Corrosion resistance of sol-gel ZrO2 coatings deposited on stainless steel

Abstract

Corrosion-resistant ZrO2 coatings were deposited on stainless steel plates using organic (A) and inorganic (B) Zr precursors containing polyethylene glycol as structure directing agent. The dipping-drying cycles were repeated five times; the coatings were then treated at 500 °C. The samples were studied by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and by automated contact-angle goniometry. The corrosion resistance of the ZrO2 coatings were examined in NaCl and artificial sea water. The XRD analyses revealed a crystallized monoclinic ZrO2 phase. The AFM observation proved that after the corrosion attack the surface had no signs of corrosion (scratches or cracks). The A and B coatings had corrosion rates of 4×10−5 and 2×10−4 g/m2 h, respectively. The A coatings possessed a fine grained structure and a lower wettability (contact angle of 107°) and a lower oxygen content than the B coatings, which determined their better corrosion properties in both corrosive media.