Corrosion behavior of 9Cr-ODS steel in stagnant liquid lithium and lead–lithium at 873 K
Corrosion behavior of 9Cr-ODS steel in stagnant liquid lithium and lead–lithium at 873 K
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DOI：
10.1016/j.jnucmat.2013.07.026
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发表时间：
2013-11
影响因子：
3.1
通讯作者：
Yanfen Li;H. Abe;T. Nagasaka;T. Muroga;M. Kondo
中科院分区：
文献类型：
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作者：
Yanfen Li;H. Abe;T. Nagasaka;T. Muroga;M. Kondo
对9Cr-ODS钢进行了873 K静态Li环境下250 h的腐蚀实验，并与9Cr-ODS钢在相同暴露条件下的Pb-Li环境下的腐蚀实验进行了比较。暴露于液态锂后，9Cr-ODS表现出轻微的失重和近表面硬度下降。拉伸性能在973 K时变化不大，而蠕变性能在973 K时下降。金相分析表明，9Cr-ODS表现出不均匀的晶界腐蚀行为和明显的球状形貌。通过化学成分分析，在深度约15 μm处检测到Cr的轻微损耗。根据生成自由能的计算，9Cr-ODS中tio2纳米级氧化物颗粒的热力学稳定性较差，而y2o3在Li环境下比Li2O更稳定。然而，y2o3可以与Li反应生成YLiO2。腐蚀机理为基体中的Cr和Fe在液态Li中轻微溶解，纳米级氧化物颗粒与Li发生化学相互作用，Li优先向晶界攻击和渗透，最终在Li清洗过程中形成极端结核状结构。相反，9Cr-ODS在Pb-Li中表现出更大的失重和近表面Cr损耗，而在Li中表现出更不明显的腐蚀形态，这可能是由于Cr和Fe在Pb-Li中的溶解度高于Li，而Li在Pb-Li中的活性低于Li。
Corrosion experiments of 9Cr-ODS steel were carried out in static Li at 873 K for 250 h and compared with those of 9Cr-ODS in Pb–Li at the same exposure conditions. After exposure to liquid Li, 9Cr-ODS showed slight weight loss and decrease in hardness near surface. The tensile property exhibited a negligible change at 973 K and the creep property degraded at 973 K. By metallurgical analyses, 9Cr-ODS demonstrated a non-uniform corrosion behavior by preferential grain boundary attack and pronounced nodule-like morphology. The slight depletion of Cr was detected to about 15 μm in depth by chemical composition analyses. According to the calculation of free energy of formation, the nano-scale oxide particles of TiO2in 9Cr-ODS were thermodynamically less stable while Y2O3were more stable compared with those of Li2O in Li environment. However, Y2O3may be reacted with Li to form YLiO2. The mechanism of corrosion was proposed as the slight dissolution of Cr and Fe in matrix into liquid Li, chemical interaction of nano-scale oxide particles with Li, preferential grain boundary attack and penetration of Li, and finally development of extreme nodule-like structure during cleaning of Li. On the contrary, 9Cr-ODS showed much larger weight loss and depletion of Cr near surface but less marked corroded morphology in Pb–Li than in Li, which may be derived from higher solubility of Cr and Fe and lower activity of Li in Pb–Li than in Li.