Evaluation of corrosion protection performance and color stability of environment-friendly pigmented polyurethane coating

Abstract

This research is distinctive in its focus on the corrosion protection property, the ultraviolet B radiations (UV-B) resistance, and the color stability of a polyurethane (PU) base coating formulated with 1 % wt. of an environment-friendly inorganic pigment (Bi, Ca, Zn)VO₄. The pigment was synthesized and evaluated based on structure, color, and the sizes of particles. The phase composition of the synthesized pigment was studied using X-ray diffraction (XRD) analysis. Notably, the pigment's color slightly changed with its calcination's temperature, transitioning from yellow to orange. The coatings produced with a PU binder and 1 % wt. of pigment resulted in a yellow-colored coating. The color and the coating stability, as well as the barrier property of selected pigmented PU coatings, were investigated using the CIEL*a*b* color system, Fourier Transformed Infrared (FTIR) spectroscopy, and electrochemical impedance spectroscopy (EIS). The results demonstrated excellent color stability, as well as good protective barrier properties of the pigmented coating. The coatings also exhibited strong chemical stability and UV-B resistance. The high corrosion resistance and the reinforcement of the protection barrier properties of coatings were achieved via well-dispersion of the (Bi, Ca, Zn)VO₄ powder in the polymer matrix.