TY - JOUR
T1 - Fabrication and characterization of ceramic coating on al7075 alloy by plasma electrolytic oxidation in molten salt
AU - Sobolev, Alexander
AU - Peretz, Tamar
AU - Borodianskiy, Konstantin
N1 - Publisher Copyright:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2020/10
Y1 - 2020/10
N2 - The fabrication of a ceramic coating on the metallic substrate is usually applied to achieve the improved performance of the material. Plasma electrolytic oxidation (PEO) is one of the most promising methods to reach this performance, mostly wear and corrosion resistance. Traditional PEO is carried out in an aqueous electrolyte. However, the current work showed the fabrication and characterization of a ceramic coating using PEO in molten salt which was used to avoid disadvantages in system heating-up and the formation of undesired elements in the coating. Aluminum 7075 alloy was subjected to the surface treatment using PEO in molten nitrate salt. Various current frequencies were applied in the process. Coating investigations revealed its surface porous structure and the presence of two oxide layers, α-Al2 O3 and γ-Al2 O3 . Microhardness measurements and chemical and phase examinations confirmed these results. Potentiodynamic polarization tests and electrochemical impedance spectroscopy revealed the greater corrosion resistance for the coated alloy. Moreover, the corrosion resistance was increased with the current frequency of the PEO process.
AB - The fabrication of a ceramic coating on the metallic substrate is usually applied to achieve the improved performance of the material. Plasma electrolytic oxidation (PEO) is one of the most promising methods to reach this performance, mostly wear and corrosion resistance. Traditional PEO is carried out in an aqueous electrolyte. However, the current work showed the fabrication and characterization of a ceramic coating using PEO in molten salt which was used to avoid disadvantages in system heating-up and the formation of undesired elements in the coating. Aluminum 7075 alloy was subjected to the surface treatment using PEO in molten nitrate salt. Various current frequencies were applied in the process. Coating investigations revealed its surface porous structure and the presence of two oxide layers, α-Al2 O3 and γ-Al2 O3 . Microhardness measurements and chemical and phase examinations confirmed these results. Potentiodynamic polarization tests and electrochemical impedance spectroscopy revealed the greater corrosion resistance for the coated alloy. Moreover, the corrosion resistance was increased with the current frequency of the PEO process.
KW - Al7075 alloy
KW - Aluminum oxide
KW - Corrosion resistance
KW - Microhardness
KW - Molten salt
KW - Plasma electrolytic oxidation (PEO)
UR - http://www.scopus.com/inward/record.url?scp=85093815785&partnerID=8YFLogxK
U2 - 10.3390/coatings10100993
DO - 10.3390/coatings10100993
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AN - SCOPUS:85093815785
SN - 2079-6412
VL - 10
SP - 1
EP - 12
JO - Coatings
JF - Coatings
IS - 10
M1 - 993
ER -