The impact of stainless steel flakes as a novel multifunctional pigment for wood coatings

The purpose of this research was to determine the influence of three different amounts of stainless steel flakes on the aesthetic features and durability of a waterborne wood paint. Colorimetric measurements and optical microscope observations were employed to assess the impact of this novel pigment on the overall appearance of the coatings. The effect of the different amounts of metallic flakes on the durability of the layers was evaluated by subjecting the samples to UV-B radiation and cyclic thermal shocks, performing infrared spectroscopy analysis, colorimetric inspections, and adhesion test. In addition, the influence of the filler concentration on the coating barrier efficiency was assessed through the liquid resistance and water uptake tests. Moreover, Buchholz hardness indentation test and the scrub test were conducted to quantify the impact of the flakes on the mechanical characteristics of the coatings, such as hardness and abrasion resistance. Finally, the thermal test evidenced a specific role of the flake amount in altering the thermal behavior of the coatings. Ultimately, this work highlights the attractive effect of stainless steel flakes, which are capable of providing an intense coloring and specific aesthetic features to the paint, preserving the surface’s barrier-protective properties, increasing the abrasion resistance of the composite layer, and influencing the thermal behavior of the coating.