Real-Time Microelectrochemical Observations of Very Early Stage Pitting on Ferrite-Pearlite Steel in Chloride Solutions
Real-Time Microelectrochemical Observations of Very Early Stage Pitting on Ferrite-Pearlite Steel in Chloride Solutions
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DOI：
10.1149/2.0801706jes
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发表时间：
2017-01-01
影响因子：
3.9
通讯作者：
Hara, Nobuyoshi
中科院分区：
文献类型：
--
作者：
Kadowaki, Mariko;Muto, Izumi;Hara, Nobuyoshi
研究了具有初生铁素体和珠光体组织的AISI 1045碳钢在pH 8.0的含NaCl和不含NaCl的硼-硼酸盐缓冲溶液中的点蚀早期萌生位置和形貌。微尺度极化引起的点蚀只发生在珠光体中，而不发生在初生铁素体中。在原位实时观察过程中的微尺度极化珠光体在硼硼酸盐缓冲溶液与100 mM NaCl表明，坑是多边形或棒状的形状。此外，还发现点蚀的生长方向与由铁素体和铁素体组成的珠光体片层的生长方向相同。场发射电子探针显微分析检测到铁素体片层中硫的偏聚点。根据它们在3%Nital中的腐蚀行为，估算了铁素体片层组织的耐腐蚀性高于铁素体片层组织。因此，凹坑容易在铁氧体薄片中开始并沿着铁氧体薄片进行。(C)作者（S）2017由ECS发布。
The initiation site and morphology during the early stage of pitting on AISI 1045 carbon steel that has a microstructure of primary ferrite and pearlite were investigated in boric-borate buffer solutions with andwithout NaCl at pH 8.0. The pits initiated by micro-scale polarization were in the pearlite only and not in primary ferrite. In situ real-time observations during the micro-scale polarization of pearlite in a boric-borate buffer solution with 100 mM NaCl indicated that the pits were polygonal or rod-like in shape. In addition, it was found that the pit growth direction was the same as that of the pearlite lamellae that consisted of ferrite and cementite. Field-emission electron probe micro analysis detected segregated points of sulfur in the ferrite lamellae. On the basis of their etching behavior in 3% nital, the corrosion resistance of the cementite was estimated to be higher than that of the ferrite lamellar structure. Thus, pits readily initiated in the ferrite lamellae and proceeded along the ferrite lamellae. (C) The Author(s) 2017. Published by ECS.