Chromate-free smart release corrosion inhibitive pigments containing cations

A smart release chrome-free inhibiting system is utilised in an organic coating system to inhibit cathodic disbondment of hot dip galvanised steel. The non-toxic smart release cation system is relatively cheap, easy to process and highly effective. An in-situ scanning Kelvin probe is used to assess the protection offered by the cation containing pigments in a poly-vinyl-butyral model coating. The inhibition of cathodic delamination under the SKP testing conditions exceeds that of hexavalent chromate by the inhibitor system containing magnesium(II) ions.