Contaminação superficial do aço-carbono zincado por imersão a quente cromatizado não-cromatizado com ions cloreto

Abstract:

The presence of soluble salts in the interface metal / ink has been the cause of many cases of failures coating systems. In the case of carbon steel painted, many studies have been conducted to establish maximum levels of acceptable contamination. Although there is still no consensus, are found in the literature, values ​​ranging from 3 to 50 μg/cm2 μg/cm2 depending on exposure conditions. As for zinc, studies aimed at determining acceptable levels of contamination are rare, although there are several references stating that the presence of soluble salts is detrimental to adhesion of inks, with many cases of premature failure of galvanized steel, hot dip painted. In this paper, galvanized steel sheets were hot-dip ranging industrial conditions to obtain surfaces with different degrees of contamination. These sheets were then painted without removal of surface contamination and subjected to accelerated tests and non-accelerated corrosion in an attempt to correlate the level of contamination of performance. Immersion tests in distilled water were also conducted and evolution of the interface behavior metal / ink was monitored both by traditional electrochemical measurements as per Kelvin probe. The results showed that even low levels of contamination undermine the performance of paints and which is not controlling the process of hot-dip galvanizing that reach satisfactory practical results as regards Paint galvanized steel, hot dipped, should be direct efforts to make appropriate pretreatments.


Reference:
PANOSSIAN, Z.; BRAGAGNOLO, G.M; FERRARI, J.V; FRAGATA, F.L; ANDREOLI, M.C; ALMEIDA, M.B; ALMEIDA, N.L Contaminação superficial do aço-carbono zincado por imersão a quente cromatizado não-cromatizado com íons cloreto. In: CONGRESSO BRASILEIRO DE CORROSÃO, INTERCORR, 28., 2008, Recife. Anais…

Access to the article on the ABRACO website:
https://abraco.org.br/src/uploads/intercorr/2008/INTERCORR2008_069.pdf



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