摘要
采用静态高压釜腐蚀试验研究了Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr-xBi(x=0.1,0.3和0.5,质量分数,%)合金在400℃/10.3 MPa过热蒸汽中的腐蚀行为;并用TEM、EDS和SEM观察分析了合金和腐蚀后氧化膜的显微组织。结果表明,在Zr-0.8Sin0.35Nb-0.4Fe0.1Cr合金中添加0.1%,0.3%和0.5%的铋对其在400℃过热蒸汽中的耐腐蚀性能都有较大改善作用,但随着铋含量的增加,其改善作用减弱;在Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr合金中添加0.1%铋后,合金中只有Zr(Fe,Cr,Nb)_2一种第二相;添加0.3%铋后,有Zr(Fe,Cr,Nb)_2和Zr-Fe-Sn-Bi两种第二相析出;添加0.5%铋后,有Zr(Fe,Cr,Nb)_2,Zr-Fe-Sn-Bi和Zr-Fe-Cr-Nb-Sn-Bi三种第二相析出;Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr合金中添加适量铋会促进原来固溶的锡以第二相析出。以上结果说明Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr-xBi合金在580℃时α-Zr基体中可固溶不少于0.1%的铋,这对改善合金的耐腐蚀性能是有利的,但含铋和锡第二相的析出则使合金的耐腐蚀性能下降。
An autoclave was employed to investigate the effect of Bi contents on the corrosion resistance of Zr-0. 8Sn- 0. 35Nb-0. 4Fe-0. 1Cr-ccBi （x=0. 1%--0. 5%, mass fraction） alloys in superheated steam at 400 ℃ and 10. 3 MPa. The microstructures of the alloys and oxide films on the corroded specimens were observed by TEM and SEM, respectively. The results show that （0. 1%--0. 5 ~） Bi addition can improve the corrosion resistance of the Zr-0. 8Sn- 0. 35Nb-0. 4Fe-0. 1Cr alloy, but the degree of the improvement effect decreases with the increase of Bi contents. Only Zr（Fe,Cr,Nb）2 second phase particles （SPPs） were detected in the alloy with 0.1% Bi; Zr（Fe,Cr,Nb）2 and Zr-Fe- Sn-Bi SPPs were detected in the alloy with 0. 3 % Bi. Zr（Fe, Cr, Nb）2, Zr-Fe-Sn-Bi and Zr-Fe-Cr-Nb-Sn-Bi SPPs were detected in the alloy with 0.5 % Bi. This implies that the Bi addition promotes the precipitation of Sn as the SPPs and the solid solubility of Bi in a-Zr matrix of Zr-0. 8Sn-0. 35Nb-0. 4Fe-0. 1Cr-xBi alloys is not less than 0. 1% at 580 ℃. From the above results, it can be concluded that the Bi as solid solution in a-Zr matrix can improve the corrosion resistance, however, the precipitation of SPPs containing Bi and Sn is deleterious to the corrosion resistance.
出处
《腐蚀与防护》
CAS
北大核心
2013年第6期463-467,481,共6页
Corrosion & Protection
基金
国家自然科学基金(50971084)
国家先进压水堆重大专项(2011ZX06004-023)
北京科技大学新金属材料国家重点实验室(2009Z-10)
关键词
锆合金
铋
耐腐蚀性能
显微组织
zirconium alloy
Bi
corrosion resistance
microstructure
