Electrochemically-Grown Oxides on U-NB Alloy.

[摘要] Electrochemically-grown oxides on U-Nb alloys (2 - 8 wt. %o) were mixed oxides consisting of varying amounts of Nb205, U03(2HZO), and UOZ. Nb enhanced the passivity of U in acidic and neutral solutions through the formation of Nb205 and enrichment of Nb in the oxide. In highly acidic solutions, where U did not form a solid oxide, Nb additions greater than 8% would be required to achieve passivity. In alkaline solutions Nb did not significantly increase the passivity of the mixed oxide and there was no enrichment of Nb. U-8Nb, which had a lower I(Pass) than Nb or U in pH 10.7 solution, was the exception; the behavior is thought to be due to the unique U-8Nb phase structure. In highly alkaline solutions, Nb was shown to be an ineffective alloy element for promoting passivity because, although it formed Nb205, the oxide was non-protective.

[发布机构] Technical Information Center Oak Ridge Tennessee

[学科分类] 工程和技术（综合）

[关键词] Electrochemical corrosion;Protective coatings;Uranium alloys;Niobium alloys;Oxidation