Zinc-free varnishes and zinc-rich paints modified with ionic liquids

• Ionic liquids as modifiers of zinc-rich paints.
• Ionic liquids significantly reduce an electrical resistivity of a polymeric binder.
• Imidazolium ionic liquid improves the corrosion protection properties of zinc-rich coats cured on a steel substrate.
• Pyrrolidinium ionic liquid significantly reduces the corrosion rates of steel and zinc.

The corrosion protection of a steel substrate using zinc-rich epoxy–alkyd paints (ZRPs) modified with either 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF6) or 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyrrTFSI) has been investigated. Additionally, the influence of ionic liquids (ILs) on the corrosion process of uncoated steel and zinc as well as on electrical features of zinc-free varnishes has been evaluated. The pyrrolidinium IL significantly reduces the corrosion rates of steel and zinc but the ZRPs with HMIMPF6 offer better cathodic protection of steel than unmodified ZRP and ZRPs with BMPyrrTFSI. The electrical conductivity of IL is not critical for the protective features of ZRP.