Effect of silicon carbide nanoparticles on the properties of polyurethane coatings applied on steel substrates

In the present study, nanocomposites with 1, 2 and 3% wt. nano-silicon carbide in polyurethane coating was prepared by solution mixing method and the sanding method was applied on substrate preparation. Pull-off test was used to evaluate the adhesion strength of the coating to the substrate. The protective properties of the produced coatings were investigated using Potentiodynamic polarization test. Abrasion resistance of the coatings was evaluated using Roller on plate method. Also, in order to study surface abrasion, morphology of the coatings and dispersion of nanoparticles, field emission scanning electron microscope images (FE-SEM) was used. Thermal bar graph analysis was used to study the thermal stability of the coatings. The results showed that the presence of 2 % wt. of nanoparticles, leads to the improvement of the adhesion strength up to 37.7%, abrasion resistance up to about 42% and increase of the onset decomposition temperature up to 51%. Furthermore, the corrosion current density of steel increased up to 3.5%, and the corrosion rate increased 1.8% in comparison to pure polyurethane. The mechanical properties of nanocomposites containing 3 % wt. of nano-silicon carbide faced a relative decline compared to nanocomposite with 2 % wt., due to particle aggregation.