Oxidation protection of mild steel by zirconia sol-gel coatings

Zirconia coatings were deposited on a mild steel substrate by the sol-get m ethod. The interface between the coating and substrate was analyzed by Auge r electron spectroscope (AES). The oxidation kinetics during iron oxide for mation was investigated by measuring weight gain in the temperature range o f 450-550 degreesC. The sample surfaces after oxidation were characterized by scanning electron microscopy and X-ray diffraction (XRD). The experiment al results showed that the zirconia coatings at moderate temperature increa sed 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.