Journal of the Korean institute of surface engineering (한국표면공학회지)

The Korean Institute of Surface Engineering (한국표면공학회)
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Lateral growth of PEO films on Al7050 alloy in 0.1 M NaAlO2

  • Moon, Sungmo (Surface Materials Division, Korea Institute of Materials Science) ;
  • Kim, Gi Yeob (Dept. of applied advanced materials, Changwon Campus of Korea Polytechnic)
  • Received : 2021.08.27
  • Accepted : 2021.08.30
  • Published : 2021.08.31
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Abstract

This paper investigated generation behavior of micro-arcs and growth behavior of PEO films on the AA7050 disc specimen in 0.1 M NaAlO2 solution under the application of 1200 Hz anodic pulse current. Morphologies, thickness and surface roughness of PEO films were examined at the edge part and central part separately. Micro-arcs were generated first at the edge part and then moved towards the central part with PEO treatment time, indicating lateral growth of PEO films. The lateral growth resulted in uniform PEO thickness of about 5 ㎛ and surface roughness of about 0.5 ㎛. Moving of the arcs from the edge towards the central part appeared only one time and large size arcs were generated at the edge before completing the central part with small size micro-arcs. This suggests that vertical growth starts before completing the lateral growth. Large size arcs generated at the edge resulted in the formation of relatively large size pores within the PEO films on the AA7050 disc specimen.

Keywords

Acknowledgement

This research was financially supported by Korea Institute of Materials Science (PNK7930) and by the Technology Development Program of the Ministry of SMEs and Startups (S2838879).

References

  1. Sanghyuck Moon, Sungmo Moon and Sugun Lim, Formation Characteristics of Hard Anodizing Films on 6xxx Aluminum Alloys, J. Kor. Inst. Surf. Eng. 52 (2019) 203-210.
  2. Sungmo Moon, Kihun Jeong, Sugun Lim. Formation Behavior of Anodic Oxide Films on Al 6061 Alloy in Sulfuric Acid Solution, J. Kor. Inst. Surf. Eng. 51 (2018) 393-399. https://doi.org/10.5695/JKISE.2018.51.6.393
  3. Sungmo Moon, Cheolnam Yang and Sangjo Na, Formation Behavior of Anodic Oxide Films on Al7075 Alloy in Sulfuric Acid Solution, J. Kor. Inst. Surf. Eng. 47 (2014) 155-161. https://doi.org/10.5695/JKISE.2014.47.4.155
  4. S. Moon, Y. Nam, Anodic oxidation of Mg-Sn alloys in alkaline solutions, Corrosion Science 65 (2012) 494-501. https://doi.org/10.1016/j.corsci.2012.08.050
  5. S. Moon, S. Pyun, The formation and dissolution of anodic oxide films on pure aluminium in alkaline solution, Electrochimica Acta 44 (1999) 2445-2454. https://doi.org/10.1016/S0013-4686(98)00368-5
  6. S. Moon, S. Pyun, The mechanism of stress generation during the growth of anodic oxide films on pure aluminium in acidic solutions, Electrochimica Acta 43 (1998) 3117-3126. https://doi.org/10.1016/S0013-4686(97)10194-3
  7. Juseok Kim, Heon-cheol Shin, and Sungmo Moon, Effect of Na3PO4 Concentration on the Formation Behavior and Properties of PEO Films on AA2024, Kor. Inst. Surf. Eng. 53 (2020) 351-359.
  8. SungmoMoon, Yeajin Kim, Lateral growth of PEO films on Al1050 alloy in an alkaline electrolyte, Kor. Inst. Surf. Eng. 50 (2017) 10-16. https://doi.org/10.5695/JKISE.2017.50.1.10
  9. SungmoMoon, Yeajin Kim, PEO film formation behavior of Al1050 alloy under direct current in an alkaline electrolyte, Kor. Inst. Surf. Eng. 50 (2017) 17-23. https://doi.org/10.5695/JKISE.2017.50.1.17
  10. Cheolgi Park, Sungmo Moon, Inmo Cheong and Daesoo Yun, Effect of AC current density on the PEO film formation of Al6061 alloy, Kor. Inst. Surf. Eng. 50 (2017) 138-144.
  11. Jung-Hyung Lee, Seong-Jong Kim, Influences of Potassium Fluoride (KF) Addition on the Surface Characteristics in Plasma Electrolytic Oxidation of Marine Grade Al Alloy, Kor. Inst. Surf. Eng. 49 (2016) 280-285. https://doi.org/10.5695/JKISE.2016.49.3.280
  12. Jung-Hyung Lee, Seong-Jong Kim, Characterization of Ceramic Oxide Layer Produced on Commercial Al Alloy by Plasma Electrolytic Oxidation in Various KOH Concentrations, Kor. Inst. Surf. Eng. 49 (2016) 119-124. https://doi.org/10.5695/JKISE.2016.49.2.119
  13. E. Matykina, R. Arrabal, A. Mohamed, P. Skeldon, G.E. Thompson, Plasma electrolytic oxidation of pre-anodized aluminium, Corrosion Science 51 (2009) 2897-2905. https://doi.org/10.1016/j.corsci.2009.08.004
  14. S. Moon, Y. Jeong, Generation mechanism of microdischarges during plasma electrolytic oxidation of Al in aqueous solutions, Corrosion Science 51 (2009) 1506-1512. https://doi.org/10.1016/j.corsci.2008.10.039
  15. Duyoung Kwon, Pung-Keun Song and Sungmo Moon, Formation Behavior and Properties of PEO Films on AZ91 Mg Alloy in 0.1 M NaOH + 0.05 M NaF Solution Containing Various Na2SiO3, Kor. Inst. Surf. Eng. 53 (2020) 59-66.
  16. Sungmo Moon, Juseok Kim, Effect of Na3PO4 Concentration on The Formation Behavior of PEO films on AZ31 Mg Alloy, Kor. Inst. Surf. Eng. 52 (2019) 265-274.
  17. SungmoMoon, Yeajin Kim, Cheolnam Yang, Effect of NaOH Concentration on the PEO Film Formation of AZ31 Magnesium Alloy in the Electrolyte Containing Carbonate and Silicate Ions, Kor. Inst. Surf. Eng. 50 (2017) 308-314.
  18. D. Kwon, S. Moon, Effects of NaOH Concentration on the Structure of PEO Films Formed on AZ31 Mg Alloy in PO43- and SiO32- Containing Aqueous Solution, Kor. Inst. Surf. Eng. 49 (2016) 46-53. https://doi.org/10.5695/JKISE.2016.49.1.46
  19. S. Moon, D. Kwon, Anodic Oxide Films Formed on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation Method in Electrolytes Containing Various NaF Concentrations, Kor. Inst. Surf. Eng. 49 (2016) 225-230. https://doi.org/10.5695/JKISE.2016.49.3.225
  20. S. Moon, Yeajin Kim, Anodic oxidation behavior of AZ31 magnesium alloy in aqueous electrolyte containing various Na2CO3 concentrations, Kor. Inst. Surf. Eng. 49 (2016) 331-338. https://doi.org/10.5695/JKISE.2016.49.4.331
  21. S. Moon, C. Yang, S. Na, Effects of Hydroxide and Silicate ions on the Plasma Electrolytic Oxidation of AZ31 Mg Alloy, Kor. Inst. Surf. Eng. 47(2014) 147-154. https://doi.org/10.5695/JKISE.2014.47.4.147
  22. X. Lu, M. Mohedano, C. Blawert, E. Matykina, R. Arrabal, K. U. Kainer, M. L. Zheludkevich, Plasma electrolytic oxidation coatings with particle additions - A review, Surface and Coatings Technology 307 (2016) 1165-1182. https://doi.org/10.1016/j.surfcoat.2016.08.055