Cu-Ni-Sn合金体系油船内底板用耐蚀钢研究

Research on Cu-Ni-Sn alloy corrosion resistant steel for inner bottom plates of cargo oil tank

利用扫描电镜（SEM）、电化学、光电子能谱（XPS）、激光原位、透射电镜（TEM）等方法研究了Cu-Ni-Sn体系船体钢在强酸性氯离子环境下的腐蚀行为。结果表明,采用Cu-Ni-Sn的耐蚀合金设计可以显著提高船体钢在强酸性氯离子环境下的耐蚀性,并满足IMO标准的要求;Cu是提高钢耐蚀性的有效元素,其主要机理为其以再沉积颗粒（100-500 nm）的方式在钢的表面富集,降低了钢的溶解速度并抑制点蚀的形核;随着钢中Sn含量的增加,钢的耐蚀性进一步提高,Sn在钢的表面形成了致密的SnO2腐蚀产物保护膜,有效阻止了基体与腐蚀介质的相互作用,进一步抑制了钢的腐蚀。

Scanning electron microscope（SEM）,electrochemical workstation,X- ray photoelectron spectroscopy（XPS）,laser in situ and transmission electron microscope（TEM） were used to study the corrosion behavior of Cu-Ni-Sn hull steel in strongly acidic chloride media. The results indicate that using Cu-Ni-Sn corrosion resistant alloy design can greatly improve corrosion resistance of hull steel in strongly acidic chloride environment,which meets the requirement of IMO. Cu can effectively enhance corrosion resistance of steel. The addition of Cu decreases corrosion rate of steel and inhibits nucleation of pitting corrosion because of the re-deposition of copper on the surface of steel. With the increase of Sn added to steel,corrosion resistance has a further improvement. It is considered to be related to the compact SnO2 protecting film on the surface of steel,which efficiently prevents the interaction between matrix and corrosion medium,then decreases corrosion rate of steel in corrosion medium.