Abstract:Ni-S(La) coatings were obtained by electrodeposition in a typical Watt bath by adding CS(NH₂)₂ and LaCl₃. The minimum HER overpotential is 75mV. The corresponding electrochemical parameters (Tafelslope b,exchanging current density J₀) were obtained by measuring the steady-state polarization curves. The content of S, La in the coating and its structure were measured by EPMA and XRD. The results show that there is no lanthanum in such coating and its structureis amorphous. From the anodic polarization curves, it is shown that the corrosion resistance of coating is very good. Based on the cathodic polarizatio n curves during electrodeposition, it is found that LaCl₃ is benefit for amorphous coating structure to form.

Key words: rare earth; electrodeposition; Ni-S alloy; HER