重水堆用Zr-2.5Nb合金高压釜预生膜的制备及性能

Preparation and Characteristic of Autoclaved Oxide Film on Zr-2.5Nb Alloy for Heavy Water Reactor

采用静态高压釜在400℃过热蒸汽中对国产冷加工压力管用Zr-2.5Nb合金进行预膜处理,研究了蒸汽压力(1、5、10 MPa)和晶体结构各向异性对Zr-2.5Nb合金预生膜生长速率的影响;对预生膜试样进行高温水环境下的微动磨损试验,并利用二次离子质谱仪对腐蚀后的预生膜进行了氢分布表征。结果表明:冷加工Zr-2.5Nb合金为双相组织,基体为薄片状α-Zr晶粒,晶界分布着连续的薄膜状β-Zr相;蒸汽压力对预生膜生长速率有一定影响,而合金基体晶体结构的各向异性对预生膜生长速率及形貌均有显著影响;预生膜可在一定程度上改善Zr-2.5Nb合金压力管的耐磨性能、耐蚀性能和抗吸氢性能。

Zr-2.5Nb alloy used for the domestic cold-worked pressure tube was pre-filmed in super-heated steam at 400 ℃ by a static autoclave,the effect of steam pressure(1,5,10 MPa) and anisotropy of crystal structure on the growth rate of oxide film on Zr-2.5Nb alloy was investigated.The fretting wear test in aqueous environment at elevated temperature was carried out upon the prefilmed sample,and the hydrogen distribution along the depth of corroded oxide film was characterized by the secondary ion mass spectroscopy.The results showed that the cold-worked Zr-2.5Nb alloy exhibited a duplex structure,the matrix consisted of flake α-Zr grains surrounded by continuous β-Zr thin film at the grain boundary.The steam pressure had a certain effect on the growth rate of the oxide film,while the structure anisotropy of the alloy matrix had a significant effect on the growth rate and morphology of the oxide film.The oxide film could improve the wear resistance,corrosion resistance and hydrogen absorption resistance of Zr-2.5Nb alloy pressure tube to a certain extent.