DOI QR코드

DOI QR Code

Effect of process conditions on crystal structure of Al PEO coating. I. Unipolar pulse and coating time

알루미늄 PEO 코팅의 결정상에 미치는 공정 조건에 대한 연구 I. Unipolar 펄스와 코팅시간

  • Received : 2014.03.31
  • Accepted : 2014.04.11
  • Published : 2014.04.30

Abstract

Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1050, were investigated. The electrolyte of PEO was $Na_2Si_2O_3$ and KOH. Unipolar pulse, $ 2000{\mu}sec$ with $400{\mu}sec+420V$ impulse, were applied for 2 min, 5 min, 15 min, and 30 min. ${\gamma}-Alumina$, as well as ${\alpha}-alumina$, was main crystal phase. ${\gamma}-Alumina$ was appeared in the beginning, then the amount of ${\alpha}-alumina$ was increased with time, but the amount of ${\gamma}-Alumina$ remained constant without any increasing. So, it is concluded that plasma gas produce ${\gamma}-Alumina$ at the first, and then ${\gamma}-Alumina$ transform ${\alpha}-alumina$ finally. During the transformation, high temperature of micro plasma gives transformation energy.

전해질로 $Na_2SiO_3$을 사용하여 A1050 알루미늄 판재를 pulse 폭 $ 2000{\mu}sec$, impulse 420 V, 400 ${\mu}$sec의 unipolar pulse로 플라즈마 전해 산화 코팅(plasma electrolytic oxidation coating)을 하여 산화 피막을 2, 5, 15, 30분에 따라 형성시킨 다음 산화피막을 분석하였다. 표면에 형성된 산화물의 결정상은 ${\alpha}-alumina$${\gamma}-Alumina$로서 시간에 따른 변화는 없었다. 반응 초반에는 ${\gamma}-Alumina$가 많이 생성되었지만 시간이 갈수록 ${\gamma}-Alumina$의 양에는 변화 없이 ${\alpha}-alumina$가 많이 생겨남을 알 수 있었다. 이런 결과는 micro plasma에 의해서 ${\gamma}-Alumina$가 우선 생성되고, 이후 계속되는 micro plasma의 열에 의해서 ${\alpha}-alumina$로의 전이가 일어나기 때문으로 판단된다.

Keywords

References

  1. A.L. Yerokhin, X. Nie, A. Leyland, A. Matthews and S.J. Dowey, "Plasma electrolysis for surface engineering", Surf. Coat. Technol. 122 (1999) 73. https://doi.org/10.1016/S0257-8972(99)00441-7
  2. X. Nie, A. Leyland, H.W. Song, A.L. Yerokhin, S.J. Dowey and A. Matthews, "Thickness effects on the mechanical properties of micro-arc discharge oxide coatings on aluminum alloys", Surf. Coat. Technol. 116 (1999) 1055.
  3. X. Nie, E.I. Meltis, J.C. Jiang, A. Leyland, A.L. Yerokin and A. Matthews, "Abrasive waer/corrosion properties and TEM analysis of $Al_2O_3$ coatings fabricated using plasma electrolysis", Surf. Coat. Technol. 149 (2002) 245. https://doi.org/10.1016/S0257-8972(01)01453-0
  4. A.L. Yerokin, A. Shatrov, V. Samsonov, P. Shahkov, A. Pilkington, A. Leyland and A. Matthews, "Oxide ceramic coatings on aluminium alloys produced by a pulsed bipolar plasma electrolytic oxidation process", Surf. Coat. Technol. 199 (2005) 150. https://doi.org/10.1016/j.surfcoat.2004.10.147
  5. H. Kalkanci and S.C. Kurnaz, "The effect of process parameters on mullite-based plasma electrolytic oxide coatings", Surf. Coat. Technol. 203 (2008) 15. https://doi.org/10.1016/j.surfcoat.2008.07.015
  6. F.-Y. Jin, K. Wang, M. Zhu, L.-R. Shen, J. Li, H.-H. Hong and P.K. Chu, "Infrared reflection by alumina films produced on aluminum alloy by plasma electrolytic oxidation", Mater. Chem. Phys. 114 (2009) 398. https://doi.org/10.1016/j.matchemphys.2008.09.060
  7. Y.-J. Oh, J.-I. Mun and J.-H. Kim, "Effect of alloying elements on microstucture and protective proties of $Al_2O_3$ coatings formed on aluminum alloy substrates by plasma electrolysis", Surf. Coat. Technol. 204 (2009) 141. https://doi.org/10.1016/j.surfcoat.2009.07.002
  8. G. Lv, W. Gu, H. Chen, W. Feng, M.L. Khosa, L. Li, E. Niu, G. Zhang and S.-Z. Yang, "Characteristic of ceramic coatings on aluminum by plasma electrolytic oxidation in silicate and phosphate electrolyte", Appl. Surf. Sci. 253 (2006) 2947. https://doi.org/10.1016/j.apsusc.2006.06.036
  9. W. Xue, Z. Deng, R. Chen, T. Zhang and H. Ma, "Microstructure and properties of ceramic coatings produced on 2024 aluminum alloy by microarc oxidation", J. Mater. Sci. 36 (2001) 2615. https://doi.org/10.1023/A:1017988024099
  10. J. Tian, Z. Luo, S. Qi and X. Sun, "Structure and antiwear behavior of micro-arc oxidized coatings on alluminum alloy", Surf. Coat. Technol. 154 (2002) 1. https://doi.org/10.1016/S0257-8972(01)01671-1
  11. E. Arslan, Y. Totik, E.E. Demirci, Y. Vangolu, A. Alsaran and I. Efeoglu, "High temperature wear behavior of aluminum oxide layers by AC micro arc oxidation", Surf. Coat. Technol. 204 (2009) 829. https://doi.org/10.1016/j.surfcoat.2009.09.057
  12. G. Sundararajan and L. Rama Krishna, "Mechanisms underlying the formation of thick alumina coatings through the MAO coating technology", Surf. Coat. Technol. 167 (2003) 269. https://doi.org/10.1016/S0257-8972(02)00918-0
  13. J.A. Curran and T.W. Clyne, "The thermal conductivity of plasma electrolytic oxide coatings on aluminum and magnesium", Surf. Coat. Technol. 197 (2005) 177. https://doi.org/10.1016/j.surfcoat.2005.01.039
  14. J.A. Curran and T.W. Clyne, "Thermo-physical properties of plasma electrolytic oxide coatings on aluminum", Surf. Coat. Technol. 199 (2005) 168. https://doi.org/10.1016/j.surfcoat.2004.09.037
  15. K. Wang, B.H. Koo, C.G. Lee, Y.J. Kim, S. Lee and E. Byon, "Effects of hybrid voltages on oxide formation on 6061 Al-alloys during plasma electrolytic oxidation", Chinese Journal of Aeronautics 22 (2009) 564. https://doi.org/10.1016/S1000-9361(08)60142-9
  16. K. Wang, B.H. Koo, C.G. Lee, Y.J. Kim, S. Lee and E. Byon, "Effects of electrolytes variation on formation of oxide layers of 6061 Al alloys by plasma electrolytic oxidation", Trans. Nonferrous Met. Soc. China 19 (2009) 866. https://doi.org/10.1016/S1003-6326(08)60366-0
  17. J.A. Curran, H. Kalkanci, Yu. Magurova and T.W. Clyne, "Mullite-rich plasma electrolytic oxide coatings for thermal barrier applications", Surf. Coat. Technol. 201 (2007) 8683. https://doi.org/10.1016/j.surfcoat.2006.06.050
  18. W. Gu, G. Lv, H. Chen, G.-L. Chen, W.-R. Feng and S.-Z. Yang, "Characterization of ceramic coatings produced by plasma electrolytic oxidation of aluminum alloy", Mater. Sci. Eng. A 447 (2007) 158. https://doi.org/10.1016/j.msea.2006.09.004
  19. B.-Y. Kim, D.Y. Lee, Y.-N. Kim, M.-S. Jeon, W.-S. You and K.-Y. Kim, "Effect of Al alloy composition on physical and crystallographical properties of plasma electrolytic oxidized coatings. I. Physical Properties of PEO layer", J. Kor. Ceram. Soc. 47 (2010) 256. https://doi.org/10.4191/KCERS.2010.47.3.256
  20. B.-Y. Kim, D.Y. Lee, M.C. Shin, H.-G. Shin, B.-K. Kim, S.Y. Kim and K.Y. Kim, "Effect of Al alloy composition on physical and crystallographical properties of plasma electrolytic oxidized coatings II. Crystallographic analysis of PEO layer", J. Kor. Ceram. Soc. 47 (2010) 283. https://doi.org/10.4191/KCERS.2010.47.4.283
  21. K.I. Kim, S.C. Choi, K.S. Han, K.T. Hwang and J.H. Kim, "Synthesis of high purity aluminum nitride nanopowder by RF induction thermal plasma", J. Korean Cryst. Growth Cryst. Technol. 24 (2014) 1. https://doi.org/10.6111/JKCGCT.2014.24.1.001
  22. Y.S. Park, I.H. Wui, W.S. Cho, J.H. Kim and K.T. Hwang, "Synthesis of bohemite powder from aluminum etching solution", J. Korean Cryst. Growth Cryst. Technol. 22 (2012) 286. https://doi.org/10.6111/JKCGCT.2012.22.6.286
  23. A.G. Rakoch, V.A. Bautin, N.A. Lebedeva and A.V. Kutuzov, "Model conceptions of metallic material microarc oxidation (MAO) process", New Achievements in Materials Science II France-Russia Seminar, Moscow, Russia, I. Coatings, Films and Surface Engineering (2005) I7.
  24. R.O. Hussein, X. Nie and D.O. Northwood, "Influence of process parameters on electrolytic plasma discharging behavior and aluminum oxide coating microstructure", Surf. Coat. Technol. 205 (2010) 1659. https://doi.org/10.1016/j.surfcoat.2010.08.059
  25. C. Ruberto, "Metastable alumina from theory : Bulk, surface, and growth of ${\kappa}-Al_2O_3$", Ph.D. Thesis, Dept. App. Phy., Chalmers Univ. Tech. and Gteborg Univ., Gteborg, Sweden (2001).

Cited by

  1. Effect of process conditions on crystal structure of Al PEO coating. II. Bipolar and electrolyte vol.24, pp.2, 2014, https://doi.org/10.6111/JKCGCT.2014.24.2.065