Abstract: The Ni-Mo-Co alloy coating was prepared by pulse plating process. The effects of different electrodeposition conditions on the composition， apparent morphology and hydrogen evolution reaction (HER) activity of the Ni-Mo-Co coating were investigated. The results showed that with the increasing addition of cobalt salt， the cobalt content in the coating increased and the molybdenum content decreased. When the concentration of cobalt salt was up to 81 g/L， the content of elements became less changeable. Moreover， the Ni-Mo-Co coating appeared to be a uniform and dense layer and the corresponding HER overpotential decreased to the minimum value. With the Mo content of 40 wt%， the degree of amorphous structure and the catalytic activity (80℃，η₂₀₀=56mV) of the Ni-Mo-Co coating increased with increasing of the Co content. After galvanostatic electrolysis， the bubble phenomenon happened， which indicated a poor stability.

Key words: pulse plating, Ni-Mo-Co alloy, hydrogen evolution activity, amorphous state, surface structure