海洋冲刷腐蚀条件下高氮钢钝化膜稳定性及对冲蚀行为的影响机理

The erosion-corrosion behavior of high nitrogen austenitic stainless steel in simulated marine environment of different flow velocity, flow regime, sediment type and sediment content was investigated by using rotating cylinder apparatus and jet apparatus. The influence of these factors on corrosion behavior of HNS under erosion-corrosion condition was determined by using potentiodynamic polarization curves and electrochemical impedance spectroscopy technology, Mott-Schottky curves. The synergistic effect of corrosion and erosion was calculated. SEM and AFM were used to observe the Initiation and propagation path of cracks. Mott-Schottky analysis, crack initiation and propagation process in conjunction with PDM was performed to evaluate the stability of passive film formed in erosion-erosion condition. The influence of passive film stability on erosion corrosion mechanism of high nitrogen stainless steel in marine environment obtained. This will provide significant help in technical support and theoretical basis for our country in developing of marine resources and coastal defense security.

本项目以高氮奥氏体不锈钢为研究对象，采用动电位极化曲线、电化学阻抗谱、Mott-Schottky曲线等电化学测量技术，结合钝化膜的PDM模型以及冲蚀过程中裂纹的萌生和扩展过程，获得模拟海洋冲刷腐蚀过程的流速、流态、泥沙种类和泥沙含量等因素对高氮钢表面钝化膜的生长速度、缺陷浓度、稳定性及再钝化能力的影响，探索海洋冲蚀环境下高氮钢钝化膜稳定性及对冲蚀行为的影响机理，将为我国海洋资源的开发和海防安全提供技术支持和理论基础。

对以高氮钢为典型的材料在冲蚀条件下的临界现象进行了研究分析，并选择出合适的钝性材料冲蚀临界流速测试方法；从冲刷腐蚀临界流速研究的角度出发，研究了钝化膜在冲蚀过程中的表现，丰富了冲蚀机理；探讨了钝化膜性能的改变与材料耐冲蚀性能之间的关系，为耐冲蚀材料的设计提供了新的方向。与高氮钢在空蚀条件下的失重相比，冲蚀条件下高氮钢的交互作用分量所占总失重的比例更大，因此对流速较高的液/固双相流冲刷腐蚀条件下的选材需引起足够重视，在高速冲蚀条件下材料的选择仍将是今后冲刷腐蚀的研究重点。