溶胶-硬脂酸封闭法对锌与铝阴极间结合力的影响

Effects of Sol-Stearic Acid Sealing on Adhesion of Electrodeposited Zinc to Aluminium Cathodes

目的降低电锌与铝阴极间的结合力,提高剥锌效率,研究锌电积过程中锌成核以及结合力的变化情况。方法采用溶胶-硬脂酸封闭法对铝阴极表面进行处理,通过电子扫描显微镜观查铝阴极表面形貌及锌电积初期成核情况,采用万能试验机测试锌铝间结合力,同时结合电沉积实验考察封闭铝板对电流效率的影响。结果封闭铝板表面微孔被封闭,整体光滑平整。与普通铝板相比,其成核率较低,以晶核的长大为主。结合强度呈现出"中心高、四周低"的规律,且结合力随着电积次数的增加而增大。封闭铝板局部结合强度峰值自5.64 kg/cm^2增加到6.34 kg/cm^2,相较普通板结合强度降低了30%左右,在很大程度上降低了剥锌难度。封闭铝板电流效率的平稳性也优于普通铝板。结论采用溶胶-硬脂酸封闭法来降低铝阴极与锌间结合力,降低剥锌难度和提高脱锌效率,切实可行。

The work aims to variation of zinc nucleation and adhesion during zinc electrodeposition by reducing adhesion of electrodeposited zinc to aluminum cathodes, which results in improvement of zinc stripping efficiency. Sol-stearic acid sealing was applied to aluminum cathodes, surface morphology of cathode surfaces and nucleation during initial zinc electrodeposition were observed with scanning electron microscope, adhesion between zinc and aluminum was tested with universal testing machine, and effects of sealed sheet on current efficiency were investigated by performing electrodeposition experiment. Micropores on the surface of sealed sheet were sealed, and the plate was smooth and flat as a whole. Nucleation rate of the sealed sheet was lower than that of common aluminum sheet. The former mainly featured in development of crystal nucleus. In addition, its bonding strength was ＂high in the center, and low all around＂, and the adhesion increased as electrodeposition times increased. Local maximum bonding strength of the sealed sheet increased from 5.64 kg/cm2 to 6.34 kg/cm2, about 30% lower than that of common sheet, which significantly reduced difficulty of zinc stripping. Moreover, the current efficiency of sealed sheet was more stable than that of the aluminium sheets. It is practical to reduce adhesion of zinc to aluminium cathodes, reduce difficulty of zinc stripping and improve zinc stripping efficiency.