Desenvolvimento de um novo revestimento polimérico utilizando pentóxido de nióbio como pigmento branco anticorrosivo a partir do ácido nióbico como precursor

Abstract

Pigments are widely applied in industrial coatings to impart color, brightness and corrosion protection, especially in metallic structures. The white pigment is the most widely used worldwide, and titanium dioxide rutile main, mainly due to its high refractive index and low and uniform light absorption. The use of different metals for the purpose of production of anticorrosive coatings has been widely studied and are already pigments with corrosion protection superior to titanium, but with much higher price due to various treatments. However, we can highlight the niobium pentoxide as a strong competitor to titanium dioxide, because present inert to human body, 60% of its deposits are located in national territory and for being remarkably resistant to most aggressive compounds and, consequently, corrosion. The niobium pentoxide is stable, insoluble in water, and difficult to reduce white solid, which can be obtained by calcining the niobic acid at high temperatures. The calcination removes the water and transform the amorphous niobium pentoxide in different crystalline forms depending on the temperature that is treated, this is an irreversible transformation. The objective of this work is the application of niobium pentoxide as a white pigment in corrosion-resistant polymer coating. For this, heat treatment is undertaken in the niobic acid to obtain niobium pentoxide at different temperatures. The materials were characterized by the techniques of x-ray diffraction and scanning electron microscopy. These materials are used in a paint formulation and then be compared with titanium dioxide, and analyzed their corrosion resistances. Finally, we evaluated the final cost of each formulation containing pigments. The results showed that the use of niobium pentoxide can be considered an alternative in cases where there is no titanium dioxide available for use as a pigment for paint formulations.