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研究第二相大小和种类对Zr-2和Zr-4合金在400℃,10.3MPa过热蒸气中腐蚀吸氢行为的影响。结果表明:吸氢量的多少和耐腐蚀性能的好坏之间并不一定存在严格的对应关系,而是与第二相大小和种类密切相关。在相同腐蚀增重下,含粗大第二相样品的吸氢量均大于含细小第二相样品;第二相比较粗大的Zr-2样品的吸氢量比Zr-4样品大得多;而第二相比较细小的Zr-2和Zr-4样品的吸氢量差别却很小。对Zr(Fe,Cr)2和Zr2(Fe,Ni)金属间化合物及纯锆进行的PCT和吸放氢动力学测试表明,前两者可自由吸放氢,且吸放氢速度快,而纯锆只能吸氢难以放氢。据此,Zr-Sn系合金在400℃,10.3MPa过热蒸气中腐蚀吸氢行为可以用提出的“在金属/氧化膜界面处Zr和OH-反应生成的氢可以优先被镶嵌在金属/氧化膜界面处的可逆吸放氢能力强于Zr的Zr(Fe,Cr)2和Zr2(Fe,Ni)第二相捕获,它们可作为吸氢的优先通道”的吸氢模型得到合理解释。
The influence of the size and type of the second phase on the hydrogen evolution behavior of Zr-2 and Zr-4 alloys in superheated steam at 400 ℃ and 10.3 MPa was investigated. The results show that there is not necessarily a strict correspondence between the amount of hydrogen absorption and the corrosion resistance, but closely related to the size and type of the second phase. Under the same corrosion weight gain, the amount of hydrogen absorbed by the coarse second-phase sample is greater than that of the second small-phase sample; the second-phase coarse Zr-2 sample has a much greater hydrogen uptake than the Zr-4 sample; The second is slightly smaller Zr-2 and Zr-4 samples of hydrogen absorption difference is small. The tests of PCT and hydrogen absorption and desorption kinetics on Zr (Fe, Cr) 2 and Zr2 (Fe, Ni) intermetallics and pure zirconium show that the first two are free to absorb and release hydrogen, Pure zirconium can only absorb hydrogen difficult to discharge hydrogen. Accordingly, the corrosion hydrogen absorption behavior of Zr-Sn-based alloys in superheated steam at 400 ° C and 10.3 MPa can be demonstrated by the proposed "hydrogen generated by the reaction of Zr and OH- at the metal / oxide interface preferentially inlaid in the metal / oxide The reversible hydrogen absorption and desorption capacity at the membrane interface is stronger than that of the Zr (Fe, Cr) 2 and Zr2 (Fe, Ni) second phases, which can be reasonably explained as the hydrogen absorption model for hydrogen absorption.