Zr-Nb-Fe合金在LiOH溶液中的腐蚀行为

摘要

The corrosion behavior of Zr-Nb-Fe in lithiated solution(360 ℃, 18.6 MPa, 0.01 mol/L) was investigated by autoclave tests. The microstructure of Zr-Nb-Fe alloy and the morphology of oxide film were observed by OM, SEM and TEM. The results show that the second phase particles(SPPs) including β-Nb with a body-center cubic(BCC) and Zr(Nb, Fe)2with a hexagonal close packed(HCP) structure and face-center cubic(FCC) structure are observed in Zr-Nb-Fe alloy. The corrosion mass curve breaks away when the Zr-Nb-Fe alloy is corroded for 150 d, then the corrosion rate increases rapidly. Cellular bulge morphology is forms on the external surface of oxide film and the surrounding oxide film is thick and loose. Cellular bulge morphology formed on the tube specimen is roundish compare with that formed on the plate specimen. The hydrogen uptake of specimen after breaking away increases but hydrogen uptake fraction decreases. So the formation of cellular bulge morphology is related to the unabsorbed hydrogen diffusing out through oxide film.%利用静态高压釜腐蚀试验研究了Zr-Nb-Fe管状样品在LiOH溶液(360 ℃, 18.6 MPa, 0.01 mol/L)中的腐蚀行为;利用OM、SEM和TEM观察了合金和氧化膜的显微组织和氧化膜的形貌.结果表明:Zr-Nb-Fe合金中的第二相为体心立方的β-Nb、面心立方和密排六方的Zr(Nb,Fe)2.Zr-Nb-Fe管状样品腐蚀150 d时腐蚀增质曲线发生转折,转折后的腐蚀速率显著加快,氧化膜表面出现包状凸起,该包状凸起比片状样品的凸起形貌较圆些,其周围氧化膜明显变厚且较为疏松.转折后样品的吸氢量虽有增加,吸氢分数却明显降低,因而氧化膜中包状凸起的形成与未被锆合金吸收的氢需要通过氧化膜向外逸出有关.