铜、锌离子浓度比对羟基乙叉二膦酸体系电镀黄铜的影响

Effect of Cu^(2+)/Zn^(2+)concentration ratio on brass electroplating from 1-hydroxyethylidene-1,1-diphosphonic acid-based bath

以羟基乙叉二膦酸(HEDP)为配位剂进行电镀黄铜(Cu–Zn合金),通过阴极极化测试、循环伏安分析、扫描电镜(SEM)观察、X射线衍射(XRD)等手段研究了Cu^(2+)/Zn^(2+)浓度比对电沉积过程及镀层微观结构的影响。结果表明,HEDP体系中Cu–Zn合金电沉积的电位介于Cu和Zn之间。随Cu^(2+)/Zn^(2+)浓度比减小,Cu–Zn合金的初始沉积电位正移,共沉积得到促进,镀层的Zn质量分数增大。Cu^(2+)/Zn^(2+)浓度比为1:4时所得Cu–Zn合金镀层为金黄色,微观上呈均匀分布的胞状结构,镀层中Cu的质量分数在65%~70%之间,与氰化物电镀黄铜的组成最接近。

Brass(Cu–Zn alloy)electroplating was carried out with 1-hydroxyethylidene-1,1-diphosphonic acid(HEDP)as complexing agent.The effect of Cu^(2+)/Zn^(2+)concentration ratio on the electrodeposition process and microstructure of deposit was studied by cathodic polarization measurement,cyclic voltammetry,scanning electron microscopy(SEM),and X-ray diffraction(XRD).The results showed that the electrodeposition potential of Cu–Zn alloy was between the deposition potentials of Cu and Zn.With the decreasing of the concentration ratio of Cu^(2+)to Zn^(2+),the initial deposition potential of Cu–Zn alloy shifted toward a positive direction,which indicated that the codeposition of Cu–Zn alloy was promoted,resulting in an increase of zinc content in the deposit.The Cu–Zn alloy coating electrodeposited at a Cu^(2+)/Zn^(2+)concentration ratio of 1:4 was golden yellow,exhibited a uniformly distributed cellular structure microscopically,and contained 65%to 70%by mass of Cu,which was close to the composition of Cu–Zn alloy coating electrodeposited from a cyanide-containing bath.