利用XPS及电化学方法研究电镀Cr添加剂的作用机理

STUDY ON MECHANISM OF ADDITIVES FOR CHROMIUM ELECTRODEPOSITION BY XPS AND ELECTROCHEMICAL METHODS

利用阴极极化曲线、电化学交流阻抗图谱、微分电容曲线对含有机物的镀 Ｃｒ添加剂进行了研究提出了添加剂在阴极 表面形成一种（Ｒ（ＯＨ）_ｎ·ＣｒＯＨ·ＣｒＯ_４＋ Ｃｒ（ＯＨ）_３·ＣｒＯＨ·ＣｒＯ_４）（Ｒ代表有机物）荷正电的混合阴极胶体膜，较好地解释了 添加剂对阴极析 Ｃｒ的去极化作用，以及溶液反应电阻增高、微分电容下降、析氢电流降低等现象．通过对镀层进行表层及深层的 ＸＰＳ分析。

The mechanism of organic additives for chromium electrodeposition was studied by using the cathode polarization curves, differential capacitance curves. A suggestion of the formation of a kind of new cathode film, (R(OH)_n.CrOH.CrO_4+ Cr(OH)_3.CrOH.CrO_4), was put forward and used successfully to explain some phenomena such as the depolarization effect of additives, the increase of reaction resistance, the decrease of differential capacitance and so on. This hypothesis has been confirmed by the XPS analysis of chromium depositions.