局部腐蚀电池中的扩散电位差

中国腐蚀与防护学报

1984, Vol. 4

Issue (2): 101-107

研究报告

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局部腐蚀电池中的扩散电位差

杜元龙

中国科学院金属腐蚀与防护研究所

DIFFUSION POTENTIAL DIFFERENCE IN LOCALIZED CORROSION CELL

Du Yuanlong(Institute of Metallic Corrosion and Protection; Academia Sinica)

全文: PDF(619 KB)

摘要: 无论哪种类型的局部腐蚀电池,在它们的阴极和“闭塞”阳极之间总有一个电位差。本文作者从理论上分析了上述电位差的一个重要组成部份—扩散电位差—的产生和它的本质,模拟局部腐蚀电池在结构上的一些主要特征,设计了可用于测量扩散电位差的实验装置,研究了铁与10~(-3)NNaCl溶液构成的局部腐蚀体系的扩散电位差。结果表明,随着局部腐蚀的逐渐发展,“闭塞”阳极液中FeCl_2浓度逐渐增加,它与本底溶液之间的扩散电位差与FeCl_2浓度(N)的对数呈线性关系。在20℃时,其斜率为+32mV,和根据Planck-Henderson方程式计算的理论值完全一致。结果证明,在局部腐蚀电池阴、阳极之间的扩散电位差是所有有关离子的淌度的差或扩散系数的差所引起的非平衡电位差。

Abstract：No matter what kind of localized corrosion cell it is, there is always a potential difference between its cathode and occluded anode. There are actual ly a few components in the potential difference between the cathode and the anode in localized corrosion cell. The character of one of its important components-diffusion potential difference—is analyzed theoretically. For measuring its value, a device is designed to simulate the main structural characteristics of the cell. For the localized corrosion system of iron in 10~(-3)N NaCl solution, along with the propagation of the localized corrosion, the concentration of FeCl_2 in anolyte will increase gradually. In such a case, this diffusion potential difference is linear with the logarithm of the concentration of FeCl_2 in anolyte. At 20℃, it will increase 32mV for each ten-fold of the increase of the concentration of FeCl_2. When the anolyte changes to saturated solution in FeCl_2, it equals 125±2 mV. The results measured experimentally are well coincided with the values calculated theoretically based on the Planck-Henderson's equation. The results prove that, this diffusion potential difference is a nonequilibrium potential difference caused by the difference of the ionic mobilities or the difference of the diffusion coefficients of all ions of both the occluded anolyte and the bulk solution. For Cl~- containing solution, it does not equal the potential difference between two equilibrium electrodes reversible to Cl~- in the anolyte and in the bulk solution respectively.

收稿日期: 1984-04-25

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引用本文:

杜元龙. 局部腐蚀电池中的扩散电位差[J]. 中国腐蚀与防护学报, 1984, 4(2): 101-107.
. DIFFUSION POTENTIAL DIFFERENCE IN LOCALIZED CORROSION CELL. J Chin Soc Corr Pro, 1984, 4(2): 101-107.

链接本文:

https://www.jcscp.org/CN/ 或 https://www.jcscp.org/CN/Y1984/V4/I2/101

[1] Pickering, H.W.; Frankenthal, R.P., J. Electrochem. Soc., 119, 1297(1972)
[2] pourbaix, M., CEBELCOR, Rapports Techniques, 111, RT.166(1969)
[3] Alkire, R.; Ernsberger, D., Damon, D., J. Electrochem.Soc., 123, 458(1976)
[4] Schwenk, W., Corrosion, 20, 129t(1964)
[5] Nisancioglu, K.; Holtan, H., Electrochim. Acta, 23, 3, 251～3 (1978)
[6] Galvele, J.R., J. Electrochem. Soc., 123, 464(1976)
[7] Pourbaix, M., Occlusion corrosion cells and crack tip chemistry. Lecture delivered at the NATO Advanced Research Institute ATOMISTICS OF FRACTURE, 22～31 May, 1981, San Sebastiao(Corsica)
[8] Bockris, J. O'M.; Reddy, A. K. N., Modern Electrochemistry. 1, p.408, Plenum Press, New York(1970)
[9] Planck, M., Ann. Physik.,39, 161(1890a); ibid., 40, 561(1890b); or cf. Bockris, J.O'M.; Fredlein, R. A., "A Workbook of Electrochemistry", p.38～40, Plenum Press, New York-London(1973)
[10] Henderson, P., Z. Physik.Chem, 59, 118(1907) ; ibid., 63, 325(1908)
[11] Sathler, L.; Van Muylder, J.; Winand, R.; Pourbaix, M., Proce. edings of the 7th International Congress on Metallic Corrosion, 705(1978)
[12] Parsons, R., Handbook of Electrochemical Constants, (1959)
[13] Sathler, L., Contribution a l'etude du comportment electrochimique du fer en presence de solutions de chlorure ferreux, en liaison avec corrosion localisee. These de Doctorat, (1978) , Universite Libre de Bruxelles, p.164
[14] International Critical Tables. 6, p.309

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