High-Build, Direct-to-Metal Atmospheric Coatings for Moderately Corrosive Environments

摘要

Direct-to-metal (DTM) coatings are used in mildly corrosive environments (C3 per ISO 12944-2) because their ease of use and single-coat application offers throughput advantages over multi-coat systems. DTM coatings consist of a number of different resin chemistries that allow for high-film build including epoxies, polyurethanes, polyaspartics and polysiloxanes. Each coating type has a unique combination of cost, application characteristics and performance properties. This study compares application characteristics and physical properties of these coatings when applied to NACE No. 2/SSPC SP-10 blasted steel panels. The following ASTM tests were used to characterize each technology: salt fog, abrasion resistance, flexibility, impact resistance, dry-time, pull-off adhesion, and accelerated weathering. The majority of the coatings passed the C3-high requirements of ISO 12944-6. The qualities that differentiate coating technologies are ease-of-application, corrosion resistance, dry-time, flexibility, and weatherability.