【摘要】 利用SEM和EDXA对Zr-Sn-Nb合金碘致应力腐蚀断口上的腐蚀产物进行了观察分析。结果表明:腐蚀产物的成分主要是氧和锆,只有局部准解理断裂区域可检测到碘,碘与氧在锆基体上竞争吸附,形成不具保护作用的膜,促进局部严重氧化;应力、碘分压、合金成分及热处理状态等因素会影响腐蚀产物的特征,这些影响作用与碘的扩散、合金中第二相的数量以及Zr-I-O体系的化学平衡有关。更多还原

【Abstract】 The corrosion products on the I-SCC fracture of Zr-Sn-Nb alloys have been investigated by SEM and EDXA. The result shows that, the products are mainly composed of Zr and O; and I can only be detected on the local pseud-cleavage zone. The adsorption of iodine at bare metal surface would be competing with that of oxygen. This could lead to the formation of a non-protective film and thus promote locally serious oxidation in test atmosphere. The stress, iodine partial pressure, composition of alloys and heat-treatment state would influence the morphology and thickness of the corrosion products, which can be explained by the diffusion of iodine, the quantities of precipitation particles or the reaction balance of Zr-I-O system.更多还原