钕铁硼在CuCl-EMIC离子液体中电沉积铜层的研究

Electrodeposition of Copper on NdFeB in CuCl-EMIC Ionic Liquid

目的开发一种新型的环保型钕铁硼表面镀铜技术。方法采用CuCl-EMIC离子液体,对钕铁硼基体进行阳极活化前处理,在其表面电沉积铜。通过电化学工作站测试CuCl-EMIC离子液体的循环伏安曲线和镀铜样品的动电位极化曲线,运用扫描电子显微镜、能谱分析仪和X射线粉末衍射仪,考察钕铁硼基体和铜镀层的微观形貌、成分组成和相结构,利用粗糙度仪和拉拔试验仪检测钕铁硼表面的粗糙度和其上铜镀层的结合力。结果物质的量之比为2∶3~3∶2的CuCl-EMIC离子液体在室温下熔融,可在其中电沉积得到晶态铜。物质的量之比为1的CuCl-EMIC离子液体有更大的还原峰值电流密度。钕铁硼基体经过20~30mA/cm^2的电流密度阳极活化后,表面变得平整,孔洞减少,活化后钕铁硼表面的铜镀层均匀致密,结合力达9.2MPa以上。钕铁硼表面铜镀层的孔隙率随着镀层厚度的增加而减小,当厚度为6μm时,镀铜试样的腐蚀电位与纯铜相近,孔隙率为0.00523%。结论采用物质的量之比为1的CuCl-EMIC离子液体,可以通过阳极活化得到平整、孔洞少和无氧化膜的钕铁硼基体表面,在其上电沉积可得到致密均匀且结合力好的薄铜层。

The work aims to develop a new environment-friendly copper plating technology on the surface of NdFeB.The CuCl-EMIC ionic liquid was used to pretreat the NdFeB matrix by anodic activation,and the copper layer was prepared on NdFeB surface by electrodeposition.Cyclic voltammetry curves of the CuCl-EMIC ionic liquid and potentiodynamic polarization curves of copper coating samples were measured by electrochemical workstation.The morphology,composition and phase structure of the NdFeB matrix and copper coatings were investigated by scanning electron microscopy,energy dispersive spectrometry and X-ray powder diffraction.The surface roughness of the NdFeB matrix and the bonding force of copper coatings were detected by the roughness meter and the drawing tester.CuCl-EMIC could be melted at room temperature when the molar ratio was 2:3~3:2,and crystalline copper layers could be obtained by electrodeposition from the CuCl-EMIC ionic liquid.The CuCl-EMIC ionic liquid with molar ratio of 1 had larger reduction peak current density.The NdFeB matrix was activated by the anodic current density of 20~30 mA/cm^2,the surface became smoother and the voids were less.Copper coatings on NdFeB surface were more uniform and denser after activation,and the bonding force was more than 9.2 MPa.The porosity of copper coatings on NdFeB surface decreased with the increase of the coating thickness.When the thickness was 6 μm,the corrosion potential of the samples was similar to that of pure copper,and the porosity was 0.005 23%.By CuCl-EMIC ionic liquid with molar ratio of 1,the NdFeB matrix with smoother surface,fewer holes and no oxide film can be obtained by anodic activation,and the thin compact and uniform copper layer with good bonding can be electrodeposited on the surface of NdFeB.