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Development of New Multifunctional Coatings for Protection Against Erosion and Corrosion in Qatar Oil and Gas Production
Coatings can provide low-cost protection against corrosion and erosion in pipelines and vessels. Points where fluids impinge on surfaces, such as pipe bends and separator walls, are particularly vulnerable. Application of coatings in such instances is particularly promising because the protective vehicle can be applied over low-cost alloys, proving economical solutions to materials problems.
Recently multiphase coatings have been examined for a wide variety of applications. Such coatings consist of a polymer matrix containing hard, abrasion-resistant ceramic particles. Several ceramics are used to impart erosion resistance. Typically, aluminum oxide or titanium dioxide are used because they have desired physical properties, and the cost of these materials is relatively low.
The present investigation focuses on electrochemical evaluation of protective properties of a set of multiphase coatings in the environment encountered inside of off-shore natural gas pipelines. The coatings ranged in thickness and amount of abrasion-resistant ceramic filler (listed in Table 1).
Coating Powder-phenolic novolac |
|
Filler Amount |
Thickness |
1.3 X |
4.5-12 mils |
X |
4.5-14 mils |
0.125X |
4.5-14 mils |
The coated panels were immersed in a solution of 2000 ppm Cl-, pH 3.5,saturated with CO2, at temperature 60C . The electrochemical impedance spectra were collected as a function of immersion time. In addition, the effect of erosion on corrosion performance of the coatings is being tested according to ASTM D968 standard. For these erosion corrosion tests the coatings are periodically removed from the testing solution, subjected to abrasive action of falling SiC particles and then immediately immersed back in the solution.
The EIS data of coatings prior to any erosion indicates that the corrosion performance is independent on amount of filler used; however, the thicker coatings showed the best corrosion resistance. EIS of specimens exposed to periodic erosion is still underway and these results will be presented.