Oxidation protection of mild steel by zirconia sol-gel coatings

Zirconia coatings were deposited on a mild steel substrate by the sol-get method. The interface between the coating and substrate was analyzed by Auger electron spectroscope (AES). The oxidation kinetics during iron oxide formation was investigated by measuring weight gain in the temperature range of 450-550 degreesC. The sample surfaces after oxidation were characterized by scanning electron microscopy and X-ray diffraction (XRD). The experimental results showed that the zirconia coatings at moderate temperature increased the activation energy of oxidation from 32 to 58 kJ mol(-1). suppressed the growth of iron oxides, and substantially reduced the oxidation rate of the substrate. (C) 2001 Elsevier Science B.V. All rights reserved.