机械研磨辅助电镀制备Ni镀层的耐腐蚀性能

Corrosion resistance of Ni coating prepared by mechanical attrition(MA)-assisted electroplating

采用机械研磨辅助直流电镀法,在碳钢表面制备出了连续致密的镍镀层。利用场发射扫描电镜、透射电镜、能谱仪、X射线衍射仪、原子力显微镜等研究了镀层的形貌、微观结构和粗糙度;利用维氏硬度计和摩擦磨损仪测试镀层的硬度和摩擦系数;采用Tafel动态极化曲线和电化学阻抗测试比较机械研磨辅助镀层和未施加机械研磨镀层的耐蚀性。结果表明:与传统电镀镀层相比,机械研磨辅助制备的Ni镀层为纳米级的细晶结构,表面更光滑,且具有更高的硬度和更低的摩擦系数,较传统镀层分别提高了1倍和降低了11.8%;极化曲线和电化学阻抗谱图表明,纳米晶态Ni镀层具有较低的腐蚀电流密度,较大的容抗弧和较高的阻抗模量,表明MA辅助电镀镍镀层具有较高的耐腐蚀性能。

A continuous and dense nickel coating was prepared on the surface of carbon steel using mechanical attrition(MA)-assisted direct current electroplating method.Morphology,microstructure and roughness of the coating were studied by means of field emission scanning electron microscopy,transmission electron microscopy,energy dispersive spectrometer,X-ray diffraction and atomic force microscopy.Hardness and friction coefficient of the coating were tested by Vickers hardness tester and friction and wear tester.The Tafel dynamic polarization curve and electrochemical impedance test were used to compare the corrosion resistance of MA-assisted electroplating coating and the coating without mechanical attrition.The results show that compared with traditional electroplating coating,the Ni coating prepared by MA-assisted electroplating has a nanoscale fine crystal structure,smoother surface,higher hardness,and lower friction coefficient,which increases by 1 times and decreases by 11.8%respectively compared to the traditional coating.The polarization curves and electrochemical impedance spectra show that the nanocrystalline Ni coating has a lower corrosion current density,a larger capacitance arc,and a higher impedance modulus,indicating that MA-assisted electroplated Ni coating has higher corrosion resistance.