Zr－4合金氧化膜（＜100nm）的电镜研究

Electron Microscopy Investigation of Oxide Films (<100 nm) Formed on Zircaloy-4

应用透射电子显微镜（ＴＥＭ），分析了Ｚｒ－４合金在３５０℃空气中生成的氧化膜（＜１００ｎｍ）。氧化膜中ＺｒＯ２的晶体结构为非晶、立方（四方）和单斜，它们所占份额与基体晶粒的取向有关。第二相粒子与周围基体构成电偶腐蚀，加速基体氧化，因而第二相粒子周围的氧化膜较厚，第二相粒子自身氧化变慢，将残留在氧化膜中。第二相粒子的氧化产物为六方（Ｆｅ、Ｃｒ）２Ｏ３、立方（四方）ＺｒＯ２和单斜ＺｒＯ２。

The oxide film (<100 nm) formed on Zircaloy-4 in air at 350℃ has been investigated bymeans of Transmission Electron Microscopy, the crystal structure of the oxide films mainlyconsists of armorphpous, cubic (tetragonal) and monoclinic Zr-O2, and their content is relatedto the crystal orentation of the substrate. The galvanic corrosion, induced by the second phaseparticles coupled to the matrix, exists and accelerates the oxidation of the matrix adjioning thesecond phase particles to form thicker oxide film and delays the oxidation of the second phaseparticles to be embeded in the oxide film. The oxide of the second phase are hexagonal (Fe.Cr)2O3. cubic (tetragonal) ZrO2and monoclinic ZrO2.