Microstructuring of carbon nanotubes-nickel nanocomposite

In this paper, we develop a novel electroplating method for the synthesis of carbon nanotubes (CNTs)-nickel (Ni) nanocomposite, and present the fabrication of a silicon micromirror with the CNTs-Ni nanocomposite beams to evaluate the mechanical stability of the micromirror in terms of resonant frequency. CNTs are pretreated to have positive charges on their surface and added into a Ni electroplating solution to form a CNTs-Ni nanocomposite electroplating suspension. The weight fraction of the CNTs in the electroplated nanocomposite is 2.4 wt%, and the ultramicroindentation hardness is 18.6 GPa. The mechanical strengthening phenomenon is found in the nanocomposite in comparison with a Ni film. Moreover, the addition of CNTs in the nanocomposite beams effectively increases the shear modulus compared with the pure Ni. The maximum variation of the resonant frequency of the micromirror during a long-term stability test is approximately 0.25%, and its scanning angle is approximately 20°. It shows the potential suitability of the CNTs-Ni nanocomposite with proper design for micromechanical element applications. (paper)