Fabrication and Characterization of Ceramic Coating on Al7075 Alloy by Plasma Electrolytic Oxidation in Molten Salt

Coatings

Konstantin Borodianskiy¹  Tamar Peretz¹  Alexander Sobolev¹ 

[1] Department of Chemical Engineering, Ariel University, Ariel 40700, Israel;

关键词: plasma electrolytic oxidation (PEO);    Al7075 alloy;    aluminum oxide;    molten salt;    microhardness;    corrosion resistance;   

DOI  :  10.3390/coatings10100993

来源: DOAJ

【 摘 要 】

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-Al₂O₃ and γ-Al₂O₃. 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.

【 授权许可】

Unknown