The corrosion behavior of a rusted 550 MPa grade offshore platform steel in Cl- containing environment was investigated. The results revealed that the corrosion process can be divided into initial stage in which corrosion rate increased with accumulation of corrosion products and later stage in which homogeneous and compact rust layer started to protect steel substrate out of corrosion mediums. On the contrary, structural analysis of rust layers by X-ray diffraction showed that α-FeOOH increased from 1. 3% to 3. 6% and the Fe3O4 increased from 1. 0% to 1. 5% while γ-FeOOH reduced slightly according to corrosion time increased from 30 cycles to 73 cycles. The results of electron probe microanalysis indicated that Cr concentrated mainly in the inner region of the rust, inner/outer interface especially, whereas Ni and Cu were uniformly distributed all over the rust after 73 corrosion cycles. According to electrochemical measurements, it was found that the corrosion rate of rusted steel reduced from 0. 61 mm/a after 45 cycles to 0. 34 mm/a after 85 cycles, 44. 3% reduction approximately, and Rrust values increased with increment of corrosion time. Therefore, formation of compact inner rust layer and enrichment of Cr are important to improve corrosion resistance of offshore platform steel.
Abstract
The corrosion behavior of a rusted 550 MPa grade offshore platform steel in Cl- containing environment was investigated. The results revealed that the corrosion process can be divided into initial stage in which corrosion rate increased with accumulation of corrosion products and later stage in which homogeneous and compact rust layer started to protect steel substrate out of corrosion mediums. On the contrary, structural analysis of rust layers by X-ray diffraction showed that α-FeOOH increased from 1. 3% to 3. 6% and the Fe3O4 increased from 1. 0% to 1. 5% while γ-FeOOH reduced slightly according to corrosion time increased from 30 cycles to 73 cycles. The results of electron probe microanalysis indicated that Cr concentrated mainly in the inner region of the rust, inner/outer interface especially, whereas Ni and Cu were uniformly distributed all over the rust after 73 corrosion cycles. According to electrochemical measurements, it was found that the corrosion rate of rusted steel reduced from 0. 61 mm/a after 45 cycles to 0. 34 mm/a after 85 cycles, 44. 3% reduction approximately, and Rrust values increased with increment of corrosion time. Therefore, formation of compact inner rust layer and enrichment of Cr are important to improve corrosion resistance of offshore platform steel.
关键词
海洋平台用钢 /
合金元素 /
腐蚀行为 /
锈层 /
电化学检测
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Key words
Offshore platform steel /
Alloying elements /
Corrosion behavior /
Rust layer /
Electrochemical measurements
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中图分类号：
TG174.3
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参考文献
1. H. Okada, Y. Hosoi and H. Naito. Corrosion, 1970; 26: 429
2. D.R. De Meybaum and E.S. Ayllon. Corrosion, 1980; 36: 345
3. I. Suzuki, Y. Hisamatsu and N. Masuka. Journal of the Electrochemical Society, 1980; 127: 345
4. H. Schmitter and H. Bohni. Journal of the Electrochemical Society, 1980; 127: 15
5. M. Stratman, K. Bohnenkamp and T. Ramchandran. Corrosion science, 1987; 27: 905
6. H.C. Shih, J.C. Oung, J.T. Hsu, J.Y. Wu and F.I. Wei. Materials Chemistry and Physics, 1994; 37: 230
7. T. Misawa, K, Asami, K. Hashimoto, S. Shimodaria. Corrosion Science, 1974; 14: 279
8. Hou W T, Liang C F. Corrosion, 2004; 60: 313
9. Wang J H, Wei F I, Chang Y S et al. Materials Chemistry and Physics, 1997; 47:1
10. Jia Guo, Shanwu Yang, Chengjia Shang, et al. Corrosion Science, 2008; 51: 247
11. Herve Antony, Stephane Perrin, et al. Electrochimica Acta, 2007; 52: 7754
12. Sei J Oh, Cook D C, Townsend H E. Corrosion Science, 1998; 41: 1687
13. M. Yamashita, H. Miyuki, H. Nagano, T. Misawa. Proceedings of 13th International Corrosion Congress, Melbourne, 1996: 258–264
14. M. Yamashita, H. Konishi, J. Mizuki, and H. Uchida. Nanostructure of Protective Rust Layer on Weathering Steel Exposed for 17 years examined by using Synchrotron Radiation, Cranada (Spain), 2003 (Int. Corrosion Council), p. topic 48
15. M. Yamashita, H. Konishi, and H. Uchida. Materials Transactions JIM, 2004; 45: 1920-1924
16. H. Miyuki, M. Yamashita, M. Fujiwara, T. Misawa. Zairyo to Kankyo/Corrosion Engineering, 1998; 47: 186–192
17. D.A Jones, principles and Prevention of Corrosion, 2nd ed. Prentice-Hall, NJ, 1996: 76
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脚注
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基金
国家高技术研究发展计划（863计划）
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