Accelerated Test Research Of Coating Protection System Failure In The Simulated Desert Environment

Coating protection system is easy to fail early in various corrosive environments, so choosing the excellent coating protection system is extremely critical. The desert environment has become a kind of special corrosion environment. Gloss loss, powder, crack and spall always appear in the coating which causing the damage of equipment and resulting in safety accident. Therefore, choosing suitable coating protection system is important.This experiment adopted new cyclic environment factor experimental methods which were UV exposure and blowing experiment to test aging behavior of high solid coating,13-2 coating and TS96-71 coating of the substrate in titanium alloy, aluminum alloy, steel, of surface treatment in ion aluminizing, sulfuric acid anodizing, passivation, a total of 42 kinds of coating protection system in the desert environment in 8 years. The failure process of coating system was showed through the weight (thickness) loss, the gloss loss, surface morphology and electrochemical methods. The failure result of coating system was showed by the micro morphology and adhesion rank. In order to evaluate coating protection system, we created a new mathematical method. The degree of base and surface treatment and coating on the performance impact of protective coating system was analyzed by the results. Analysis of coating failure mechanism was gotten by EDS and infrared spectroscopy and scanning electron microscopy, and the relationship between mechanical properties and coating grade was analyzed through nano indentation method.The experimental results showed that:the conventional parameters of coating had some change laws. Changes in macroscopic surface morphology showed the coatings’breakage occurred locally then uniform corrosion. Electrochemical behavior showed the process of falling of the coating performance. The formula of protective performance of coating was calculated by AHP and reliability of the evaluation was verified with electrochemical method. It turned out that the substrate and surface treatment is negligible in affecting the system performance of the protective coating, but the coating, and 13-2 coating system was best, TS96-71was better and high solid coating was good. Failure mechanism was gotten through the analysis of infrared spectrum and the microstructure of coating:UV radiation broke chemical bond of coating. Sands erosion produced impact crater and cracks which leaded to the continuous loss of coating material. Based on the three kinds of coating parameters of mechanical properties (elastic modulus and hardness) comparing with coating volume erosion rate and aging rating results, we founded that the coatings’hardness H and elastic modulus E were bigger, the more serious the volume erosion and the degree of aging.