300M超高强钢在中性盐雾环境中的腐蚀行为及机制

Corrosion behavior and mechanism of 300M ultra high strength steel in neutral salt spray environment

为了研究300M超高强钢在中性盐雾环境中的腐蚀行为及腐蚀机制,采用失重法,宏观、微观腐蚀形貌分析,三维表面轮廓分析及电化学分析的研究方法,来表征腐蚀实验现象并进行分析。结果表明:300M超高强钢在中性盐雾环境中的腐蚀产物为FeOOH、Fe2O3、Fe(OH)3和Fe3O4;腐蚀速率随着腐蚀时间逐渐降低,腐蚀后期(72 h)腐蚀速率降低50%;腐蚀初期以点蚀为主,点蚀坑通过横向扩展,逐渐发展为后期的均匀腐蚀,腐蚀表面形貌呈沟壑状;外腐蚀层对基体的保护能力很弱,Cr元素在锈层靠近基体的一侧偏聚使内腐蚀层具有一定的抗腐蚀性。

In order to study the corrosion behavior and mechanism of 300 M ultrahigh strength steel in neutral salt spray environment, the weight loss method, macroscopic and microscopic corrosion morphology analysis, three-dimensional surface contour analysis and electrochemical analysis methods were used to characterize and analysis the corrosion phenomenon. The results show that the corrosion products of 300 M ultrahigh strength steel in neutral salt spray environment are FeOOH, Fe2O3, Fe(OH)3 and Fe3O4;the corrosion rate decreases with the corrosion time, and decreases by 50% in the later stage of corrosion(72 h);in the initial stage of corrosion, pitting corrosion is dominant. The pitting pit is gradually expanded to the later uniform corrosion, and the surface morphology of the corrosion is gully. The outer corrosion layer has weak protection to the substrate. The Cr element is close to the substrate in the rust layer. One side of the segregation gives the inner corrosion layer a certain degree of corrosion resistance.