电流密度对纳米锌镍合金镀层显微组织的影响

采用适当的添加剂在碱性体系中获得了晶粒度为14—33 nm的纳米锌镍合金电镀层。并应用赫尔槽试验、透射电镜(TEM)、扫描电镜(SEM)和X射线衍射(XRD)等技术研究了电流密度对镀层晶体结构的影响。结果表明,在该体系中,在电流密度为0.5—50 A/dm2得到的纳米锌镍合金镀层均为单一的γ-相(N i5Zn21)结构。随电流密度的增加,在低电流密度区镀层的晶粒度由33 nm迅速降至17 nm,在中高电流密度区晶粒度保持在14—17 nm。另外,镀层中还存在亚微米级晶粒团簇,其尺寸随电流密度的增加呈线性增大。

Influence of current density on microstructure of nanocrystalline Zinc Nickel alloy deposition

The zinc nickel alloy depositions with grain size of 14-33 nm were electroplated by using adequate additives in an alkaline bath.The microstructures and phase compositions of the depositions were analyzed by TEM,SEM and XRD technologies.It was demonstrated that the depositions obtained from the bath with current density range of 0.5-50 A/dm~2 are all single γ-phase(Ni_5Zn_(21)).Crystal size decreases from 33 nm to 17 nm with the increase of current density in low current density range,and tend to stable in the range of 14-17 nm in medium and high current density range.There are many clusters of grains,whose sizes increase linearly with the increase of current density.