Q345qDNH桥梁耐候钢在模拟工业大气环境中的腐蚀产物膜演变规律

Evolution Law of Corrosion Product Films of Q345qDNH Bridge Weathering Steel in Simulated Industrial Atmospheric Environment

采用干湿交替周期浸润腐蚀试验,研究了Q345qDNH桥梁耐候钢在模拟工业大气腐蚀环境中的腐蚀行为及其腐蚀产物膜演变规律,并与Q345B钢进行了比较。结果表明:在模拟工艺大气环境中,随着浸润周期的延长,Q345qDNH钢的腐蚀质量损失量逐渐降低,并在腐蚀72 h后趋于平缓,在整个试验周期内,Q345B钢的腐蚀质量损失量始终大于Q345qDNH钢;在腐蚀后期(120 h),Q345B钢发生了严重的点蚀,而Q345qDNH钢表面锈层较完整,膜层致密性较高,对金属基体的保护作用较好,耐蚀性较好;Q345B钢和Q345qDNH钢表面腐蚀产物的主要成分均为α-FeOOH、γ-FeOOH和Fe_(3)O_(4),但各组分含量及膜层厚度存在差异;随着试验时间的延长,Q345qDNH钢表面腐蚀产物内膜层厚度明显增大,Ni、Cr和Cu氧化产物富集于内膜层,这增强了氧化膜层的致密性和稳定性,从而提高了材料的耐蚀性。

The corrosion behavior and evolution of corrosion product film of Q345qDNH bridge weathering steel in simulated industrial atmospheric corrosion environment wered studied by wetting-drying cycle immersion corrosion test,and compared with Q345B steel.The results show that in the simulated process atmospheric environment,the corrosion mass loss of Q345qDNH steel decreased gradually with the extension of the wetting period,and tended to be gentle after 72 hours of corrosion.During the whole test period,the corrosion mass loss of Q345B steel was always greater than that of Q345qDNH steel.In the later stage of corrosion(120 h),serious pitting corrosion occurred on Q345B steel,while the rust layer on the surface of Q345qDNH steel was relatively complete,the film was dense,the protection effect on the metal matrix was more obvious,and the corrosion resistance was higher.The main components of corrosion products on the surface of Q345B steel and Q345qDNH steel wereα-FeOOH,γ-FeOOH and Fe_(3)O_(4),but the content of each component and the thickness of the film were different.With the increase of test time,the thickness of the inner layer of corrosion products on the surface of Q345qDNH steel increased significantly,and the oxidation products of Ni,Cr and Cu were enriched in the inner layer,which enhanced the compactness and stability of the oxidation film layer,thereby improving the corrosion resistance of the material.