Proposal for evaluation of new flaws in paintings Pin-Holes and the quantification of the total flaw of a system

摘要

The development of new paintings and the climatic changes makes that mew forms of deterioration shows up in coatings of frequently use in protection of structures exposed to the environment, in atmospheres of high radiation and high evaporation as a semi-arid regions in Venezuela. The studies about painting systems with good mechanical properties are necessary to be done. Also chemical resistance against the corrosion is necessary, where the uniformity of the film guarantees a protection at least to medium term too. Coatings elaborated with epoxy - resins have good properties like protection system, but they usually come with a high load of pigmentation with the purpose from increasing the coating power and the thickness of the film to be formed once evaporated the solvent. The numerous appearance of the small caverns (that don't leave to the discovered metal) that are know as "pin - holes" they still appear before the tests of elements. Methodologies to evaluate these flaws have been proposed in this study, likewise it intends to set an equation to convert results of qualitative evaluations normalized in quantitative results in way of being able to compare systems of paintings globally. Evaluations were made in a semi-arid marine-tropical atmosphere where the epoxy-poliamide coating rehearsed presented the new flaw before the beginning of the rehearsal, becoming a similar flaw finally to a bladder exploded initiate by of a visible corrosion after six months of exhibition.