Synthesis and Characterization of Anti-Scratch and Anti-Corrosion Hybrid Nanocomposite Coatings Based on Sol-Gel Process

Abstract

Hybrid nanocomposite coatings containing SiO2, TiO2, ZnO, and ZrO2 particles were synthesized based on sol-gel precursors, including tetraethoxysilane (TEOS), 3glycidoxypropyl trimethoxysilane (GPTMS), tetra(n-butylorthotitanate) (TBT), zinc acetate dihydrate, and zirconium chloride (IV). The nanocomposites were characterized using FTIR, SEM, DLS, and EDAX methods. Results indicated that the size of the inorganic particles was in the range of nanometer (283.3, 163.5, 99.2, and 2.5 nm for ZrO2, SiO2, ZnO, and TiO2, respectively) with a very uniform distribution and dispersion. Hybrid nanocomposite coatings containing different amounts of nanozirconia were prepared on a 30-μm thick steel sheet for the subsequent scratch test. The highest scratch resistance of 3950 g was associated with the coating containing 0.0015 g nanozirconia. The electrochemical properties of the composite coating were investigated using potentiodynamic polarization (TOEFL) and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion resistance of the steel sheet coated with zirconia composite is much better than that without the coating. The ZrO2 composite coating also showed better corrosion inhibition and improving surface resistance against mechanically induced scratches, without any trade-off in transparency.