关键词: Ni-W-B合金, 电沉积, 成核机理, 晶粒尺寸

Abstract: The electrodeposition characteristics and grain sizes of Ni_W_B alloy have been studied by cyclic voltammetry, potentiostatic step and X_ray diffraction (XRD). The results showed that Ni_W_B alloy electrodeposit obtained from the solution containing ammonium citrate as a complexing agent was presented in the lower electrochemical activity compared with Ni_W alloy. Based upon the i～t curves of potentiostatic step, it was revealed that electrocrystallization of Ni_W_B alloy on glassy carbon followed the mechanism of instantaneous nucleation and three dimensional growth with diffusion controlled. The crystal nucleus number on the surface of electrode was raised by the increase of overpotential. According to XRD experimental results, the grain sizes of the alloy deposits were gradually increased by the rising of deposition current densities, which elucidates that the increase of current density was more benefit to nucleus growing during the electrocrystallization of Ni_W_B alloy.

Key words: Ni_W_B alloy, Electrodeposition, Nucleation, Grain size