Development of steel coatings reinforced with nanoclay particles for corrosion and wear protection

During the last years, clay nanocomposites have attracted a lot of attention among research and industrial community. Recently, due to their great potential diverse fields, nanoclay reinforcements have been identified as interesting materials for a wide range of applications, such as additives in coatings, paints, inks and greases, as rheological modifiers, oil refining, catalyst, biocomposites, and thermal dissipators, among others. Montmorillonite (MMT) is a crystalline hydrous phyllosilicate (layer silicate), a clay fraction of soil which is one of the most important species of clays. MMT nanocomposite coating was fabricated by uniformly dispersing laminar nanoclay structures within enamel painting. In the present work, we evaluate the anti-corrosion and tribological performance of coatings reinforced with MMT nanoclay at various filler fractions, 0.1wt.%, 0.5wt.% and 1.0wt.%. Samples were evaluated on a salt spray (fog) chamber according to ASTM B117. Nanocoatings evaluation was performed according to ASTM D714; nanoclay reinforcement at 0.5wt.% improved up to 290% the corrosion resistance without any painting detachment, also improving ∼320% after displaying blistering on the surface, as compared to base painting, respectively. This is representative of the significant enhancement as a protective corrosion barrier of the nanopainting. Tribological evaluation was performed with a pin-on-disk tribotester, according to ASTM G99, to determine the anti-wear properties of the nanocoatings. Improvement in all nanocoatings concentrations was achieved, being the highest enhancement by the 0.10wt.% MMT nanocoating, which exceeded the conventional paint by ∼150%. This work gives a broad scope of opportunities for nanoclays reinforcing coatings and paintings for improvements on anti-corrosion and anti-wear performance, being a natural and environmentally friendly material.