Liu Chao, Cheng Xuequn, Dai Zeyu, Liu Ryan, Li Ziyu, Cui Liying, Chen Mindong, Ke Le
Institute of Advanced Materials & Technology, University of Science and Technology Beijing, Beijing 100083, China.
The Calverton School, Huntingtown, MD 20639, USA.
Materials (Basel). 2018 Nov 14;11(11):2277. doi: 10.3390/ma11112277.
The initiation and evolution of the localized corrosion in carbon steel were investigated in a simulated marine environment of Xisha Island in the South China Sea. In the initial stage, localized corrosion occurred in the form of corrosion spot. The localized corrosion morphology and electrochemical information during corrosion process were tracked by field emission scanning electron microscopy energy dispersive spectrometry (FE-SEM-EDS), scanning vibrating electrode technique (SVET) and scanning Kelvin probe force microscopy (SKPFM). Localized corrosion was induced by the microcrevices around Al₂O₃ inclusions. The occluded cells and oxygen concentration cell formed in the pits could accelerate the localized corrosion. Pearlite accelerated the dissolution of the inside and surrounding ferrite via the galvanic effect between Fe₃C and ferrite. Overall, the localized corrosion was initiated and evaluated under a synergistic effect of crevice corrosion, occluded cells, oxygen concentration cell and the galvanic couple between FeC₃ and ferrite.
在南海西沙群岛的模拟海洋环境中，对碳钢局部腐蚀的萌生与演变进行了研究。在初始阶段，局部腐蚀以腐蚀点的形式出现。通过场发射扫描电子显微镜能谱仪（FE-SEM-EDS）、扫描振动电极技术（SVET）和扫描开尔文探针力显微镜（SKPFM）跟踪腐蚀过程中的局部腐蚀形态和电化学信息。Al₂O₃夹杂物周围的微缝隙引发了局部腐蚀。蚀坑中形成的闭塞电池和氧浓差电池会加速局部腐蚀。珠光体通过Fe₃C与铁素体之间的电偶效应加速了内部及周围铁素体的溶解。总体而言，局部腐蚀是在缝隙腐蚀、闭塞电池、氧浓差电池以及FeC₃与铁素体之间的电偶对的协同作用下萌生和发展的。
