稀土对电沉积Zn-Fe-La三元合金性能影响的研究

Investigation of the Effects of Rare-earth on Electrodeposite Zn-Fe-La Ternary Alloy

为了获得更加光亮、致密的Zn-Fe-La三元合金镀层,针对电沉积Zn-Fe-La三元合金镀液组成及工艺条件,系统地研究了稀土对镀层成分含量、镀液稳定性、镀液分散能力以及pH值的影响,测定了镀层的极化曲线、稳定电位和极化电阻,比较了不同稀土含量对镀层耐蚀性的影响。结果表明:稀土的加入可提高镀液稳定性、分散能力,增加电沉积过程阴极极化,使阳极钝化前的活性区腐蚀电位正移,自溶解速度下降,有利于提高镀层耐蚀性,其耐蚀性比Zn-Fe合金镀层及纯Zn镀层有很大提高。

In order to obtain more bright and compact Zn-Fe-La ternary alloy, in accordance with the composition and process conditions of electrodeposition Zn-Fe-La ternary alloy electrolyte, （i） the effects of the rare earth on the content of coat, electrolyte stability, dispersancy and pH were investigated systematically ; （ ii ） polarization curve, stationary potential and polarization resistance were determined ; （iii） the effects of different rare＇earth contents on the corrosion resistivity were compared in the study. It was shown that the addition of rare earth could enhance electrolyte stability, dispersancy, increase cathodic polarization of electrodeposition, make active zone corrosion potential of anode passivation move positively, and reduce self dissolving rate, which were favorable to the enhancement of coat corrosion resistivity. The corrosion resistivity of coat of electrodeposition Zn-Fe-La ternary alloy was increased greatly compared to those of Zn-Fe alloy coat and pure Zn coat.