【摘要】 采用干湿循环加速腐蚀实验,研究了Q345qNH耐候钢和Q345q桥梁钢在模拟西北地区工业大气环境的腐蚀介质（除冰盐+0.01 mol/L NaHSO₃）中的腐蚀行为。用失重法研究了两种钢的腐蚀动力学曲线,并使用XRD、SEM和电化学工作站等手段分析了两种钢腐蚀不同时间后锈层的物相、形貌结构及其电化学特性。结果表明:在除冰盐+NaHSO₃的混合介质中,Q345qNH钢腐蚀100 h前的失重稍大于Q345q钢,腐蚀100 h后桥梁钢的失重量明显大于耐候钢;两种钢的腐蚀产物均由α-FeOOH,β-FeOOH,γ-FeOOH,Fe₂O₃,Fe₃O₄和FeOCl构成,但是Q345q钢中生成的不稳定β-FeOOH和FeOCl的含量明显高于Q345qNH钢,锈层的稳定性降低;随着腐蚀时间的延长两种钢锈层的自腐蚀电位均增大,自腐蚀电流密度均波动性减小,Q345qNH耐候钢的自腐蚀电位增大的速度高于Q345q钢,腐蚀后期其锈层的保护性优于普通桥梁钢。两种钢在混合介质中的腐蚀行为受多离子的耦合效应影响,锈层的致密性因β-FeOOH和FeOCl等不稳定腐蚀产物的生成而降低,但是仍有一定的保护性。Q345qNH耐候钢在除冰盐+0.01 mol/L NaHSO3混合介质中的耐蚀性优于Q345q普通桥梁钢。更多还原

【Abstract】 Corrosion behavior of Q345 qNH weathering steel and Q345 q ordinary bridge steel in a mixed medium of simulated industrial environment solution and deicing salt was investigated by means of wet/dry cyclic accelerated corrosion test, The corrosion kinetics curves of the two steels were studied by weight loss method, and the phase, morphological structure and electrochemical characteristics of the rust layer after corrosion of the two steels for different times were analyzed using XRD, SEM and electrochemical workstation. The results show that the corrosion weight loss of Q345 qNH weathering steel is slightly higher than that of Q345 q bridge steel before 100 h. However, after 100 h the corrosion mass loss of bridge steel is obviously larger than that of weathering steel. The corrosion products were composed of α-FeOOH, β-FeOOH, γ-FeOOH, Fe₂O₃, Fe₃O₄ and FeOCl, but the content of unstable β-FeOOH and FeOCl on Q345 q bridge steel was significantly higher than that on Q345 qNH weathering steel, thereby, the rust scale on Q345 q bridge steel presented lower stability; the free-corrosion potential of the rust layer on the two steels increased with the increasing time, and the free-corrosion potential of Q345 qNH weathering steel increased faster than that of Q345 q bridge steel, while, their free-corrosion current density showed undulatory attenuation. The protectiveness of the rust layer of weathering steel was better than that of ordinary bridge steel in the later stage of corrosion; the corrosion behavior of the two steels in the mixed medium was affected by the coupling effect of various ions. Due to the existence of unstable corrosion products such as β-FeOOH and FeOCl, the compactness of the rust layer reduced, even so, which still maintained protectiveness to certain extent. In general, the corrosion resistance of Q345 qNH weathering bridge steel in the mixed media was better than that of Q345 q ordinary bridge steel.更多还原