Avaliação de aditivos Nanocompositos para tintas anticorrosivas a base de Epoxi

Abstract

Carbon steel A36 and stainless steel 304 are used in the several pipelines and equipment of the marine industry and are exposed to aggressive environments favoring corrosion and material wear. For this reason, much research is focused on the development of new coatings and corrosion inhibitors. Polyaniline (PANI) is a conductive polymer widely used for its protective properties. In this work, samples of these materials were coated with commercial anti-corrosion paints based on epoxy additives with PANI /vanadium dioxide and PANI /graphite in different proportions. The corrosion performance of the coatings with increasing immersion time was performed by electrochemical impedance spectroscopy in 1M HCl solution. This test allowed the determination of the resistances (Rc) and capacitances (Cc) of the coatings, load transfer resistance (Rct) and capacitance of the electric double layer (Cdl) through simulations by equivalent electric circuits. In most coatings, the time increase contributed to a reduction in protection and the adition of 0.5% PANI/Vanadium dioxide showed greater efficiency in the protection against corrosion among other additions. To evaluate the adhesion of the coating to the substrate scratch tests were performed using a tungsten carbide cutting tool, following the configuration: scratching speed of 0.1 mm/s and normal load ranging from 1 to 8 N. In these tests were analyzed the critical load, the scratch hardness, the fab factor, which evaluates the ratio of the area of the material displaced to the side and area of scratch groove, the degree of penetration, which is a relation between the depth and the width of the scratch. In all the coatings the predominant micromechanisms was microcutting and the 0.5PV sample of carbon steel showed the best behavior regarding the resistance to wear.