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Applications of Micro-Droplet Cell to Study of Localized Corrosion Resistance of Stainless Steels

스테인리스강의 국부부식 저항성 연구에 미세방울셀의 응용

  • Published : 2006.05.01

Abstract

Micro-droplet cell with free droplet as a micro-electrochemical technique has been limited to apply to electrochemical systems with high wetting properties such as an acidic solution and low grade stainless steels(Type 316L). By loading negative pressure to a droplet, control of droplet size, and use of hydrophobic gasket, the cell is modified to be allowed to use for electrochemical systems with high wetting properties. For giving the reliability of new cell, studies on local corrosion were conducted for three different systems-an acidic chloride solution and high chromium ferritic stainless steel, the other acidic chloride solution and type 316, and a neutral chloride solution and type 316. stainless steel. Firstly, the modified micro-droplet cell allows the anodic polarization curves in an acidic chloride solution to show the fact that the local corrosion of high chromium stainless steel near the $\alpha/\sigma$ interface is due to the Cr depleted zone. Secondly, the local anodic polarization test of type 316 L in the other acidic chloride solution can be successfully conducted in the cell. Furthermore, the local polarization curves help elucidating the corrosion of type 316 with $\delta-ferrite$ phase. Finally, the polarization curves of type 316 L in a neutral chloride solution indicates that the factor affecting the pitting corrosion resistance was inclusions rather than $\delta-ferrite$.

마이크로 전기화학 실험법인 비접촉식 미세방울셀이 산 용액에 노출된 저 크롬이 함유된 스테인리스강(STS 316)과 같이 젖음성이 높은 전기화학계에 사용되는데 어려움이 있었다. 음압의 인가, 방울의 크기 제어 그리고 소수성의 개스킷의 사용은 높은 젖음성을 지닌 표면에서 비접촉식 미세방울셀의 적용을 가능하게 하였다. 개선된 미세방울셀의 신뢰성을 확인하고자 3종류의 다른 계-산성염화용액과 고 크롬 페라이트 스테인리스강, 산성염화용액과 STS 316 그리고 중성염화용액과 STS 316-에 대하여 개선된 미세방울셀로 국부부식 연구를 수행하였다. 첫째 산성용액에서 고 크롬강의 양극 분극 결과는 $\alpha/\sigma$ 계면 근처에서 국부부식이 크롬 고갈층에 의한 것임을 보여주었다. 둘째 산성용액에서 STS316의 양극 분극실험이 개선된 미세방울셀에서 성공적으로 수행됨을 확인할 수 있었다. 특히, 미세방울셀에서 얻어진 국부 양극 분극곡선을 통해 STS316의 내식성에 미치는 $\delta$-라이트 영향을 밝힐 수 있었다. 마지막으로 중성염화 용액에서 STS316의 양극 분극곡선은 핏팅 저항성이 $\delta$-페라이트보다 개재물에 의존됨을 보여주었다.

Keywords

References

  1. C. J. Park, M. M. Lohrengel, T. Harnelman, M. Pilaski, and H. S. Kwon, 'Grain-dependent passivation of surfaces of polycrystalline zinc' Electrochimica Acta, 47, 21, 3395-3399 (2002) https://doi.org/10.1016/S0013-4686(02)00221-9
  2. C. J. Park, H.-S. Kwon, and M. M. Lohrengel, 'Micro-electrochemical polarization study on 25% Cr duplex stainless steel' Materials Sci. and Eng., 372, 180 (2004) https://doi.org/10.1016/j.msea.2003.12.013
  3. R. A. Perren, T. Suter, P. J. Uggowitzer, L. Weber, R. Magdowski, H. bohni, and M. O. Speidel, 'Corrosion resistance of super duplex stainless steels in the chloride ion containing environments: investigations by means of a new microelectrochemical method I. Precipitates-free states' Corros. Sci., 43, 707 (2001) https://doi.org/10.1016/S0010-938X(00)00087-1
  4. R. A. Perren, T. Suter, P. J. Uggowitzer, L. Weber, R. Magdowski, H. Sohni, and M.O. Speidel, 'Corrosion resistance of super duplex stainless steels in the chloride ion containing environments: investigations by means of a new microelectrochemical method II. Influence of precipitates' Corros. Sci., 43, 727 (2001) https://doi.org/10.1016/S0010-938X(00)00071-8
  5. H. Ha and H. Kwon, 'Effects of $Cr_2$N on Pitting Corrosion of High Nitrogen Stainless Steel Investigated by Micro-droplet Cell' 208th ECS Meeting, no. 367 October 16-21, 2005, Los Angeles, California
  6. T. Suter and H. Bohni, 'A new electrochemical method to study pit initiation on stainless steels' Electrochim. Acta, 42, 3275 (1997)
  7. T. Suter, H. Bohni, 'Microelectrodes for corrosion studies in rnicrosystem' Electrochim. Acta, 47, 191 (2001) https://doi.org/10.1016/S0013-4686(01)00580-1
  8. T. Suter, E. G. Webb, H. Bohni, and R. C. Alkire, 'Pit Initiation on Stainless Steels in 1 M NaCI With and Without Mechanical Stress' J. ElectroChem. Soc., 148, B186 (2001) https://doi.org/10.1149/1.1360205
  9. T. Suter, 'Mikroclektronische Untersuchungen bei austenitischen 'rostfreien' Stahlen' Ph. D. Thesis No. 11962, ETH Zurich, Zurich, Swiss (1997)
  10. M. M. Lohrengel, A. Moehring, and M. Pilaski, 'Capillary-based droplet cells: limits and new aspects' Electrochimi. Acta, 47, 137 (2001) https://doi.org/10.1016/S0013-4686(01)00570-9
  11. R. C. Alkire and K. P. Wong, 'The corrosion of single pits on stainless steel in acidic chloride solution' Corros. Sci., 28, 411 (1988)
  12. W. Brandl, 'Practicability of electrochemical measurements in microareas' Electrochim. Acta, 37, 2263 (1992)
  13. M. M. Lohrengel, A. Moehring, and M. Pilaski, 'Electrochemical surface analysis with the scanning droplet cell' Fresenius J. Anal. Chem., 367, 334 (2000)
  14. H. Kim, 'Effect of nickel and tungsten on dissimilar material crevice corrosion resistance of super ferritic stainless steels' Corrosion/2002, paper no. 02208, April 7-11, 2002, National Association of Corrosion Engineers, Houston, Texas
  15. P. E. Manning, C. E. Lyman, and D. J. Duquette, 'A STEM examination of the localized corrosion behavior of a duplex stainless steel' Corrosion, 36, 246 (1980)
  16. A. Garner, 'Chloride pitting and crevice corrosion of austenitic stainless steel weld metal' Corrosion/78, paper no. 78020, March 6-10, 1978, National Association of Corrosion Engineers, Houston, Texas
  17. S.- Y. Kim, 'Effects of secondary phases on the corrosion resistance of stainless steels using micro-droplet cell' MS. Thesis, Hongik Uni., Jochiwon, Korea (2006)
  18. K. Ososawa and H.-J. Engell, 'The anodic polarization curves of iron-nickel-chromium alloys' Corros. Sci., 6, 389 (1966) https://doi.org/10.1016/S0010-938X(66)80022-7
  19. M. S. El-Basiouny and S. Haruyama, 'The polarization behaviour of Fe-Cr alloys in acidic sulphate solutions in the active region' Corros. Sci., 16, 529 (1976) https://doi.org/10.1016/S0010-938X(76)80030-3
  20. S. Haupt and H.-H. Strehblow, 'A combined surface analytical and electrochemical study of the formation of passive layers on FeCr alloys in 0.5 M $H_2SO_4$' Corros. Sci., 37, 43 (1995) https://doi.org/10.1016/0010-938X(94)00104-E
  21. R. C. Newman, 'The dissolution and passivation kinetics of stainless alloys containing molybdenum-1. Coulometric studies of Fe-Cr and Fe-Cr-Mo alloys' Corros. Sci., 25, 331 (1985) https://doi.org/10.1016/0010-938X(85)90111-8
  22. I. Olefjord and B. O. Elfstrom, 'Composition of the surface during passivation of stainless steels' Corrosion, 38, 46 (1982)
  23. J. N. Wanklyn, 'The role of molybdenum in the crevice corrosion of stainless steels' Corros. Sci., 21, 211 (1981)
  24. C. Lu and C. R. Clayton, 'Evidence for a bipolar mechanism of passivity in Mo bearing stainless steel' J. Electrochem. Soc., 132, 2517 (1985) https://doi.org/10.1149/1.2114001
  25. S. K. Ryu, Y. H. Kim, and Y. D. Lee, 'Microbially Influenced Corrosion in Type 304 Stainless Steel Buried Pipe' J. Corros. Sci. of Korea, 25, 349 (1996)
  26. H. Kim and Y. D. Lee, 'Effect of microalloy elements on corrosion resistance of high-chrominum containing stainless steels in chloride solutions' Corrosion, 57, 547 (2001) https://doi.org/10.5006/1.3290381