Utilização de taninos vegetais como inibidores de corrosão em aço carbono

Abstract

The use of low carbon is very large in the most varied industrial sectors in the world, and its use is very versatile, economical and effective. The major problem in using this type of steel is its susceptibility to corrosion, especially if its use is being used in the media used, which are very frequent in the industry. Therefore, several anti-corrosion methods are used to protect structures and equipment, and an economical and effective method of protection is the use of inhibitors and given the current ecological awareness, using more stringent sustainable legislation, opening up opportunities for research and employment organic, non-toxic inhibitors and renewable sources. It has been reported in the literature that it uses natural polyphenolic compounds extracted from plants, called tannins being used as natural inhibitors of the corrosive process. In this sense, for this study, as corrosion inhibitors for SAE 1020 carbon steel in 0.1 M HCl, tannins extracted from Barbatimão (Stryphnodendron adstringens), tree species from the cerrado biome and cationically modified tannins of black wattle (Acacia mearnsii), using electrochemical methods of potentiodynamic polarization, electrochemical and gravimetric impedance spectroscopy to characterize the inhibition of tannin corrosion, in addition to the use of Fourier transform infrared spectroscopy for product analysis of the reaction between iron and tannin. The results obtained show the mixed inhibitory character for tannins of species as species, achieving good results with 79% inhibition for Barbatimão and 95% for black wattle.