Abstract
The plasma electrolytic oxidation (PEO) method is one of the most promising methods for the formation of oxide coatings on metallic substrates. This process is usually conducted in an aqueous solution electrolyte; however, it has several disadvantages, such as heating-up of the system and the formation of the undesired chemical components. This study addresses these disadvantages by conducting the process in a molten salt electrolyte. The surface morphology, phase composition, hydrophobicity, and the effects of process current frequency were examined. Thin titanium oxide, rutile and anatase, coating of 2–2.5 μm was formed on the treated Ti-6Al-4V alloys. The potentiodynamic polarization test evaluated the highest polarization polarization resistance for the alloy obtained using current frequency of 150 Hz which was 364×104 Ω·cm2 in comparison with the pristine alloy which was 6.93×104 Ω·cm2. Electrochemical impedance spectroscopy revealed the same behavior. Morphology evaluation revealed that the structure of this coating contained uniform sub-micron porosity and its surface exhibited the highest hydrophobicity.
Original language | English |
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Article number | 126847 |
Journal | Surface and Coatings Technology |
Volume | 408 |
DOIs | |
State | Published - 25 Feb 2021 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021 Elsevier B.V.
Funding
Authors wish to express their gratitude to Dr. Alexey Kossenko and Ms. Natalia Litvak from the Engineering and Technology Unit at the Ariel University for their assistance in XRD and SEM investigations, and to Prof. Michael Talianker from the Ben Gurion University of the Negev for his valuable discussion of XRD results. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Funders | Funder number |
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Ben Gurion University | |
Engineering and Technology Unit |
Keywords
- Molten salt
- Morphology
- Plasma electrolytic oxidation
- Titanium alloy