镧系元素对铬酸镀铬电解液性能的影响

报导了在镀铬电解液中添加镧系元素（镧和铽）后，使该电解液电沉积金属铬的覆盖能力及阴极电流效率显著提高。研究中采用微分电容，交流阻抗测试技术以及Ｘ光电子能谱测定，探明了镧和铽是以特性吸附的方式参与了阴极膜的形成，使阴极膜电阻增大，表征电极表面状态变化的极化曲线的电流峰值下降，析出金属铬的电位正移，使铬能在较低的阴极电流密度下沉积，因而显著地改善了覆盖能力。添加镧和铽后使阴极电流效率提高，这可能是因为

The Effect of Lanthanoids on the Performances of Chromic Acid Chromium Plating Electrolyte

That addition of lanthanoids(espeicailly La and Tb)in the chromium acid chromium electroplating electrolyte improves significantly the performances of the electrolyte, eg. , marked increasing in covering power and cathodic current efficiency of the electrolyte ,is reported in this paper.In experiments techniques such as differential capacitance curve,AC impedance and XPS are employed to study the effect of lanthanum and terbium respectively in chromium electroplating process.The experimental results indicate that lanthanum and terbium has participated in the formation of cathode surface film with manner of specific adsorption,leading to the increase in resistance of cathode surface film,to the decrease in current of peak characterizing surface state change of the cathode on the polarization curve, and to the shift of deposition potential of metallic chromium in the positive direction.These make metallic chromium deposition occurs at lower cathodic current densities.Thus covering power of the electrolyte is improved. Increase in cathodic current efficiency after the addition of lanthanum or terbium in the chromium plating electrolyte is probably due to the cathode surface film containing lanthanum or terbium having positive effect on the cathode major reaction and having negative effect on side reactions.