超高强海工钢EH890在模拟海洋环境下的腐蚀行为研究

Study on Corrosion Behavior of Ultra-High Strength Marine Engineering Steel EH890 in Simulated Marine Environment

为满足海洋工程用钢的发展需求,设计开发了高强高耐蚀含Cu海工钢EH890。通过动电位极化曲线与电化学阻抗谱测量,结合X射线光电子能谱分析(XPS)、扫描电镜(SEM)、X射线衍射(XRD)等分析手段,对比分析了EH890和EH460在3.5%NaCl溶液中腐蚀行为,并对腐蚀形貌与腐蚀产物物相进行讨论。结果表明:在3.5%NaCl溶液中,同EH460钢相比,EH890钢的腐蚀电流密度降低了20%,电荷转移电阻R_(t)提高了1.6倍,EH890具有更好的耐腐蚀性;在3.5%NaCl溶液中浸泡7 d后,EH890试样呈现均匀腐蚀特征,而EH460表现为不均匀腐蚀,表面锈层局部发生龟裂。在EH890锈层中生成的CuFeO_(2)和NiFe_(2)O_(4)提高了腐蚀初期锈层的致密性,抑制了腐蚀的进程,从而提高了EH890在3.5%NaCl溶液中的耐腐蚀性。

In order to meet the development needs of steel for marine engineering, the high strength and high corrosion resistance marine engineering steel EH890 containing Cu was designed and developed. The corrosion behavior of EH890 and EH460 in 3.5% NaCl solution was compared and analyzed by potentiodynamic polarization curve, electrochemical impedance spectroscopy, X-ray photoelectric analysis(XPS), scanning electron microscope(SEM) and X-ray diffraction(XRD), and the corrosion morphology and composition of corrosion products were discussed. Results showed that compared with EH460 steel, the corrosion current density of EH890 steel was reduced by 20% in 3.5% NaCl solution, and the charge transfer resistance R_(t) increased by 1.6 times, indicating that EH890 had better corrosion resistance. After soaking in 3.5% NaCl solution for 7 d, the EH890 sample exhibited uniform corrosion characteristics, while EH460 exhibits uneven corrosion, with localized cracking of the surface rust layer. Furthermore, CuFeO_(2) and NiFe_(2)O_(4) formed in the rust layer of EH890 improved the compactness of the rust layer at the initial stage of corrosion, inhibited the corrosion process, and improved the corrosion resistance of EH890 in 3.5% NaCl solution.