TY - JOUR
T1 - Evolution of corrosion on microstructure of ceramic coating produced by plasma electrolytic oxidation in molten salt
AU - Sobolev, A.
AU - Bograchev, D.
AU - Zinigrad, M.
AU - Borodianskiy, K.
N1 - Publisher Copyright:
© 2021 Elsevier Ltd and Techna Group S.r.l.
PY - 2022/4/15
Y1 - 2022/4/15
N2 - Low corrosion resistance in an Al alloy is usually overcome with the help of an Al oxide coating. Plasma electrolytic oxidation (PEO) is a highly promising environment-friendly method to achieve a ceramic surface. Traditionally, PEO is carried out in an aqueous electrolyte; however, in this study, PEO was conducted in a molten salt. This approach conserved more energy and led the formation of a pure oxide coating, as confirmed by subsequent phase analysis. The obtained ceramic coating contained two sublayers: a porous outer sublayer and a dense inner sublayer. A study of corrosion evolution was performed on oxide-coated alloys immersed in a NaCl solution for different durations. The corrosion behavior characterized by electrochemical impedance spectroscopy (EIS) was related to the changes in the surface morphology changes examined by electron microscopy. The appearance of pits on the oxide surface was attributed to the adsorption and incorporation theory, previously described for Al alloys. This study revealed that the progress of the corrosion attack by chloride ions affects both sublayers; the thickness of the outer sublayer decreased, and the inner sublayer became more compact, resulting in high resistance properties.
AB - Low corrosion resistance in an Al alloy is usually overcome with the help of an Al oxide coating. Plasma electrolytic oxidation (PEO) is a highly promising environment-friendly method to achieve a ceramic surface. Traditionally, PEO is carried out in an aqueous electrolyte; however, in this study, PEO was conducted in a molten salt. This approach conserved more energy and led the formation of a pure oxide coating, as confirmed by subsequent phase analysis. The obtained ceramic coating contained two sublayers: a porous outer sublayer and a dense inner sublayer. A study of corrosion evolution was performed on oxide-coated alloys immersed in a NaCl solution for different durations. The corrosion behavior characterized by electrochemical impedance spectroscopy (EIS) was related to the changes in the surface morphology changes examined by electron microscopy. The appearance of pits on the oxide surface was attributed to the adsorption and incorporation theory, previously described for Al alloys. This study revealed that the progress of the corrosion attack by chloride ions affects both sublayers; the thickness of the outer sublayer decreased, and the inner sublayer became more compact, resulting in high resistance properties.
KW - A. Films
KW - B. Electron microscopy
KW - B. X-ray methods
KW - C. Corrosion
KW - D. AlO
UR - http://www.scopus.com/inward/record.url?scp=85122059790&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2021.12.318
DO - 10.1016/j.ceramint.2021.12.318
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AN - SCOPUS:85122059790
SN - 0272-8842
VL - 48
SP - 10990
EP - 10998
JO - Ceramics International
JF - Ceramics International
IS - 8
ER -