Comparative study of the effect of halloysite nanocontainers on autonomic corrosion protection of polyepoxy coatings on steel by salt-spray tests

The comparative study was carried out to show the effect of the halloysite nanotubes loaded with three inhibitors with different properties (Korantin SMK, Halox 520 and (NH4)(2)TiF6) as an additive for autonomic corrosion protection of polyepoxy coating on steel substrate. The comparison was carried out employing neutral salt-spray test (5% NaCl, 35 degrees C, different time). Commercial polyepoxy coating containing 20 wt% of zinc phosphate was used as a benchmark during testing. We demonstrated that inhibitor-loaded halloysites at 5 wt% concentration are able to successfully substitute 20 wt% zinc phosphate in the commercial polyepoxy coating even improving its corrosion protection performance, which depends in a large extend on the release profiles of the inhibitors loaded into halloysite nanotubes. On the contrary, addition of the free inhibitors into the coating showed complete deterioration of the corrosion protection properties for all inhibitors.