Doping of zinc cations in chemically modified halloysite nanotubes to improve protection function of an epoxy ester coating

This paper deals with the loading of halloysite nanotubes (HNTs) with Zn2+ cations. The aluminol groups of HNTs were grafted by 3-aminopropyltriethoxysilane (APTES) to enhance Zn2+ loading. FTIR proved modification of HNTs. Electrochemical evaluations of bare steel in saline solution showed higher corrosion inhibition provided by an extract of modified HNTs connecting to a higher concentration of zinc cations released from modified HNTs. The HNTs were incorporated into an epoxy ester coating, and electrochemical behavior of intact and scratched coatings was evaluated. Active corrosion protection at the defect areas of the coatings was proved by EDS analysis.