甲酸盐型三价铬电镀液电化学研究

Electrochemical Study of Trivalent Chromium Plating Solutin Containing Formate

研究了甲酸盐型三价铬镀液的电化学特性,通过循环伏安、动电位扫描、恒电位电镀、恒电流电镀证实了Cr^(3+)在电位负于—1.3V后开始还原为Cr,在-0.9V～-1.3V之间还原为Cr^(2+),Cr^(2+)是暂时的,在溶液中极不稳定.但能加速配体交换反应。讨论了Cr^(3+)电沉积的电极过程和镀层不能加厚的原因。

Electrochemical characteristics of trivalent chromium plating solution from formate was studied. By means of cyclic voltammogram,potentiodynamic polarization,potentiostatic electroplating and galvanostatic electroplating,it has testified that Cr3+reduce Cr after potential is more negative than-1. 3V;C3+reduce Cr2+when potential is be tween-0. 9^-1. 3V. Although Cr2+ is highly unsteady.it can accelerate ligand exchang processes. It has also been discussed for electrode processes of trivalent chromium electroplating and the reason for the plated film cannot be thickened.