镀液成分对低碳钢板镀铬层的形成及其耐蚀性能的影响

Effect of Bath Composition on Formation and Corrosion Resistance of Chromium-deposited Coating on Low-carbon Sheet

镀铬的实质是钢板在含铬酸盐的镀液中通过电解沉积形成镀层。不同成分的镀液具有不同的特性,对镀铬层的性能有重要影响。采用循环伏安法(CV)、计时安培法以及交流阻抗法(EIS)研究了镀液成分对冷轧低碳钢板镀铬层的形成机制的影响,以及镀铬层孔隙率与其电化学性质之间的关系。结果表明:随着镀液中CrO_(3)含量的减少,基板镀铬层的形成机制由三维沉积转变为二维沉积;在CrO_(3)的质量浓度为150 g/L的镀液中形成的镀铬层孔隙率为1.05 mg/dm^(2),镀层钝化膜电阻为259.2Ω。此外,三维沉积的镀铬层致密度好,耐蚀性优异。

Chromium plating is substantially formation of coating on steel sheet in a bath having chromate with the aid of electrolytic deposition.The bath with different compositions has varied characteristics,and will exert an important influence on performance of the chromium plate.The effect of bath composition on the formation mechanism of chromium plate on a cold-rolled low-carbon sheet,as well as the relationship between porosity of the chromium plate and its electrochemical property,was investigated by cyclic voltammetry,chronoamperometry and AC impedance.It was found that with the decrease of CrO_(3) content in the bath,the formation mechanism of chromium plate on the basis sheet changed from three-dimensional deposition to two-dimensional deposition,and the chromium plate formed in the bath with of 150 g of CrO_(3) per litre of bath offered porosity of 1.05 mg per dm^(2) and passive film resistance of 259.2Ω.Also,the chromium plate formed by three-dimensional deposition had good compactness thereby excellent corrosion resistance.