不同成分Ni-Al合金去合金化过程中的结构演化与机理

摘要

A method of vacuum melting combined with rapid solidification was used to prepare the thin tape of Ni-Al precursive alloy with Ni atomic fractions from 15% to 40%, different techniques of dealloying was employed to prepare the nanoporous SEM nickel, X-ray diffractometer (XRD) and scanning electronmicroscope (SEM) were utilized to analyse its phase composition and microstructure, and the influence of the composition of Ni-Al precursive alloy and its dealloying techniques on microstructure of nano-porous nickel and its forming mechanism were investigated.The result showed that the nanoporous Ni could be formed with chemical dealloying of the alloy with atomic fraction of nickel from 15% to 30%,and it could be formed with electrochemical dealloying of the alloy with atom fraction of nickel from 25% to 40%.The porous structure formed with electrochemical dealloying would be more uniform and the skeletal size ligament smaller than the one formed with chemical dealloying.The synergetic corrosive function of the two phases would have a promoting effect on dealloying and would have an important influence on the morphology of nanoporous nickel and the forming of the structure of multilayer nanoporous nickel.%采用真空熔炼与快速凝固相结合的方法制备Ni(原子分数)为15%~40%的Ni-Al前驱体合金薄带,通过不同去合金化工艺制备纳米多孔镍,用X射线衍射仪(XRD)、扫描电镜(SEM)分析多孔镍的相组成和微观形貌,研究前驱体Ni-Al合金成分与去合金化工艺对纳米多孔镍微观结构的影响及其形成机理.结果表明:镍原子分数为15%~30%时,可通过化学去合金化形成纳米多孔Ni,镍原子分数为25%~40%时,可通过电化学去合金化形成纳米多孔结构.相同成分的Ni-Al合金,电化学去合金化较化学去合金化获得的多孔结构更为均匀,骨架尺寸相对较小.2相的协同腐蚀作用对去合金化具有促进作用,且对纳米多孔镍的形貌及多层次纳米多孔结构的形成有重要影响.