Mo元素对货油舱下底板用船板钢耐腐蚀性能的影响

Effect of Element Mo on the Corrosion Resistance of Shipbuilding Steel for Inner Bottom Plate of Cargo Oil Tanks

在模拟油船货油舱下底板所处的腐蚀环境中进行了腐蚀试验,并利用电子探针和电化学分析等方法研究了Mo元素对货油舱下底板用船板钢耐腐蚀性能的影响。结果表明:Mo元素可细化组织,提高自腐蚀电位,促进Cu在锈层中富集,提高钢板在货油舱下底板环境中的腐蚀均匀性,抑制局部腐蚀,提高耐腐蚀性能;但Mo含量超过0.1%(质量分数)后,组织过分细化,由于整体表面反应自由能降低,耐腐蚀性能有所降低。

Corrosion experiments of shipbuilding steels were conducted in a simulated corrosion environment around inner bottom plate of cargo oil tank （COT）. Effect of Mo on the corrosion resistance was investigated by means of electron probe microanalysis and electrochemical analysis. The results indicate that with the addition of Mo, the overall corrosion resistance improved, particularly in terms of enhancing corrosion uniformity and inhibiting pitting corrosion. The reasons may be due to refining of mierostructure, increase of free corrosion potential and promotion of Cu enrichment in the passive film. However, when the mass fraction of Mo was more than 0. 1%, the microstructure was over refined, and the corrosion resistance declined due to a decrease of reaction free energy of overall surface.