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| Corrosion Behavior of 304 Stainless Steel in the Sea Environment of South China Sea |
| Received:April 25, 2021 Revised:June 21, 2021 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/issn.1672-9242.2021.11.007 |
| KeyWord:marine corrosion South China Sea islands and reefs 304 stainless steel pitting corrosion |
| Author | Institution |
| DUAN Ti-gang |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
| PENG Wen-shan |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
| DING Kang-kang |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
| GUO Wei-min |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
| HOU Jian |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
| SUN Ming-xian |
State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute, Qingdao , China |
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| Abstract: |
| The corrosion behavior and law of 304 stainless steel material exposed to 0.5 a in the atmosphere, splash zone, tidal range and full immersion zone of the South China Sea are studied. Through the real sea environment adaptability test, the corrosion data of 304 stainless steel material in the South China Sea island reef environment is obtained. Through the observation of the corrosion morphology, the main corrosion form of 304 stainless steel is clear. Through electrochemical test and analysis, the corrosion resistance of 304 stainless steel is evaluated and its corrosion mechanism is clarified. The results show that the corrosion of 304 stainless steels is featured as the pitting corrosion in the reef environment of the South China Sea. The average corrosion rates of 304 stainless steels in the four zones are 0.8, 1.1, 1.3 and 3.2 μm/a, respectively, the average pitting depths are 13.57, 15.26, 18.62, 2.43 μm, while the maximum pitting corrosion depths are 28.85, 35.63, 32.93 and 40.25 μm, respectively. The test results of electrochemical impedance and Mott-Schottky curve show that the charge transfer of the four zone samples are 1.27×107, 8.76×106, 7.35×105 and 5.76×105 Ω.cm2, respectively. Additionally, the calculated carrier densities of specimens are 6.56×1022, 1.01×1023, 2.80×1023 and 4.15×1023 cm‒3, respectively. In the full immersion environment, the 304 stainless steel passivation film was the most damaged and the corrosion resistance decreased the most. For specimens exposed in the atmospheric zone and the splash zone, pitting corrosion is found and, weak crevice corrosion is formed at the fixed position. For those exposed in the tidal zone and the immersion zone, due to the adhesion of calcium-magnesium deposits and marine organism, an amount of corrosion microbatteries are formed featured with saturated-concentration chloride ions and low-concentration dissolved oxygen, more severe pitting corrosion occurs on the surface of 304 stainless steels and even the most severe for the immersion zone. |
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