铅铋共晶合金的流动速度对CLAM钢腐蚀行为的影响

Corrosion Behavior of CLAM Steel in Various Flow Velocities of Pb-Bi Eutectic Alloy

为了研究中国低活化马氏体(CLAM)钢在不同相对流速铅铋共晶合金(LBE)中的腐蚀行为,本研究对CLAM钢在550℃不同流动速度(0 m/s、1.70 m/s、2.98 m/s、3.69 m/s、4.77 m/s)的液态LBE中进行了500 h的腐蚀试验。试验后分别对腐蚀试样表面进行SEM、XRD检测以及对试样截面进行SEM-EDS和面扫描检测。结果表明,经过500 h腐蚀试验后的试样表面均形成双层结构的氧化层,外氧化层由Fe 3O 4组成,内氧化层由(Fe,Cr)3O 4组成。在LBE相对流速从0 m/s增大到2.98 m/s的过程中,试样表面氧化层的厚度逐渐增大,这是由于相对流速的增大提高了Fe元素的溶解速率和O元素的扩散迁移速率,进而导致试样表面发生严重的氧化腐蚀。而当LBE相对流速从2.98 m/s继续增大到4.77 m/s时,CLAM钢表面的氧化层厚度逐渐减小,这是由于随着LBE相对流速的进一步增大,试样表面冲蚀腐蚀程度逐渐加重,外氧化层厚度因遭受一定程度的剥落而急剧减小,进而使得试样表面总氧化层的厚度逐渐减小。本研究结果为未来ADS嬗变系统的实际应用提供了数据支持和参考。

A iming at exploring the corrosion behavior of CLAM steel in lead bismuth eutectic alloy (LBE) with diverse relative flow velocities, the corrosion tests of CLAM steel in liquid LBE with diverse flow velocities (0 m/s, 1.70 m/s, 2.98 m/s, 3.69 m/s, 4.77 m/s) at 550 ℃ for 500 h were carried out. The SEM, XRD were employed to characterize the the surface of CLAM steel samples after corrosion, and the SEM-EDS analysis and mapping scanning were conducted on the cross section of the corrosion samples of CLAM steel, respectively. After the corrosion test for 500 h, a bilayer oxide structure could be found on the surface of the CLAM steel samples. The outer oxide layer was composed of Fe 3O 4, and the inner oxide layer was composed of (Fe,Cr) 3O 4. When the relative flow velocity of LBE increased from 0 m/s to 2.98 m/s, the thickness of the oxide layer on the samples grew gradually, which could be attributed to the acceleration of the dissolution of Fe and diffusion migration of O by the increasing LBE relative flow rate, leading to critical oxidation corrosion. However, when the relative flow velocity of LBE rose from 2.98 m/s to 4.77 m/s, the thickness of the oxide layer on the samples decreased gradually, which because the degree of erosion-corrosion aggravated with the increase of the LBE flow velocity, and the oxide layer suffered a certain degree of spalling. Therefore, the thickness of the oxide layer gradually decreased with the increase of the LBE flow velocity.The results of the study on the corrosion behavior of CLAM steel in liquid LBE with various flow velocities are expected to provide data support and reference for the practical application of ADS system in the future.