船用钢板材料在淡水环境中初期腐蚀行为

目的研究船用钢板材料在长江淡水环境中的初期腐蚀行为。方法运用形貌分析、腐蚀质量损失、XRD、开路电位、极化曲线等方法研究Q235B和CCSA两种船用钢板材料在室外长江淡水环境中不同暴露方式(水面大气、半浸、全浸)及不同浸泡时间(0.5,1 a)腐蚀行为;室内长江淡水环境不同暴露方式(半浸、全浸)浸泡768 h内的腐蚀行为;室内长江淡水环境全浸泡下在不同时间(0~14 d)的电化学腐蚀行为。结果两种船用钢板材料在武汉长江淡水中腐蚀严重,半浸泡环境下腐蚀速率最大,达到100μm/a,水面区大气腐蚀速率最小,腐蚀速率为30μm/a左右,全浸区腐蚀速率为80μm/a左右,1 a和0.5 a的腐蚀速率相近,CCSA耐蚀性优于Q235B。室内长江淡水浸泡环境下两种船用钢板材料腐蚀电位随时间而降低,2d后趋于稳定;半浸泡环境下腐蚀速率大于全浸区;极化曲线说明浸泡2 d后,腐蚀速率降低且趋于稳定。结论 CCSA耐蚀性优于Q235B,半浸泡环境下腐蚀最严重,其次为全浸区,水面大气环境腐蚀最小。

Initial Corrosion Behaviors of Ship Steel Plate in Fresh Water Environment

Objective To study initial corrosion behaviors of ship steel plate material in fresh water environment of the Yangtze River.Methods Several methods including morphology analysis, weight loss analysis, XRD, open circuit poten-tial and polarization curves were used to study corrosion behaviors of Q235B and CCSA in different exposure modes (surface water, semi immersion, full immersion) and different soaking time (0.5a, 1a) in outdoor fresh water environment of the Yangtze River; corrosion behaviors in different exposure conditions (semi immersion and full immersion) in indoor fresh water environment of the Yangtze River in 768h; electrochemical corrosion behaviors of indoor fresh water envi-ronment at different times (0-14 d).Results Two kinds of ship steel plate materials suffered from serious corrosions in the Wuhan Section of the Yangtze River. The corrosion rate in the semi immersion environment was the largest, which was up to100μm/a; the corrosion rate in the water surface area was the smallest, which was about 30μm/a and the whole immer-sion zone was about 80μm/a; the corrosion resistance of CCSA was better than that of Q235B and the corrosion rate was similar between 1 and 0.5 years. The corrosion potential of two kinds of marine steel plates in the fresh water immersion environment of Yangtze River decreased with time, and tended to be stable 2 days later. The corrosion rate in the semi immersion environment was greater than that of the full immersion zone. The polarization curves showed that after 2 days of immersion, the corrosion rate decreased and tended to be stable.Conclusion The corrosion resistance of CCSA is better than that of Q235B.The corrosion is the most serious in the semi immersion environment, followed by the total immersion zone, and the minimum environmental corrosion in the water surface.