铅锌合金电沉积层的组成结构和形态

Composition, Structure and Morphology of Ph-Zn Alloy Electrodeposit

采用X-射线衍射（XRD）、金相显微镜技术及电化学方法研究了铅锌合金电沉积层和Zn经阳极溶出后的镀层结构、组成和表面形态。结果表明，Pb-Zn合金电沉积层不能形成固溶体。XRD图仅出现与铅面心立方结构以及与锌密集六方结构相对应的各品面衍射线，其中较低Pb含量的Pb－Zn合金中Pb基本上为无序取向的晶体，而Zn则为（002）晶面择优，但择优度不高。沉积层经控电位阳极溶出后，其XRD图仍存在铅晶体的各晶面衍射线，而锌晶休各晶面衍射线消失；同时也出现表征正棱形PbSO4晶体的各晶面衍射线。金相实验结果表明：铅锌电沉积层表面由排列整齐的棱锥状晶粒构成；随镀层中Zn含量的增大，沉积层表面逐渐平整，棱锥状晶粒变小，最终形成团粒状态。锌溶出后的铅晶电极表面由原来的凹凸不平变成平整，且晶粒显著细小。

The Composition, structure and morphology of Pb-Zn alloy electrodeposit and the one in which zinc was anodically dissolved were investigated by XRD and OM.The experimental results showed that the Pb-Zn alloy deposit could not be formed in solid solution. There were only diffraction peaks of different crystal planes corresponding to lead FCC and zinc HCP structures.Lead crystals in Pb-Zn alloy with lower Pb content were mainly with random orientation, whereas zinc crystals were with (002) plane preferred orientation.After the deposits were anodically dissolved, the diffraction peaks of lead crystals still existed but that of zinc crystals disappeared, and the diffraction peaks of orthorhombic PbSO. crystals emerged instead. PbZn alloy deposits consisted of taper grains in a regular but tough arrangement. As the zinc content increased the surfaces of deposits gradually become smooth, the taper grains smaller and in granular groups.