Effect of gelatin additive on microstructure and composition of electrodeposited rhenium-nickel alloys in aqueous solutions

摘要

Re-Ni alloys with high Re content were electrodeposited galvanostatically from aqueous solutions with addition of gelatin. The influence of gelatin on the Faradaic efficiency (FE), chemical composition, morphology and crystallographic structure of the alloys was investigated. Morphology, surface roughness, chemical composition and phase identification of the alloys were characterized by an environmental scanning electron microscopy, atomic force microscopy, energy-dispersive spectroscopy and X-ray diffraction, respectively. The addition of gelatin in the plating led to the increase in Re content, and the decrease in the FE and deposition rate. In the absence and presence of gelatin, the alloys with high Re content consisted of an amorphous phase. The addition of gelatin resulted in small amount of carbon in the alloys due to the adsorption of gelatin in the alloy. The gelatin had a great influence on the morphology of the alloys, resulting in significant grain coarsening, the increase in surface roughness and the decrease in crack size. The optimum concentration of gelatin was found to be about 0.9-2.7 g L~(-1).