Corrosion studies on the plasma‐sprayed nanostructured titanium dioxide coatings

Abstract

PurposeThe purpose of this paper is to report the resistance of plasma‐sprayed titanium dioxide (TiO2) nanostructured coatings in a corrosive environment.Design/methodology/approachWeight loss studies are performed according to ASTM G31 specifications in 3.5 wt% NaCl. Electrochemical polarization resistance measurements are made according to ASTM G59‐91 specifications. Corrosion resistance in a humid and corrosive environment is determined by exposing the samples in a salt spray chamber for 100 h. Microstructural studies are carried out using an atomic force microscope and scanning electron microscope.FindingsThe nanostructured TiO2 coatings offer good resistance to corrosion, as shown by the results of immersion, electrochemical and salt spray studies. The corrosion resistance of the coating is dictated primarily by the geometry of splat lamellae, density of unmelted nanoparticles, magnitude of porosity and surface homogeneity.Practical implicationsThe TiO2 nanostructured coatings show promising potential for use as abrasion, wear‐resistant and thermal barrier coatings for service in harsh environments.Originality/valueThe paper relates the corrosion resistance of nanostructured TiO2 coatings to their structure and surface morphology.