Influence of bath composition on the electrodeposition of amorphous Ni‐Mo alloys using potassium‐sodium tartrate as complexing agent

Abstract

Currently, sodium citrate is the most used complexing agent for electrodeposition of Ni-Mo coatings, especially for studying the effect of bath temperature and current density on the proprieties of Ni-Mo coatings. This study evaluates the influence of the concentrations of nickel sulphate and sodium molybdate on the electrodeposition of Ni-Mo alloys in baths using tartrate as a complexing agent. Electrodepositions were carried out in a two-electrode cell. A 3 2 complete factorial design of experiments along with response surface methodology (RSM) was used for the optimization of bath variables for electrodeposition of Ni-Mo alloys. The coatings obtained were characterized in terms of chemical composition and surface morphology. The chemical composition of the coatings was most influenced by the sodium molybdate concentration. Ni-Mo coatings of good quality were obtained in potassium-sodium tartrate baths with Mo content in the range 18-44 wt%; some results present even higher Mo content than coatings obtained from citrate baths. The coating with the highest Mo content was deposited from the bath with a concentration ratio of nickel sulphate to sodium molybdate of 1:1. Surface morphology varied according to chemical composition, and microcracks were observed for the coating with 41 wt% Mo, for which scanning electron microscopy (SEM) images also show the presence of nodules. The most homogeneous coating surface was obtained at a concentration ratio of nickel sulphate to sodium molybdate of 10:3. X-ray diffraction analyses have shown that all coatings obtained in this work are amorphous.

Stable zinc anode by regulating the solvated shell and electrode–electrolyte interface with a sodium tartrate additive

“…It has an excellent ability to chelate most divalent and trivalent metal ions. 49 Herein, sodium tartrate is proposed as a novel organic electrolyte additive for ZIBs to suppress the formation of dendrites and reduce side reactions (mainly suppression of hydrogen evolution), constructing a stable electrode-electrolyte interface. Combining the experimental results and theoretical calculation, it is found that a stronger adsorption energy between STA and the Zn metal surface induces preferential adsorption of STA on Zn foil, inhibiting the growth of dendrites.…”

Electrodeposition of crack-free and amorphous Ni-Mo alloys with high Mo content from gluconate baths

“…Even though citrate baths tend to be reasonably stable for Ni-Mo electrodeposition and using less stable complexing agents might not be recommended, there are examples where such complexing agents have been used. In a previous study, we investigated the influence of bath chemistry on the electrodeposition of Ni-Mo alloys from tartrate baths in acidic media [13]. Other films can also be obtained using mono-or bi-valent ligands.…”