zincofix durability
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DURABILITY OF THE LAMINAR ZINC COATING ZINCOFIX® A case of a Zincofix®coating applied in the year 1991 Zinc Laminate Coating technology in the corrosion protection of steel structures exposed to the atmosphere has been used since the 1980’s. The system consists of a pure zinc foil with an electro-conductive adhesive that is cold-applied to steel structures. In addition to the natural passivity protection of the zinc coating, the electro-conductive adhesive also provides active protection, giving the structure greater durability. The zinc foil used for Zinc Laminate Coating is known on the market as Zincofix®. A typical case of the durability of the Zincofix® coating is represented by a series of applications carried out for an important client on pipes of different diameters in the year 1991 (approx. 8000 m2). In view of the excellent results over the previous 30 years, the client, as part of a restructuring plan, planned new similar interventions on pipelines, and has requested an inspection of the state of the coating applied 31 years ago. INSPECTION ON COATING APPLIED IN 1991 The inspection was carried out according to the UNI 10781 standard. In practice, samples of the tape (approx. 50mm x 100mm) were taken on various structures and the adhesive strength was checked, as well as the condition of the substrate and the residual thickness of the zinc. The samples taken were sent to an independent laboratory for further technical analysis. The sampling areas were sealed with a patch of new tape, which will oxidize over time to the same color as the preexisting coating. This is one of the great advantages of the product that allows partial repairs on any artefact LABORATORY ANALYSIS FOR RESIDUAL THICKNESS VERIFICATION The analysis report shows that the original Metalnastri foil had a thickness of 85/90 microns and a chemical composition made of pure zinc 99.99%. It is likely that the applications performed on the pipelines around the end of the 1980s were also made with zinc foil of similar characteristi

The detail of the laboratory certificate shows that: - The average of about 10 foil samples taken on structures inside artefacts and exposed to high humidity was about 85 microns thick. In some cases, the thickness was even greater than the initial thickness, due to the thickness of oxide caused by zinc passivation. - The average of about 10 foil samples taken on structures outside the artefacts, and thus exposed directly to the atmosphere, was about 70 microns in residual thickness. Laboratory results have shown that the residual zinc thickness still has a very good state of preservation...