Corrosion resistance of Cr2O3 coatings measured through EIS

Abstract

This paper present the results of corrosion resistance of commercial coatings of chromium oxide Cr2O3 deposited by thermal spray on phosphor bronze substrates with three methods of surface preparation: shot blasting with sand, blasting metal with alumina and polishing with abrasive disc, the three surfaces were prepared with and without base layer. The roughness of the deposited coatings was determined by confocal microscopy and the surface morphology was assessed by scanning electron microscopy (SEM); the crystal structure was determined by X-ray diffraction (XRD) and the corrosion resistance was evaluated via electrochemical impedance spectroscopy (EIS). The results of confocal microscopy showed that the surface roughness has a maximum value of 19,831 ?m; XRD analysis showed that the coatings have the same crystal structure of the powders; SEM analysis shows that the surface is porous and inhomogeneous. Finally, the EIS results, reveal that prepared surface with blasting had the best corrosion resistance.