Hoar frost accretion on organic coatings under offshore conditions

Nine organic corrosion protection coating systems are investigated according to their hoar frost accretion performance under simulated offshore conditions. A special test scenario is developed for the generation and measurement of defined hoar frost layers. Hoar frost layer thickness is estimated on newly applied coatings and on artificially aged coatings. The aging procedure refers to offshore conditions, which mainly cover low temperatures, dry-wet cycles, salt spray, and ultraviolet (UV) radiation. In average, the accreted thickness either did not change significantly or increased. Spearman's rank correlations were estimated for all surface parameters. If all measurements (new and aged) for an individual surface parameter were considered, only weak correlations were found between hoar frost thickness, static contact angle, specific surface energy, and surface roughness. The importance of UV radiation on the appearance of hoar frost is highlighted.