation technology, not only to characterize the coatings and materials, but also to evaluate the level of wear in protective coatings following inclement environmental conditions such as intense solar irradiation, excessive humidity and sand blizzards. Specially coated metal samples were prepared for investigation. Samples were exposed to stringent weather conditions and the level of damage to the coating was evaluated using the laser ablation technique. The penetration of the laser through the protective coating across a sample surface was used to determine the quality of the coating over an area. If the coating was completely worn away at certain points, the approach detects the varying composition of the substrate. Any serious physical or chemical change in the coating composition due to solar energy, thermal conditions or chemical abrasion from acid rain (for example) is expected to alter the penetration depth - compared to a control sample subject to identical irradiation conditions. This is automatically reflected as a dramatic change in the accumulated spectra. As a result, change in stability due to environmental exposure could be predicted. The laser itself is attached to a high resolution ICP-MS instrument, and irradiations were conducted with a 213-nm beam of 30% total energy and 55

 

Keywords : Surface coatings, Lases-ablation technology, Degradation, Environmental conditions.

 

 

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