Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings

Cold spraying as a low-temperature coating deposition method is intended for thermally sensitive materials. Due to its precise temperature control, it limits the formation of structural defects, and can therefore be easily applied to spray corrosion protective coatings made from metal or metal-ceram...

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Main Authors: M.M. Lachowicz, M. Winnicki
Format: Article
Language:English
Published: Polish Academy of Sciences 2022-08-01
Series:Archives of Metallurgy and Materials
Subjects:
Online Access:https://journals.pan.pl/Content/124025/PDF/AMM-2022-3-22-Winnicki.pdf
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author M.M. Lachowicz
M. Winnicki
author_facet M.M. Lachowicz
M. Winnicki
author_sort M.M. Lachowicz
collection DOAJ
description Cold spraying as a low-temperature coating deposition method is intended for thermally sensitive materials. Due to its precise temperature control, it limits the formation of structural defects, and can therefore be easily applied to spray corrosion protective coatings made from metal or metal-ceramic powders. However, the formation of pure ceramic coatings with the use of cold spraying is still not so common. Titanium dioxide is one of the most interesting ceramics due to its photocatalytic properties. Nevertheless, these types of coating materials usually work in a corrosion favoring humid atmosphere. In the presented paper, amorphous TiO2 powder was deposited onto aluminum alloys and steel substrates and then submitted to potentiodynamic corrosion tests in a 3.5 wt.% NaCl solution. The as-sprayed coating showed phase transition from amorphous TiO2 to anatase, and also revealed porosity. As a result, electrolytes penetrated the coating and caused undercoating corrosion in the tested environment of an aqueous NaCl solution. The analysis of the potentiodynamic curves showed that the presence of the coating decreased corrosion potential on both substrates. It arose from the mixed phases of TiO2, which consisted of photocathode – amorphous material and photoanode – crystalline anatase. The phase mixture induced the galvanic corrosion of metallic substrates in the presence of electrolytes. Moreover, pitting-like corrosion and coating delamination were detected in aluminium alloy and steel samples, respectively. Finally, the corrosion mechanism of the titanium dioxide coatings was characterized and described.
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spelling doaj.art-dca122d761ef4d7cb5f0001372ab79d02022-12-22T04:19:02ZengPolish Academy of SciencesArchives of Metallurgy and Materials2300-19092022-08-01vol. 67No 3975985https://doi.org/10.24425/amm.2022.139691Corrosion Damage Mechanisms of TiO2 Cold-Sprayed CoatingsM.M. Lachowicz0M. Winnicki1https://orcid.org/0000-0003-2766-116XWrocław University of Science and Technology, Department of Metal Forming, Welding and Metrology, 5 Lukasiewicza S tr., 50-371 Wroclaw, PolandWrocław University of Science and Technology, Department of Metal Forming, Welding and Metrology, 5 Lukasiewicza S tr., 50-371 Wroclaw, PolandCold spraying as a low-temperature coating deposition method is intended for thermally sensitive materials. Due to its precise temperature control, it limits the formation of structural defects, and can therefore be easily applied to spray corrosion protective coatings made from metal or metal-ceramic powders. However, the formation of pure ceramic coatings with the use of cold spraying is still not so common. Titanium dioxide is one of the most interesting ceramics due to its photocatalytic properties. Nevertheless, these types of coating materials usually work in a corrosion favoring humid atmosphere. In the presented paper, amorphous TiO2 powder was deposited onto aluminum alloys and steel substrates and then submitted to potentiodynamic corrosion tests in a 3.5 wt.% NaCl solution. The as-sprayed coating showed phase transition from amorphous TiO2 to anatase, and also revealed porosity. As a result, electrolytes penetrated the coating and caused undercoating corrosion in the tested environment of an aqueous NaCl solution. The analysis of the potentiodynamic curves showed that the presence of the coating decreased corrosion potential on both substrates. It arose from the mixed phases of TiO2, which consisted of photocathode – amorphous material and photoanode – crystalline anatase. The phase mixture induced the galvanic corrosion of metallic substrates in the presence of electrolytes. Moreover, pitting-like corrosion and coating delamination were detected in aluminium alloy and steel samples, respectively. Finally, the corrosion mechanism of the titanium dioxide coatings was characterized and described.https://journals.pan.pl/Content/124025/PDF/AMM-2022-3-22-Winnicki.pdftitanium dioxidecold-sprayed coatingspotentiodynamic polarization testsaluminum alloysstructural steel
spellingShingle M.M. Lachowicz
M. Winnicki
Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
Archives of Metallurgy and Materials
titanium dioxide
cold-sprayed coatings
potentiodynamic polarization tests
aluminum alloys
structural steel
title Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
title_full Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
title_fullStr Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
title_full_unstemmed Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
title_short Corrosion Damage Mechanisms of TiO2 Cold-Sprayed Coatings
title_sort corrosion damage mechanisms of tio2 cold sprayed coatings
topic titanium dioxide
cold-sprayed coatings
potentiodynamic polarization tests
aluminum alloys
structural steel
url https://journals.pan.pl/Content/124025/PDF/AMM-2022-3-22-Winnicki.pdf
work_keys_str_mv AT mmlachowicz corrosiondamagemechanismsoftio2coldsprayedcoatings
AT mwinnicki corrosiondamagemechanismsoftio2coldsprayedcoatings