关键词: 镍电沉积, NH₃-NH₄Cl-H₂O体系, 丙烯基硫脲, 添加剂

Abstract: The effects of allylthiourea (ATU) concentration on the cathodic polarization behaviour, nucleation and surface morphology of nickel electrodeposited on the glassy carbon electrode from ammonia-ammonium chloride-water (NH₃-NH₄Cl-H₂O) solutions were investigated by cyclic voltammogry, cathodic polarization and current transient methods. The results revealed that the addition of ATU inhibited nickel deposition, which was enhanced with an increase in ATU concentration from 5 to 50 mg•L^-1. The initial deposition kinetics corresponded to a model including instantaneous nucleation and diffusion controlled growth. In the presence of ATU, the initial nucleation of nickel electrocrystallisation remained unchanged. However, the number density of nuclei increased and the crystal growth rate decreased. Furthermore, the addition of ATU apparently made the grains finer, leading to the formation of a more compact and uniform nickel deposit as compared with that without ATU.

Key words: nickel electrodeposition, NH3-NH4Cl-H2O solution, allyl thiourea, additive