The research work performed on 12 coil coating materials in the frame of the PATINA Network (Anticorrosive Protection in the Atmosphere) sponsored by CYYTED is discussed. It includs the task accomplished by Science and Technology institutions of Ibero-America on formulations supplied by different prcoduction Sector companies from the participating countries, between 1996 and 2000. Coil coating schemes were exposed outdoors, according to ISO 2810 standards, in 9 ambient conditions of the MICAT (Ibero-American Test Stations Network), CYTED. The protective characteristics on the steel base metal was determined as a function of time, following ISO 4628 and ASTM D 3274 standards. Electrochemical impedance spectroscopy (EIS) was applied on various materials after 1, 2, 3 years and 42 months exposure, to evaluate the weathering effect in different atmospheric conditions.

This article presents the results obtained at 16 tropical test sites participating in the “Ibero-American Map of Atmospheric Corrosiveness” (MICAT), a project on atmospheric corrosion carried out during the period 1988–1994 at some 70 test sites distributed across 12 countries of the Latin-American region, Spain and Portugal. The tropical climate and its different climatic variants are characterized by high average air temperatures, with considerable daily thermal fluctuations, high average relative humidity, and generally high precipitation volumes. The work is structured in three main blocks: apparently unpolluted atmospheres (i), and marine atmospheres, differentiating between pure marine atmospheres (ii) and those in which both chloride (Cl-) and sulfur dioxide (SO2) pollutants coexist (iii). In each block an attempt was made to determine the role of the tropical climate in the magnitude of corrosion attack shown by four typical reference metals (mild steel, zinc, copper and aluminum) exposed for one-year periods in tropical atmospheric exposure conditions.

Aluminium generally presents good corrosion resistance to the atmosphere. However, unprotected aluminium and aluminium alloys weather outdoors to an ugly grey colour, which deepens to black in industrial atmospheres, and undergo superficial pitting in marine atmospheres, etc. Finishing technologies are applied for their protection and decoration in a wide range of applications. These technologies basically consist of two protection processes: anodizing and painting; the latter going from conventional solvent base paints to modem water-borne, high solids and powder coatings. This paper considers the weathering performance of three paint systems: alkyd, polyurethane and polyester, after more than three years of exposure in a wide spectra of Ibero-American atmospheric conditions. The information reported includes resistance to undercutting corrosion at the scribe, filiform corrosion, fungal attack and change in the physical-chemical properties of the paint surface (loss of gloss, colour changes, chalking, etc.). KeywordsAtmospheric behaviour. Aluminium. Painting. Lackering. Ibero-America. Comportamiento del aluminio pintado en las atmósferas de IberoaméricaResumen El aluminio, en general, presenta una buena resistencia a la corrosión en la atmósfera. Sin embargo, el aluminio sin ninguna protección y las aleaciones de aluminio expuestas a la intemperie envejecen mostrando un color gris, negro en el caso de atmósferas industriales, sufren la formación de picaduras en atmósferas marinas, etc. Para su protección, o a efectos decorativos, se le aplican diferentes procesos de acabado en un amplio rango de aplicaciones. Estos procesos de acabado, básicamente consisten en dos métodos de protección: anodizado y pintado; este último abarca desde pinturas convencionales de base disolvente hasta modernos sistemas base agua, de alto contenido en sólidos o pinturas en polvo. Este trabajo considera el comportamiento de tres sistemas de pinturas: alquídico, poliuretano y poliéster, tras más de tres años de exposición en un amplio espectro de condiciones atmosféricas de Iberoamérica. La información presentada incluye la resistencia a la deslaminación en la incisión, corrosión filiforme, ataque por hongos y cambios en las propiedades físico-químicas de la superficie de la pintura (pérdida de brillo, color, entizado, etc.) Palabras claveComportamiento en la atmósfera. Aluminio. Pintado. Lacado. Iberoamérica

Accelerated laboratory tests on 12 materials in study in the Subgroup 6 of the PATINA Network (CYTED), are discused for different exposition periods in salt spray, SOj and Prohesion chambers. International standards used to evaluate failures caused by the different aggressive agents of these laboratory tests are the same as those applied for outdoor expositions. The results exposed contribute to a better understanding of the mechanisms occurred in the diverse natural environments, being mentioned the main analogies and differences respect to factors affecting natural tests.They also allowed to evidence the advantages and limitations in the application of these tests during several days, as compared to the years required to attain similar failure magnitudes through outdoor tests. Ensayos acelerados de recubrimientos para banda continua ResumenEn este trabajo se discuten los ensayos de laboratorio acelerados, realizados sobre 12 materiales de estudio en el Subgrupo 6 de la Red PATINA (CYTED), a diferentes periodos de exposición en cámaras de niebla salina, SOj y Prohesion. Se utilizaron las normas internacionales para evaluar los fallos causados por los diferentes agentes agresivos de estos ensayos de laboratorio, las cuales se aplican también para los ensayos de exposición a la intemperie. Los resultados expuestos contribuyen a una mejor comprensión de los mecanismos ocurridos en los diversos ambientes naturales, mencionándose las principales analogías y diferencias respecto de los factores que afectan los ensayos naturales. También permitieron evidenciar las ventajas y limitaciones en la aplicación de estos ensayos durante varios días, en comparación con los años requeridos para alcanzar magnitudes de fallos similares por medio de ensayos a intemperie.Palabras clave Ensayos acelerados. Ensayos normalizados. Recubrimiento para banda continua.

This paper summarizes the experience developed during various research work performed using 2024-T3, 7075-T6, and 7005-T6 aeronautical aluminum alloys in different natural and laboratory aqueous media. The effect on corrosion of the components of a mineral aqueous nutrient medium that supports fungus proliferation was evaluated using an electrochemical technique. Through anodic and cathodic potentiokinetic polarizations, it was possible to determine the susceptibility, type, and relative amount of corrosion damage to the alloys in the medium as well as changes in the medium caused by the metabolic consumption of its components. The microbiological-influenced corrosion (MIC) effects associated with metallurgical characteristics of the alloys, such as the thermomechanical treatments, secondary phases, and surface roughness, were also determined by means of the polarization tests. These tests are very useful accelerated techniques to evaluate the susceptibility of an aluminum alloy to localized attack in a given environment. They also provide information concerning the morphology and magnitude of the damage.