Protection of 316L stainless steel by zirconia sol-gel coatings in 15% H sub 2 SO sub 4 solutions

• Published in: Journal of materials science letters Vol. 14; no. 3; pp. 178 - 181
• Main Authors: Atik, M, Kha, C R, De Lima Neto, P, Avaca, L A, Aegerter, M A, Zarzycki, J
• Format: Journal Article
• Language: English
• Published: 01.02.1995
• ISSN: 0261-8028

ZrO sub 2 was prepared on 316L stainless steel substrates by dip-coating using a sol preparation involving sonocatalysis (ultrasound irradiation using a transducer). Zirconium isopropoxide diluted in isopropanol was used as the source of zirconia. The substrates were degreased, dipped, heated to remove organic residues and oxidized in air at 800 deg C to obtain adherent and dense coatings. Corrosion characteristics of the samples, either the bare substrate or coated with ZrO sub 2 , were evaluated through potentiodynamic polarization curves, while ZrO sub 2 thin film structure was characterized by x-ray diffraction and the ZrO sub 2 surface was observed by scanning electron microscopy. The potendiodynamic polarization curves showed that combined cathodic and anodic effects produced results such as corrosion rate approx8.4 times lower at 40 deg C for coated substrates. Sol-gel coatings of ZrO sub 2 prepared as described are thus concluded to protect the metallic substrate against acid corrosion, with the film acting as a geometric blocking layer.