Effect of Accelerated Ultra Violet Weathering on the Rain Erosion Resistance of Coated Aircraft Transparencies.

摘要

Three proprietary coatings on monolithic polycarbonate transparency material were examined. The coated polycarbonate materials were exposed to one and three years of accelerated ultra violet exposure. The specimens were then exposed at a 30 degrees impact angle to a simulated one inch/hour rainfall at 500 mph in the AFWAL Mach 1.2 Rain Erosion Test Apparatus. Percent coating removal as a function of rainfield exposure was determined. Accelerated UV weathering exposure did not directly affect the coatings' behavior under rainfield exposure conditions but did have an indirect effect on the adhesion of the coatings to the polycarbonate substrate materials. SEM techniques are the most effective in assessing the role of mechanistic processes in rain erosion phenomena.