Passivity degradation of alloy 800 in simulated crevice chemistries

Abstract

Passivity degradation of Alloy 800 in simulated crevice chemistries was systematically investigated using cyclic polarization curve, electrochemical impedance spectroscopy(EIS), Mott-Schottky analysis, Auger electron spectroscopy(AES)and atomic absorption spectrometry(AAS). Cyclic polarization showed that the pitting potential in a thiosulfate solution was much lower than in either a chloride solution or a sulfate-chloride solution. Mott-Schottky results revealed that passive films showed n-type semiconductivity, and the presence of thiosulfate in chloride solution led to an increased donor density in the passive film. EIS spectra indicated that thiosulfate enhanced the film dissolution rate in chloride solutions. Moreover, thiosulfate enhanced the pitting propagation rate in chloride solution by stabilizing the metastable pits and forming sulfide within the pits.

Keywords

Alloy 800 / thiosulfate / passive film / localized corrosion

References

[1] Xia D H, Luo J L. Corrosion behavior of alloy 690 in simulated alkaline water chemistries containing sulfur at 300 °C [J]. Acta Physico-Chimica Sinica, 2015, 31(3): 467-475.

[2] Luo B, Xia D H. Characterization of pH effect on corrosion resistance of nuclear steam generator tubing alloy by in-situ scanning electrochemical microscopy[J]. Acta Physico-Chimica Sinica, 2014, 30(1): 59-66.

[3] Xia D H, Zhou C, Liu Y H, et al. Mechanical properties and corrosion resistance of SA508-4 low carbon alloy steel[J]. Electrochemistry, 2013, 81(4): 262-268.

[4] Grant I S, Andrews P J D. ABC of intensive care: Neurological support[J]. British Medical Journal, 1999, 319(7202): 110-113.

[5] Xia D H, Behnamian Y, Feng H N, et al. Semiconductivity conversion of alloy 800 in sulfate, thiosulfate, and chloride solutions[J]. Corrosion Science, 2014, 87: 265-277.

[6] Kuo H S, Chang H, Tsai W T. The corrosion behavior of AISI 310 stainless steel in thiosulfate ion containing saturated ammonium chloride solution[J]. Corrosion Science, 1999, 41(4): 669-684.

[7] Laycock N J. Effects of temperature and thiosulfate on chloride pitting of austenitic stainless steels[J]. Corrosion, 1999, 55(6): 590-595.

[8] Tsai W T, Sheu M J, Lee J T. The stress corrosion crack growth rate in sensitized alloy 600 in thiosulfate solution[J]. Corrosion Science, 1996, 38(1): 33-45.

[9] Bandy R, Roberge R, Newman R C. Low-temperature stress-corrosion cracking of Inconel-600 under 2 different conditions of sensitization[J]. Corrosion Science, 1983, 23(9): 995-1006.

[10] Haruna T, Shibata T, Toyota R. Initiation and propagation of stress corrosion cracks for type 304L stainless steel in chloride solutions containing thiosulfate[J]. Corrosion Science, 1997, 39(10/11): 1935-1947.

[11] Fang Z, Staehle R W. Effects of the valence of sulfur on passivation of alloys 600, 690, and 800 at 25 degrees C and 95 degrees C[J]. Corrosion, 1999, 55(4): 355-379.

[12] Yang W, Lu Z, Huang D, et al. Caustic stress corrosion cracking of nickel-rich, chromium-bearing alloys[J]. Corrosion Science, 2001, 43(5): 963-977.

[13] Xia D H, Zhu R K, Behnamian Y, et al. pH effect on sulfurinduced passivity degradation of alloy 800 in simulated crevice chemistries[J]. Journal of the Electrochemical Society, 2014, 161(4): C201-C214.

[14] Xia D H, Yang L X. A mechanistic study on semiconductivity conversion in different concentration ratios of sulfate to chloride[J]. Acta Physico-Chimica Sinica, 2014, 30(8): 1465-1473.

[15] Staehle R W, Gorman J A. Quantitative assessment of submodes of stress corrosion cracking on the secondary side of steam generator tubing in pressurized water reactors: Part 1[J]. Corrosion, 2003, 59(11): 931-994.

[16] Li F, An M, Liu G, et al. Effects of sulfidation of passive film in the presence of SRB on the pitting corrosion behaviors of stainless steels[J]. Materials Chemistry and Physics, 2009, 113(2/3): 971-976.

[17] Staehle R W, Gorman J A. Quantitative assessment of submodes of stress corrosion cracking on the secondary side of steam generator tubing in pressurized water reactors: Part 3[J]. Corrosion, 2004, 60(2): 115-180.

[18] Xia D H, Song S Z, Wang J H, et al. Fast evaluation of degradation degree of organic coatings by analyzing electrochemical impedance spectroscopy data[J]. Transactions of Tianjin University, 2012, 18(1): 15-20.

[19] Shi J B, Xia D H, Wang J H, et al. Degradation process of coated tinplate by phase space reconstruction theory[J]. Transactions of Tianjin University, 2013, 19(2): 92-97.

[20] Macdonald D D, Sharifi-Asl S. Volt equivalent diagrams as a means of displaying the electrochemical thermodynamics of the sulfur-water system[J]. Corrosion Science, 2014, 81: 102-109.

[21] Senanayake G. Kinetic model for anodic oxidation of gold in thiosulfate media based on the adsorption of MS₂O₃-ionpair[J]. Hydrometallurgy, 2005, 76(3/4): 233-238.

[22] Zhang Y, Urquidi-Macdonald M, Engelhardt G R, et al. Development of localized corrosion damage on low pressure turbine disks and blades: I. Passivity[J]. Electrochimica Acta, 2012, 69: 1-11.

[23] Zhang Y, Urquidi-Macdonald M, Engelhardt G R, et al. Development of localized corrosion damage on low pressure turbine disks and blades: II. Passivity breakdown[J]. Electrochimica Acta, 2012, 69: 12-18.

[24] Zeng Y M, Luo J L, Norton P R. A study of semiconducting properties of hydrogen containing passive films[J]. Thin Solid Films, 2004, 460(1/2): 116-124.

[25] Zeng Y M, Luo J L, Norton P R. New interpretation of the effect of hydrogen on the ion distributions and structure of passive films on microalloyed steel[J]. Journal of the Electrochemical Society, 2004, 151(6): B291-B298.

[26] Xia D H, Song S Z, Zhu R K, et al. A mechanistic study on thiosulfate-enhanced passivity degradation of alloy 800 in chloride solutions [J]. Electrochimica Acta, 2013, 111: 510-525.