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Al-Borno A.,Charter Coating Service 2000 Ltd. | Chen X.,Charter Coating Service 2000 Ltd. | Kewaldas Dhoke S.,Charter Coating Service 2000 Ltd.
International Journal of Corrosion | Year: 2015

Fusion Bond Epoxy (FBE) coating system was exposed to 5% sodium hydroxide at elevated temperature for 30 days. The result of exposure showed formation of adhere deposit layer, a discolored zone underneath and remaining un-affected bulk of the coating. The deterioration of the coating was characterized using analytical techniques like scanning electron microscopy (SEM), energy-dispersive X-ray (EDAX) spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), pull-off adhesion, and electrochemical impedance spectroscopy (EIS). Results obtained indicated chemical deterioration of the coating in the discolored zone and leaching of low molecular weight coating component forming deposit layer. Although the adhesion strength and barrier property were not affected, the polymer matrix in the affected zone undergoes severe changes in its surface microstructure, primary chemical structure, and glass transition temperature. This may inflict serious impairment of the coating functional properties and premature failure of the coating in long term exposure. © 2015 Amal Al-Borno et al.

Melancon M.,Chevron | Hunter P.,Chevron | Hourcade S.,Chevron | Al-Borno A.,Charter Coating Service 2000 Ltd. | And 6 more authors.
NACE - International Corrosion Conference Series | Year: 2014

External coatings used for corrosion protection often have to perform under severely corrosive environments. One major concern regarding coating performance is the negative effect of soluble salts on the steel substrate at the time of coating application, particularly for marine maintenance coating applications. These salts impact the ability of the applied coating systems to protect the steel in several ways including osmotic coating blistering, promotion of under-film metallic corrosion and coating disbondment. This paper focuses on removal of soluble salts contamination by commercially available decontamination processes in relation to external coating systems. We directly compare the effectiveness of four cleaning methods with the performance of ten coating systems. The methodology of surface contamination and preparation of test panels is discussed. After cleaning, sample evaluation for chloride ion contamination levels was carried out using Field method (commercial chloride ion test kit for surfaces) and Ion Chromatography method. Additionally, Scanning Electron Microscopy / Energy Dispersive X-ray Spectroscopy (SEM/EDX) and elemental surface mapping analysis were carried out. Laboratory testing of coating systems included Adhesion, Porosity, Electrochemical Impedance Spectroscopy (EIS) analysis and cyclic UV/Salt Fog exposure.The performance of the ten coatings on all the substrates was good, but there were differences in gloss retention and on the degree of checking of the different coatings. The only significant difference in performance of the coatings compared to the method used for cleaning the substrate was higher undercreep observed for most of the coatings applied to the ultra-high pressure water jetted system. This shows the importance of substrate preparation due to the sensitivity of the coatings to even low levels of salt. Two coatings did not show increased undercreep and these may be more applicable for offshore maintenance applications where dry abrasive blasting is sometimes not used. The chemical treatment cleaning method used prior to coating application did not show any significant positive or negative effect on the performance of the applied coatings. The fact that the only differences in performance for the coatings applied to the differently prepared substrates was seen for undercreep suggests that the difference may be exacerbated for immersion situations. A follow up study to this one will examine the performance of internal coatings using immersion tests, and it will be interesting to see if these show increased effect on coating performance. ©2014 by NACE International.

Al-Borno A.,Charter Coating Service 2000 Ltd. | Brown M.,Charter Coating Service 2000 Ltd. | Rao S.,Charter Coating Service 2000 Ltd.
NACE - International Corrosion Conference Series | Year: 2010

Current test standards for Cathodic Disbondment (CD) tests do not include tests that are close to or above 100°C; primarily because of difficulties associated with evaporation of the electrolyte in such tests and because there has been little demand for such high temperatures. However, with the increasing use of pipelines and other vessels at temperatures above 100°C, the need for preferably standardized tests that will evaluate coatings at these higher temperatures has become something that needs urgent attention. Many currently used CD test standards employ methods that have both pipe sample and testing electrolyte at the same temperature but these tests have not been viable for test temperatures above 80°C - 90°C because of electrolyte evaporation. This paper describes the development and testing of a high temperature test apparatus that allows for CD testing in a pressurized test vessel. The vessel allows testing at high temperatures of electrolyte as well as standard potential measurements and control. It also provides methods for controlling oxygen concentration in the electrolyte. Comparative data from tests using the new apparatus and other test methods are included that demonstrate the influence of changes in temperature, pressure, and oxygen content in the test electrolyte. Further to this work, another CD test cell was designed, built and tested which incorporates a cooling jacket on the cell such that high temperature CD tests can be run at ambient pressure conditions. This paper includes discussion of the affects of oxygen concentration levels, electrolyte temperatures, and the merits of the different CD test methods. © 2010 by NACE International.

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