Enhancement of corrosion protection of AISI 201 austenitic stainless steel in acidic chloride solutions by Ce-doped TiO₂ coating
Gaber, Ghalia A.; Mohamed, Lamiaa Z.; Järvenpää, Antti; Hamada, Atef (2021-08-14)
Ghalia A. Gaber, Lamiaa Z. Mohamed, Antti Järvenpää, Atef Hamada, Enhancement of corrosion protection of AISI 201 austenitic stainless steel in acidic chloride solutions by Ce-doped TiO2 coating, Surface and Coatings Technology, Volume 423, 2021, 127618, ISSN 0257-8972, https://doi.org/10.1016/j.surfcoat.2021.127618
© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
https://urn.fi/URN:NBN:fi-fe2021111054562
Tiivistelmä
Abstract
Ce-doped TiO₂ coatings were applied by electrodeposition on a low-nickel austenitic stainless steel (AISI 201) bearing 8 wt% Mn to improve the electrochemical properties in acidic chloride solutions. Characterization of the Ce-doped TiO₂ coatings was performed by a scanning electron microscope equipped with energy dispersive X-ray spectroscopy (EDS) to study the tiny features. The corrosion behavior of the bare and coated steel was evaluated in aqueous acidic chloride solutions mixing with different chloride concentrations, 1 mol·L⁻¹ H₂SO₄ with 0–1.5% NaCl. Potentiodynamic polarization tests were conducted to evaluate the corrosion characteristics, corrosion potential Ecorr and corrosion current density icorr. Further study concerning the weight loss (WL) using immersion tests for the long-term was conducted to determine the bare and corresponding coated steel’s equivalent corrosion rates.
It was found that the electrodeposited Ce-doped TiO₂ coatings with a layer thickness of ~1 μm enhance the corrosion resistance of the coated steel in the acidic chloride solutions compared to its counterpart, the bare steel. The polarization tests showed that the icorr of the Ce-doped TiO₂ coated steel significantly declined to a half value of the bare steel. The Ecorr for all coated specimens shifted to a more positive value when compared with those of the bare steel. The WL measurements displayed that the bare AISI 201 steel experiences intensive corrosion degradation in the presence of a low concentration of chloride ions. However, the Ce-doped TiO₂ coatings significantly resist the aggressive chloride ions and consequently increase the corrosion resistance of the steel.
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