Improvement of wear-resistance and anti-corrosion of waterborne epoxy coating by synergistic modification of glass flake with phytic acid and Zn2+

Waterborne epoxy (WEP) coatings have been widely applied in the industry due to their environmental friendliness. However, the original defects of WEP coatings significantly affect their mechanical properties and corrosive resistance. A type of modified filler has been designed and fabricated to improve the wear resistance and anti-corrosion properties of WEP coatings. First, glass flakes (GF) have been modified with 3-Triethoxysilylpropylamine (kh560) to improve their surface activity and endow epoxy groups. Subsequently, the PA-Zn2+-m-GF hybrids have been fabricated via the grafting of phytic acid (PA) and zinc ions (Zn2+) on the surface of modified GF fillers (m-GF). PA and Zn2+ are more firmly grafted onto the surface of GF, owing to the functionality of kh560. The obtained PA-Zn2+-m-GF hybrids serve as fillers to substantially boost the wear resistance and anti-corrosion of WEP coating. The PA-Zn2+-m-GF/WEP coating exhibits good wear-resistant and excellent anti-corrosion properties at 20 wt% filler content. The related thickness loss is about 30% after 1000 cycles of friction experiments, and the impedance modulus maintains above 107 Ω cm2 after 144 h of immersion in 3.5 wt% NaCl solution. The anti-corrosion system is constituted by the synergy of organic and inorganic inhibitors and the corresponding anti-corrosion mechanism in WEP coating has been thoroughly discussed in this work.