Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 10990-10998 |
| Number of pages | 9 |
| Journal | Ceramics International |
| Volume | 48 |
| Issue number | 8 |
| DOIs | |
| State | Published - 15 Apr 2022 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021 Elsevier Ltd and Techna Group S.r.l.
Funding
Authors wish to express their gratitude to Dr. Alexey Kossenko, Dr. Olga Krichevsky and Ms. 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
- A. Films
- B. Electron microscopy
- B. X-ray methods
- C. Corrosion
- D. AlO