Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
권호 표지
DOI QR코드

DOI QR Code

Correlation between crystalline phase and corrosion resistance of Mg alloy with different PEO conditions. I. Crystalline phase

Mg 합금의 PEO 공정 조건에 따른 산화피막 결정상과 내부식성에 대한 연구 I. 결정상

  • Received : 2018.02.23
  • Accepted : 2018.03.22
  • Published : 2018.04.30
Download PDF
⟨ Previous Next ⟩

Abstract

To increase corrosion resistance of Mg alloy, AZ31 and AZ91 were PEO treated with different applied voltage and time conditions. We used Na-P and Na-Si system electrolyte. Crystalline phase and morphology were investigated. MgO was Most common crystal phase and vitreous phase could be found. Crystalline phase of $Na_{3.59}Mg_{2.71}(PO_4)_3$ and $Mg_2SiO_4$ also could be found. Porosity of oxidized surface tends to decrease with increasing PEO applied voltage, treat time and concentration of electrolyte, after then, size of pore increased and total number of pore decreased, distinctly.

내부식성이 약해서 응용이 제한되고 있는 Mg 합금 AZ31과 AZ91의 내부식성을 향상시키기 위하여 Na-P 및 Na-Si 전해액을 사용하여 공정조건에 따라 PEO 처리를 하여 표면 피막의 결정상과 morphology를 관찰하였다. PEO 처리한 표면 산화피막에서 가장 흔히 발견되는 결정상은 MgO이며 비정질상의 존재도 알 수 있었다. 전해액에서부터 비롯된 Na, P 및 Si 성분이 산화피막의 형성에 첨가되어 $Na_{3.59}Mg_{2.71}(PO_4)_3$ 상과 $Mg_2SiO_4$ 결정상이 관찰되었다. 산화표면은 PEO 처리 전압, 전해질 농도, 처리 시간에 따라서 기공율이 감소하다가, 이후 기공율과 기공의 크기가 증가하는 경향을 관찰할 수 있었다.

Keywords

References

  1. B.L. Mordike and T. Ebert, "Magnesium: Propertiesapplications-potential", Mat. Sci. and Eng. A302 (2001) 37.
  2. G.L. Song and A. Atrens, "Corrosion mechanisms of magnesium alloys", Adv. Eng. Mat. 1 (1999) 11. https://doi.org/10.1002/(SICI)1527-2648(199909)1:1<11::AID-ADEM11>3.0.CO;2-N
  3. H.F. Guo and M.Z. An, "Effect of surfactants on surface morphology of ceramic coatings fabricated on magnesium alloys by micro-arc oxidation", Thin Solid Films 500 (2006) 186. https://doi.org/10.1016/j.tsf.2005.11.045
  4. Y. Ma, X. Nie, D.O. Northwood and H. Hu, "Systematic study of the electrolytic plasma oxidation process on a Mg alloy for corrosion protection", Thin Solid Films 494 (2006) 296. https://doi.org/10.1016/j.tsf.2005.08.156
  5. A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews and S.J. Dowey, "Plasma electrolysis for surface engineering", Surface and Coating Technol. 122 (1999) 73. https://doi.org/10.1016/S0257-8972(99)00441-7
  6. B.Y. Kim, J.H. Ham, D.Y. Lee, M.-S. Jeon, Y.-N. Kim, K.-Y. Kim, J.-W. Choi, S.Y. Kim and K.Y. Kim, "Effect of process conditions on crystal structure of Al PEO coating. I. Unipolar and coating time", J. Korean Cryst. Growth Cryst. Technol. 24 (2014) 59. https://doi.org/10.6111/JKCGCT.2014.24.2.059
  7. B.Y. Kim, J.H. Ham, D.Y. Lee, M.-S. Jeon, Y.-N. Kim, K.-Y. Kim, J.-W. Choi, S.Y. Kim and K.Y. Kim, "Effect of process conditions on crystal structure of Al PEO coating. II. Bipolar and electrolyte", J. Korean Cryst. Growth Cryst. Technol. 24 (2014) 65. https://doi.org/10.6111/JKCGCT.2014.24.2.065
  8. Y. Gao, A. Yerokhin and A. Matthews, "DC plasma electrolytic oxidation of biodegradable cp-Mg: In-vitro corrosion studies", Surface & Coatings Technol. 234 (2013) 132. https://doi.org/10.1016/j.surfcoat.2012.11.035
  9. G. Lv, H. Chen, X. Wang, H. Pang, G. Zhang, B. Zou, H. Lee and S. Yang, "Effect of additives on structure and corrosion resistance of plasma electrolytic oxidation coatings on AZ91D magnesium alloy in phosphate based electrolyte", Surface & Coatings Technol. 205 (2010) S36. https://doi.org/10.1016/j.surfcoat.2010.03.035
  10. S. Wang, Y. Xia, L. Liu and N. Si, "Preparation and performance of MAO coatings obtained on AZ91D Mg alloy under unipolar and bipolar modes in a novel dual electrolyte", Ceramics International 40 (2014) 93. https://doi.org/10.1016/j.ceramint.2013.05.108
  11. H.M. Wang, Z.H. Chen and L.L. Li, "Corrosion resistance and microstructure characteristics of plasma electrolytic oxidation coatings formed on AZ31 magnesium alloy", Surface Eng. 26 (2010) 85.
  12. R. Arrabal, E. Matykina, F. Viejo, P. Skeldon and G.E Thompson, "Corrosion resistance of WE43 and AZ91D magnesium alloys with phosphate PEO coatings", Corrosion Sci. 50 (2008) 1744. https://doi.org/10.1016/j.corsci.2008.03.002
  13. Y. Mori, A. Koshi, J. Liao, H. Asoh and S. Ono, "Characteristics and corrosion resistance of plasma electrolytic oxidation coatings on AZ31B Mg alloy formed in phosphate - silicate mixture electrolytes", Corrosion Sci. 88 (2014) 254. https://doi.org/10.1016/j.corsci.2014.07.038
  14. Z.P. Yao, D.L. Wang, Q.X. Xia, Y.J. Zhang, Z.H. Jiang and F.P. Wang, "Effect of PEO power modes on structure and corrosion resistance of ceramic coatings on AZ91D Mg alloy", Surface Eng. 28 (2012) 6.
  15. R.O. Hussein, X. Nie and D.O. Northwood, "Influence of process parameters on electrolytic plasma discharging behavior and aluminum oxide coating microstructure", Surface and Coatings Technol. 205 (2010) 1659. https://doi.org/10.1016/j.surfcoat.2010.08.059
  16. H.F. Guo and M.Z. An, "Growth of ceramic coatings on AZ91D magnesium alloys by micro-arc oxidation in aluminate-fluoride solutions and evaluation of corrosion resistance", Appl. Surface Sci. 246 (2005) 229. https://doi.org/10.1016/j.apsusc.2004.11.031
  17. P.B. Srinivasan, J. Liang, C. Blawert, M. stormer and W. Dietzel, "Effect of current density on microstructure and corrosion behavior of plasma electrolytic oxidation treated AM50 magnesium alloy", Appl. Surface Sci. 255 (2009) 4212. https://doi.org/10.1016/j.apsusc.2008.11.008