Comptes rendus de l’Acade'mie bulgare des Sciences, Vol 72, No1, pp.55-61

Sol-gel CeO₂ and ZrO₂ Coatings on CeO₂: Study of the Phase Composition, Morphology and Corrosion Resistance

Stancho I.Yordanov, Irina D.Stambolova, Luben I.Lakov, Sasho V.Vassilev, Bojidar T.Jivov

ABSTRACT

Cerium dioxide and zirconium dioxide coatings deposited on CeO₂ underlayers were obtained by sol-gel method on stainless steel plates. The samples were studied by Scanning electron microscopy (SEM), AFM and X‑ray diffraction analyses. The corrosion resistance of the CeO₂/ZrO₂ coatings were examined in salty solution of 3.5% NaCl. The XRD analyses revealed well crystallized CeO₂ and ZrO₂ cubic phases. All coatings possess relatively smooth, uniform surface. It was proved that the temperature of heat treatment of the ZrO₂ coatings has significant influence on the protective properties of the coatings. The increasing of the treatment temperature of ZrO₂ effects in a lower corrosion resistance of the coatings. The CeO₂, treated at 300⁰C and covered by ZrO₂ coating, treated at 500⁰C exhibited the best protective properties in NaCl medium. After corrosion test they have revealed almost unchanged surface structure without any pits. The evaluated corrosion rate of the same coatings is lower than those of uncoated steel.

Key words: sol-gel, multilayers, nanosized films, anticorrosive coatings

Topic: CHEMISTRY