热带海洋大气环境中EH36船板钢早期腐蚀行为研究

Early Corrosion Behavior of EH36 Ship Plate Steel in Tropical Marine Atmosphere

在高湿、高热、高盐度和强辐照的湛江海洋大气腐蚀试验站对EH36船板钢进行了15、30、90、180和360 d的暴露实验。通过腐蚀失重计算了不同暴露周期的腐蚀速率,采用SEM观察了锈层表面和截面的微观形貌,采用X射线衍射仪分析了锈层的组成成分,采用EDS分析了锈层中的元素分布,同时对暴露后的试样进行了极化曲线测试。结果表明:EH36船板钢的腐蚀速率先增大、后减小;暴露360 d后,Cr、Ni和Si扩散到锈层中,分布较为均匀,提高了钢的耐腐蚀性能;暴露180和360 d的锈层中均含有γ-FeOOH、β-FeOOH、Fe3O4和α-FeOOH,暴露360 d的锈层中α-FeOOH较多,β-FeOOH较少,锈层中α/γ=0.615,尚未形成稳定的保护性锈层。

The EH36 ship plate steel was exposed for 15,30,90,180 and 360 d respectively in the atmosphere with high humidity,high heat,high salinity and strong radiation at the Zhanjiang marine atmospheric corrosion test station situated in the south of China.The corrosion behavior of different exposure periods were characterized by means of corrosion weight loss method,polarization curve measurement,scanning electron microscopy with energy dispersive spectroscopy and X-ray diffractometer.The results show that the corrosion rate of EH36 ship plate steel increases first and then decreases.After exposure for 360 d,Cr,Ni and Si elements diffuse into and uniformly distribute in the rust scale,which then improves the corrosion resistance of the steel.After exposure for 180 and 360 d,the formed rust scales composed ofγ-FeOOH,β-FeOOH,Fe3 O4 andα-FeOOH.While the one corresponded to 360 d exposure has moreα-FeOOH and lessβ-FeOOH.In the rust scale of EH36 ship steel exposed for 360 d the ratio ofα/γ=0.615,however,a stable protective rust scale has not yet appeared by this time.