Rust Preventive Properties by Using Polarization Curve Measurement on the Metal Coated with the Rust Preventive Oil

Abstract

Fe-Cu-C sintered steels are widely used as powder materials, because of its small volumetric shrinkage. However, Cu, which acts as cathode enhance formation of rust (Fe₂O₃·xH₂O) during fabrication. To prevent formation of Fe₂O₃·xH₂O rust preventive oils are genially used. Therefore, it is necessary to develop new rust preventive oils with contradictory properties of low viscosity and superior rust prevention. In this study, we developed technique to quantitatively evaluate rust prevention ability by measuring polarization curve through thin corrosive solution on Fe-Cu-C sintered steels coated with rust preventive oils. Polarization curves were registered after 30 min of exposure to test solution in order to allow corrosion potential (E_corr) stabilization. From the experimental, it is possible to evaluate the corrosion rate quantitatively in the surface of specimen, which was coated with rust preventive oil through thin corrosive solution. The measurement results suggest the anodic reaction is decreased with oils.