Oxidation protection of mild steel by zirconia sol-gel coatings

Zirconia coatings were deposited on mild steel substrate by the sol-gel method. The interface between the coating and substrate was analyzed by Auger electron spectroscope (AES). The oxidation kinetics during iron oxide formation has been investigated by measuring weight gain in the temperature range of 450degreesCsimilar to550degreesC. The sample surfaces after oxidation were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results show that the zirconia coatings at moderate temperature increased the activation energy of oxidation from 32kJ . mol(-1) to 58 kj . mol(-1) suppressed the growth of iron oxide's and substantially reduced the oxidation rate of the substrate.