Zhao Zhong, Huo Guanying, Li Huifang
College of Computer and Information, Hohai University, Changzhou 213022, China.
School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212000, China.
Micromachines (Basel). 2022 Dec 23;14(1):34. doi: 10.3390/mi14010034.
Electroplating nanocrystallite Ni coating can improve the mechanical properties of the metal structure surface, which is widely used in fabricating metal MEMS devices. Because of the large internal compressive stress caused by the oxidation layer of the substrate surface, the Ni coating easily falls off from the substrate surface. To solve this bonding problem, the ultrasonic assisted electrochemical potential activation method was applied. The ultrasonic experiments have been carried out. The bonding strength was measured by the indentation method. The substrate surface oxygen element was tested by the X-ray photoelectron spectroscopy (XPS) method. The dislocation was observed by the TEM method. The compressive stress was tested by the XRD method. The coating surface roughness was investigated by the contact profilometer method. The results indicated that the ultrasonic activation method can remove the oxygen content of the substrate surface and reduce the dislocation density of the electroplating Ni coating. Then, the compressive stress of the electroplated Ni coating has been reduced and the bonding strength has been improved. From the viewpoint of the compressive stress caused by the oxygen element of the substrate surface, mechanisms of the ultrasonic activation method to improve the bonding strength were researched originally. This work may contribute to enhancing the interfacial bonding strength of metal MEMS devices.
电镀纳米晶镍涂层可以改善金属结构表面的机械性能，广泛应用于金属微机电系统（MEMS）器件的制造。由于基体表面氧化层产生的较大内压应力，镍涂层容易从基体表面脱落。为了解决这种结合问题，采用了超声辅助电化学电位活化方法。进行了超声实验。通过压痕法测量结合强度。用X射线光电子能谱（XPS）法测试基体表面氧元素。用透射电子显微镜（TEM）法观察位错。用X射线衍射（XRD）法测试压应力。用接触轮廓仪法研究涂层表面粗糙度。结果表明，超声活化方法可以去除基体表面的氧含量，降低电镀镍涂层的位错密度。然后，降低了电镀镍涂层的压应力，提高了结合强度。从基体表面氧元素引起的压应力角度出发，首次研究了超声活化方法提高结合强度的机理。这项工作可能有助于提高金属MEMS器件的界面结合强度。
