Zr-Nb系合金在360℃/20MPa溶氧水中的腐蚀行为

Corrosion Behavior of Zr-Nb Alloys in 360℃/20MPa Water with Dissolved Oxygen

通过高温高压(360℃/20MPa)动态循环水回路系统,研究了在含1.5mg/L溶解氧的水中,Zr-Nb系合金(M5和E110)的早期腐蚀行为。利用透射电子显微镜(TEM)分析了两种锆合金氧化膜的显微特性,以及氧化膜/基体(O/M)界面特性和靠近界面处β-Nb相的腐蚀行为。结果表明:腐蚀60d后M5与E110合金表面的氧化膜厚度分别为3.2μm与2.1μm。M5合金的腐蚀已经发生转折,而E110合金的未发生转折。两种合金O/M界面处的结构有很大差异,在E110合金的O/M界面处存在ZrO过渡层,这与其氧化膜较慢的生长速率相关。两种合金中靠近O/M界面处的β-Nb相均被部分氧化,溶解氧(DO)可以加速β-Nb相的氧化。

Early corrosion behavior of Zr-Nb alloys(M5 and E110)in 1.5 mg/L dissolved oxygen water was studied through a high temperature and high pressure(360℃/20 MPa)dynamic circulating water loop system.The microscopic characteristics of oxide films of two zirconium alloys,oxide film/matrix(O/M)interface characteristics and corrosion behavior ofβ-Nb phase near interface were analyzed by transmission electron microscopy(TEM).The results show that the thicknesses of the oxide films on the surface of M5 and E110 alloys reached 3.2μm and 2.1μm respectivly,after corrosion of 60 days.The corrosion of M5 alloy had already turned,while that of E110 alloy had not.The structures of O/M interface of the two alloys were very different.There was a ZrO transition layer at the O/M interface of E110,which was related to the slower growth rate of the oxide film.Theβ-Nb phases near the O/M interface in oxide films of the two alloys were partially oxidized,and dissolved oxygen(DO)could accelerate the oxidation ofβ-Nb phase.