Corrosion Behavior of Aerosol Thermal Sprayed ZrO2 Coatings
Authors: Di Giampaolo A.R.; Gonz´lez Y.; Gutiérrez-Campos D.
Source: Advanced Performance Materials, Volume 6, Number 1, May 1999 , pp. 39-51(13)
ZrO2 coatings of 27 m thickness were obtained by the aerosol thermal spraying process on 316L stainless steel. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed that these films consisted of nanocrystalline ZrO2 aggregates with a monoclinic structure. Corrosion tests were performed in aqueous NaCl (0.5 M) and H2SO4 (20 wt%) using potentiodynamic cyclic polarization curves. Surfaces and cross-sections of coated samples were compared with the uncoated substrate. This evaluation indicated decreased pitting of the steel with coating. The protection against corrosion in NaCl solution depended strongly on coating thickness. No protection was found for thicknesses less than 5 m. Meanwhile, a marked reduction of the current density was produced by thicker coatings that acted as an effective corrosion barrier. Coatings thicker than 5 m also provided significant protection against corrosion in H2SO4.
Document Type: Regular paper
Publication date: 1999-05-01