Abstract
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.
| Original language | English |
|---|---|
| Article number | 993 |
| Pages (from-to) | 1-12 |
| Number of pages | 12 |
| Journal | Coatings |
| Volume | 10 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2020 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Funding
Authors wish to express their gratitude to Alexey Kossenko and Natalia Litvak from the Engineering and Technology Unit at the Ariel University for their assistance in XRD and SEM investigations.
| Funders | Funder number |
|---|---|
| Engineering and Technology Unit |
Keywords
- Al7075 alloy
- Aluminum oxide
- Corrosion resistance
- Microhardness
- Molten salt
- Plasma electrolytic oxidation (PEO)