This study investigated the characteristics of corrosion products formed on the contact and exposed regions of C1045 steel bolt and nut fasteners used in structures exposed to aqueous chloride environments. The corroded surface morphology, rust compositions, and corrosion kinetics of the bolt specimen were studied by visual observation, optical microscopy (OM), scanning electron microscopy (SEM), X-Ray diffractometry (XRD), micro-Raman, electron probe micro-analyzer (EPMA), and potentiodynamic polarization techniques. Results obtained showed a variation in corrosion kinetics, morphology, and composition of the rust layer which were driven by differential aeration and concentration effects. Due to the availability of sufficient dissolved oxygen, the oxyhydroxide compound, lepidocrocite (γ-FeOOH) was detected in the outer rust layer in the exposed region, whereas the inner rust layer was composed of magnetite (Fe₃O₄). However, the oxygen-deficient contact surface revealed the presence of akaganeite (β-FeOOH) and magnetite (Fe₃O₄) as dominant oxide phases. The most stable phase, goethite (α-FeOOH) was also detected in the rust formed in both regions, though in significantly low amounts. Furthermore, owing to variation in environmental conditions, the amount and density of the rust layer varied in the different regions. The estimated corrosion stability values for the different regions revealed that the corrosion products formed on the steel surfaces were non-protective, suggesting the need for specific surface treatment as a protective measure.

本研究调查了在暴露于氯化物水溶液环境的结构中使用的 C1045 钢螺栓和螺母紧固件的接触和暴露区域形成的腐蚀产物的特征。采用目视观察、光学显微镜（OM）、扫描电子显微镜（SEM）、X射线衍射仪（XRD）、显微拉曼光谱、电子探针显微仪对螺栓试样的腐蚀表面形貌、锈成分和腐蚀动力学进行了研究。分析仪（EPMA）和动电位极化技术。获得的结果表明腐蚀动力学、形态和锈层组成的变化是由不同的曝气和浓度效应驱动的。由于有足够的溶解氧，羟基氧化物化合物，₃ O ₄ )。然而，缺氧的接触表面揭示了作为主要氧化物相的 akaganeite (β-FeOOH) 和磁铁矿 (Fe ₃ O _{4 ) 的存在。}在这两个区域形成的铁锈中也检测到最稳定的相针铁矿（α-FeO​​OH），尽管含量非常低。此外，由于环境条件的变化，锈层的数量和密度在不同地区也有所不同。不同区域的估计腐蚀稳定性值表明，在钢表面上形成的腐蚀产物是非保护性的，表明需要进行特定的表面处理作为保护措施。