Nuclear chemistry

Dielectric spectroscopy

Polymer chemistry

Epoxy

Electrochemistry

Metallurgy

Materials science

Polyamide

Coating

Layer (electronics)

Phosphate

Zinc

Physical chemistry

Organic chemistry

Composite material

Polyphosphate

Corrosion

Chemistry

Electrode

Aluminium

Corrosion Science

This work investigates the synergetic effect of zinc aluminum polyphosphate (ZAPP) and 2-mercaptobenzimidazole (MBI) on the corrosion protection of mild steel coated with a solvent-borne epoxy-polyamide layer. The magnitude and trend of electrochemical impedance spectroscopy data over 70-d immersion in 3.5 wt.% NaCl solution indicate superior corrosion protection of the combined inhibitors compared to those containing either just ZAPP or MBI. Pull-off tests show that the combined inhibitor system provides an improved adhesion strength. The enhanced corrosion performance is correlated to precipitation of a protective layer at the coating/metal interface verified by SEM and electrochemical studies upon exposure to electrolytes.

Enhanced corrosion protection of mild steel by the synergetic effect of zinc aluminum polyphosphate and 2-mercaptobenzimidazole inhibitors incorporated in epoxy-polyamide coatings