AE Pillay, S Fok, S Stephen and A Abd-Elhameed

Keywords: Metal coatings, interfacial degradation, laser ablation, ICP-MS

Abstract: Degradation of protective coatings on metal surfaces is a common problem, especially in the oil and gas industry, where enormous metal structures have to be shielded. Predicting the extent of coating failure is useful to pre-empt damage to the metal substrate, and save costs. This paper explores the use of laser ablation technology to monitor the level of wear in protective coatings after subjection to severe environmental conditions such as sand blizzards, intense solar irradiation, excessive humidity and rain. Specially coated metal samples were prepared for investigation. Samples were exposed to inclement weather conditions and the level of deterioration to the coating was monitored using the laser ablation technique. The laser penetrated the coating and the time taken to reach the substrate was recorded. If the coating underwent degradation, less time was taken to reach the substrate. Depth profiling in this way made it possible to monitor attenuation of the coating. The laser was part of a high resolution ICP-MS instrument, and irradiations were conducted with a 213-nm beam of 30% total energy and 55 ?m diameter. Prior to each run, the instrument underwent appropriate validation and correction for background interference. Detailed analysis of different spots on the sample also provided information on the evenness of the coating. Investigating coating performance linked to interfacial degradation is relatively novel, and our work would be of considerable interest to research in environmental and materials science.

[View Complete Article]