地质处置低氧过渡期X65低碳钢腐蚀行为研究  

Corrosion Behaivour of X65 Low Carbon Steel During Redox State Transition Process of High Level Nuclear Waste Disposal

作　　者：刘灿帅 田朝晖 张志明[1] 王俭秋[1] 韩恩厚[1] LIU Canshuai;TIAN Zhaohui;ZHANG Zhiming;WANG Jianqiu;HAN En-Hou(Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Suzhou Nuclear Power Research Institute Co.,Ltd.,Suzhou 215008,China)

机构地区：[1]中国科学院金属研究所中国科学院核用材料与安全评价重点实验室,沈阳110016 [2]苏州热工研究院有限公司,苏州215008

出　　处：《金属学报》2019年第7期849-858,共10页Acta Metallurgica Sinica

基　　金：中国科学院前沿科学重点研究计划项目No.QYZDY-SSWJSC012及中国科学院重点资助项目No.ZDRW-CN-2017-1~~

摘　　要：利用实验室自行搭建的低氧手套箱电化学测试体系系统,长期监测X65低碳钢在模拟地质处置过渡期80℃低氧饱和膨润土中的电化学腐蚀行为,发现X65低碳钢的开路电位在150 d内逐渐降低,阻抗模逐渐增加,腐蚀类型从初期的点蚀转变为均匀腐蚀;利用SEM、EDS和μ-XRD表征了X65低碳钢腐蚀产物的形貌、元素组成和物相组成,发现腐蚀产物有颗粒状、片状、杆状和胞状4种类型,腐蚀产物中的元素均匀分布,产物物相由Fe3O4和α-Fe2O3组成;使用失重法测量X65低碳钢平均腐蚀速率,发现腐蚀速率(V)在150 d内逐渐从195.88μm/a降低到20.58μm/a,V随时间(t)的变化规律符合降幂函数关系式V=8.34t-0.88,腐蚀过程受扩散控制。Domestic and foreign researches on the corrosion behavior of low carbon steel canister in high level nuclear waste geological repositories focus on the initial aerobic stage and the later anaerobic stage, while few researches have been reported on the corrosion behavior during the disposal transition period. The long term electrochemical corrosion behavior of X65 low carbon steel in 80 ℃ Gaomiaozi bentonite saturated with anaerobic Beishan groundwater has been studied by electrochemical measurement system in anaerobic glovebox constructed independently. The results indicated that the open circuit potential of X65 low carbon steel decreased gradually during 150 d, while the electrochemical impedance of the corrosion film increased with immersion time. Pitting corrosion occurred at the beginning of immersion tests, and finally transformed into general corrosion. Morphologies, compositions, and phases of the corrosion film formed on the carbon steel surface were examined by SEM, EDS and μ-XRD. The results showed that the corrosion film was mainly composed of blocks, slices, rods and swellings. The elemental distribution in the corrosion film was uniform, and the phases were composed of magnetite and hematite.The average corrosion rates were detected by weight loss measurement, which decreased from 195.88μm/a to 20.58 μm/a. The corrosion rates(V) followed a power function pattern V=8.34 t-0.88, indicating that the film growth process was controlled by oxygen diffusion.

关 键 词：地质处置 低碳钢 腐蚀 电化学 扩散 

分 类 号：TF777.1[冶金工程—钢铁冶金]