Cu在Zr-2.5Nb-0.5Cu合金及其腐蚀生成氧化膜中的存在形式

Existing Form of Cu in Zr-2.5Nb-0.5Cu Alloys and the Oxide Films during Corrosion Testing in SCW at 550℃/25 MPa

用电子显微镜研究了合金元素Cu在Zr-2.5Nb-0.5Cu合金及其腐蚀生成氧化膜中的存在形式。合金基体中的元素Cu主要以四方结构的CuZr2第二相形式存在,CuZr2相中会富集杂质元素Fe。合金经过550℃,25MPa超临界水条件深度腐蚀后,伴随着合金基体发生的H致β相变,CuZr2第二相也发生了相消溶、扩散及凝聚长大过程。在腐蚀生成的氧化膜中,合金元素Cu以非晶氧化物的形式存在于氧化锆的晶界。

Scanning electron microscopy（SEM） and high resolution transmission electron microscopy（HRTEM）,equipped with an energy dispersive X-ray spectroscopy（EDS） were employed for examining the existing form of Cu in Zr-2.5Nb-0.5Cu alloys and the oxide films during corrosion testing in SCW（supercritical water） at 550 oC/25 MPa.In Zr-2.5Nb-0.5Cu alloy,Cu exists mainly in the form of tetragonal second phase CuZr2,rich in impurity element Fe.The CuZr2 are transferred and agglomerated with the β phase transformation of the alloy induced by hydrogen during the corrosion testing.In the form of amorphous cuprous oxide,Cu segregates on the grain boundaries of zirconia in the oxide films during corrosion testing.