Effect of pore sealer in the behavior of thermal sprayed aluminum and zinc coatings in marine and coastal marine atmospheres

• Orlando Salas Universidad del Zulia-Venezuela
• ílvaro Rincón Universidad del Zulia-Venezuela
• Oladis de Rincón Universidad del Zulia-Venezuela
• Miguel Sánchez Universidad del Zulia-Venezuela
• Luis Maldonado Universidad del Zulia-Venezuela

Palabras clave: aluminum thermal sprayed, zinc thermal sprayed, atmospheric corrosion, marine atmospheres, accelerated tests

Resumen

The objective of this research is to study the effect that have pore sealers in the behavior of Thermal Sprayed Cinc y Aluminum, and Zn/Al coatings in marine and coastal marine atmospheres, during one year of exposition. To that effect, carbon steel sheets (10cm x 15cm x 3mm) were sprayed by using two different processes (electric arch and flame spray), with and without the application of two additional layers of sealer. Three sealers were evaluated: two wash primers of different suppliers, and a phenolic sealer. The sheets were exposed in two atmospheric test sites, La Voz (coastal marine atmosphere), and the Towers of the crossing of the Lake of Maracaibo (marine atmosphere). The sheets were characterized by means of initial weight, thickness, metallographic, adhesion, roughness, being evaluated monthly by visual inspection and photographic. The results showed that in these aggressive atmospheres, where the wind effect is important, the thermal sprayed Zn/Al coating, offers an excellent behavior even without sealer, producing galvanic protection to the substrate. In the case of thermal sprayed of Cinc and Aluminum coatings, a phenolic based pore sealer should be used, for covering completely the irregularities owned by this type of coating.