Improvement of rust prevention by inclusion of 2D zeolite and graphene in oil-based soft coating

Abstract

Rust preventives (RPs) are often employed to protect carbon steel from atmospheric corrosion during manufacture, storage, and/or transportation. In this work, commercial oil-based RPs containing graphene and PREFER were tested as protective layers on SAE 1006 steel. PREFER is a bi-dimensional/layered zeolite formed by ordered ferrierite layers. X-ray diffraction analysis confirmed formation of the zeolite. Electrochemical impedance spectroscopy results showed that the presence of graphene and PREFER in the RP provided ten-fold higher resistance than the RP without additives, after 22 h of immersion in 0.1 mol L⁻¹  NaCl. On the other hand, the RP containing delaminated PREFER provided no corrosion protection, confirming the bidimensional effect of the filler in the oil-based RP. Salt spray and humidity test results corroborated the electrochemistry data. The steel sample coated with RP_PREFER-CTAB presented red corrosion on less than 10 % of the surface. The sample coated with RP_G did not present corrosion and the coating was easier to remove using alkaline cleaning solution, indicating its superiority as a temporary coating, compared to RP_PREFER-CTAB and the oil containing only sulfonate inhibitor.