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不同Si元素含量9Cr耐热钢熔敷金属铅铋腐蚀行为

Corrosion behavior of 9Cr heat-resistant steel deposited metal with different Si contents in lead-bismuth

  • 摘要: 为研究Si元素含量对9Cr铁素体-马氏体耐热钢熔敷金属在液态铅铋中腐蚀行为的影响,将不同Si元素含量9Cr铁素体-马氏体钢熔敷金属分别在550 ℃饱和氧及控氧(氧浓度:1 × 10−6% ~ 5 × 10−6%,质量分数)静态铅铋中进行腐蚀试验. 结果表明,熔敷金属在550 ℃饱和氧铅铋中形成双层结构氧化层,在550 ℃控氧铅铋中形成不连续钝化层和厚度不均匀的双层结构氧化层,钝化层在腐蚀过程中会通过渗透机制和断裂机制在部分区域发生失效,失效区域氧化加剧形成双层结构氧化层. 随着熔敷金属中Si元素含量的增加,饱和氧铅铋中的氧化层厚度降低,控氧铅铋中的钝化层连续性提高,熔敷金属在铅铋中的耐蚀性提高.

     

    Abstract: In order to investigate the effect of Si content on the corrosion behavior of 9Cr ferritic-martensitic heat-resistant steel deposited metal in liquid lead-bismuth alloy, corrosion experiments were performed on 9Cr ferritic-martensitic steel deposited metal with different Si contents in saturated oxygen and controlled oxygen (oxygen concentration: 1 ×10−6 ~ 5 × 10−6 wt.%) static lead-bismuth at 550 ℃, respectively. The results show that the double-layered oxide scale forms on the surface of deposited metal in saturated oxygen lead-bismuth at 550 ℃, and the discontinuous passivation layer and the double-layered oxide scale with uneven thickness form on deposited metal in oxygen-controlled lead-bismuth at 550 ℃. The passivation layer will fail in some areas during the corrosion process through penetration mechanism and film breakdown mechanism, where oxidation aggravates to form the double-layered oxide scale. With the increase of Si content in the deposited metal, the thickness of the oxide layer in the saturated oxygen lead-bismuth decreases, the continuity of the passivation layer in the controlled oxygen lead-bismuth increases, and the corrosion resistance of the deposited metal in the lead-bismuth increases.

     

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