污染物MgCl2与合金元素Mo对不锈钢大气腐蚀行为影响机制的研究

The project reviews special corrosion rules of stainless steel in salt lake atmosphere. Based on the corrosion process of stainless steel, with the help of AFM, SEM and XPS, an in-situ but non-consecutive research will be carried out to firstly investigate the initial corrosion evolution of passive film on stainless steel, revealing the initial corrosion mechanism, and then study the evolutional law of corrosion products, elucidating the influence of corrosion products on the subsequent corrosion behavior of stainless steel. Meanwhile, the pit initiation and development processes of stainless steel under thin electrolyte film will also be investigated by electrochemical noise. These results will clarify the influence of environmental factor (MgCl2) and alloying element (Mo) on the corrosion behavior of stainless steel in a simulated atmosphere. Finally, the atmospheric corrosion model of stainless steel will be established. The research will make the study on atmospheric corrosion of stainless steel go further, and also provide theoretical guidance for the reasonable selection of construction of various facilities in western salt lake area.

本项目着眼于不锈钢在盐湖大气环境下的特殊腐蚀规律。以不锈钢腐蚀历程为脉络，利用原子力显微镜、扫描电镜（SEM）和XPS物相分析方法，首先实现原位、非连续观测和分析不锈钢表面钝化膜的初期腐蚀动态过程，明确不锈钢的初期腐蚀机制，而后掌握后期腐蚀产物的演化规律，揭示腐蚀产物对不锈钢后续腐蚀行为的影响机制；同时，利用电化学噪声技术及薄液膜环境着重研究模拟大气环境下不锈钢的点蚀孕育和发展过程。综合所有实验结果全面剖析模拟大气环境下环境因素(MgCl2)和合金元素(Mo)对不锈钢腐蚀行为的影响机制。最终建立不锈钢在盐湖大气环境中的腐蚀理论模型，将不锈钢大气腐蚀研究进一步推向深入，也可为西部盐湖地区各种设施建设如何合理选材提供理论指导。

根据实际盐湖大气环境特点设置试验参数，建立合适的模拟盐湖大气环境体系;利用传统失重、XPS、XRD和电化学测试等分析方法探究了304不锈钢在实际盐湖大气和模拟盐湖大气环境中的腐蚀行为特点;阐明了304不锈钢在实际盐湖大气中的腐蚀演化规律包括腐蚀形貌及腐蚀产物成分;揭示了污染物MgCl2对304不锈钢腐蚀机制的影响;建立不锈钢在盐湖大气环境中的腐蚀模型，为304不锈钢在青海盐湖地区的应用提供理论指导。