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通过高压釜腐蚀实验研究了Zr-XSn-1Nb-0.3Fe合金(X=0~1.5,质量分数,%)在360℃/18.6 MPa纯水、360℃/18.6 MPa/0.01 mol·L-1 LiOH水溶液以及400℃/10.3 MPa过热蒸汽中的耐腐蚀性能。结果表明,随着Sn含量从1.5%降低至0.6%,合金试样腐蚀增重降低;进一步降低Sn含量时,合金在纯水和蒸汽中的腐蚀增重没有明显变化,但在LiOH水溶液中的腐蚀增重反而增加。采用透射电镜表征腐蚀前的显微组织发现,随着Sn含量的变化,合金中第二相的大小及类型相接近,但面密度随着Sn含量的增加而减少。采用激光拉曼光谱分析腐蚀过程中氧化膜晶体结构表明,腐蚀初期氧化膜的结构以m-ZrO2和t-ZrO2为主,随着腐蚀时间的增加,t-ZrO2转变为m-ZrO2;t-ZrO2转变越快,t-ZrO2含量越低,腐蚀速率越高。
The effects of Zr-XSn-1Nb-0.3Fe alloy (X = 0-1.5, mass fraction,%) at 360 ℃ / 18.6 MPa pure water, 360 ℃ / 18.6 MPa / 0.01 mol·L-1 LiOH Aqueous solution and 400 ℃ / 10.3 MPa superheated steam corrosion resistance. The results show that with the Sn content reduced from 1.5% to 0.6%, the corrosion resistance of the alloy sample decreases. When the Sn content is further reduced, the corrosion weight gain of the alloy in pure water and steam does not change significantly. However, in the LiOH aqueous solution Corrosion weight gain but increased. Transmission electron microscope was used to characterize the microstructure before corrosion. It was found that with the change of Sn content, the size and type of the second phase in the alloy are close, but the areal density decreases with the increase of Sn content. The laser Raman spectroscopy analysis of the crystal structure of the oxide film during the etching shows that the structure of the oxide film is mainly m-ZrO2 and t-ZrO2 at the initial stage of the etching, and the t-ZrO2 is changed to m-ZrO2 as the etching time increases; ZrO2 transition faster, t-ZrO2 content is lower, the higher the corrosion rate.