Corrosion resistant ZrO2 sol-gel coating on stainless steel

Abstract

Corrosion resistant sol-gel ZrO2 coatings deposited by dip coating technique on 316 L stainless steel sheets have been fabricated utilizing sonocatalysed precursors sols prepared from zirconium alkoxide Zr(OC3H7)4, isopropanol, glacial acetic acid and water. Their composition varied between 0,025 to 0,9 mol/l ZrO2. The coatings have been characterized by X-ray diffraction, IR optical reflection, ellipsometry and scanning electron microscopy. When densified under a slow heat treatment thin coatings exhibit outstanding corrosion resistance as no weight change has been observed after 24 h chemical attack in H2SO4 aqueous solution at 81°C and 10 h oxidation treatment in air at 800°C. Thick films as well as films densified under rapid heat treatments tend to crack and are less corrosion resistant.