Electrochemical Synthesis of Nickel-Rhenium Alloys
The rhenium alloys with nickel are promising materials with numerous useful properties: high mechanical and magnetic characteristics, microhardness, wear and corrosion resistances, and improved electrocatalytic properties. The development of new methods for the synthesis of Ni-Re alloys is of particular interest. Electrodeposition produces nanocrystalline materials when electrocrystallization results in massive nucleation and reduced grain growth. Electrodeposition is one of the most promising techniques for producing nanostructure materials owing to its low cost. However, problems related with intensification of electrodeposition and convenient control of Ni-Re alloys still limit the larger application.
It is important to establish the relationships between the kinetics of codeposition of the metals (Re and Ni) in the alloy and its composition, structure, and corrosion properties. In order to produce Ni-Re alloys, we can use stable nontoxic electrolytes. We have proposed sulfamate and citrate bath of Re-Ni electrodeposition [1,2]. The mechanism (induced and classic) of electrochemical synthesis of nickel-rhenium alloys in this electrolytes was studied [2]. The composition, structure and morphology of the Ni-Re deposits obtained depend on the composition of the electrolyte and the modes of electrolysis. Ni-Re containing over 90 at.% of Re are deposited from citrate electrolytes; the use of sulfamate electrolyte allows to increase the current efficiency (from 20 to 90%), but simultaneously the Re content is reduced (60 at.%). The effect of complexation on the efficiency of precipitation is considered. Changing the complex composition of the electrolyte and hydrodynamic conditions allows to vary the chemical composition and size of Ni-Re crystallites. As the fraction of rhenium in the deposit increases, the grain size decreases and the corrosion resistance becomes lower. As temperature increases, the Re content of the alloy from a sulfamate electrolyte decreases. It is shown that the structure of the alloys is nanocrystalline.
Analysis of the electronic configuration of metals shows that the highest catalytic effect on the hydrogen evolution reaction (HER) should be observed when one metal has d4-d5-, and another d6-d8-electron configuration [3,4]. Therefore, rhenium alloys exhibit electrocatalytic properties in the reaction of hydrogen evolution [5].
As corrosive, electrocatalytic and mechanic properties of coatings depend not only on chemical, but also on phase composition, these characteristics in this study were analyzed as a function of composition and structure of obtained Re-alloys.
electrodeposition, rhenium alloy, nanocrystalline structure, electrocatalytic properties
This research has received funding through the MSCA4Ukraine project, which is funded by the European Union (Project No. 1233494).
[1] Bersirova, O., Kublanovsky, V., “Nickel-Rhenium Electrolytic Alloys: Synthesis, Structure, and Corrosion Properties”, Materials Science, 2019, 54(4), pp. 506–511.
[2] Bersirova, O; Bilyk, S. and Kublanovsky, V, “Electrodeposition of Ni-Re alloys from sulfamate and citrate electrolytes”, Ukr. Khim. Zh. – 2017- 83 (6), pp.110-116.
[3] Kuznetsov, V.V., Gamburg, Yu.D., Zhulikov, V.V., Krutskikh, V.M., Filatova, E.A., Trigub, A.L., Belyakova, O.A., Electrodeposited NiMo, CoMo, ReNi, and electroless NiReP alloys as cathode materials for hydrogen evolution reaction / Electrochimica Acta, 354, (2020), 136610.
[4] Vernickaite, E., Bersirova, O., Cesiulis, H., Tsyntsaru N., “Design of highly active electrodes for hydrogen evolution reaction based on Mo-rich alloys electrodeposited from ammonium acetate bath”, Coatings, 2019, 9(2), p.85.
[5] Kuznetsov, V.V., Gamburg, Yu.D., Zhulikov, V.V., Batalov, R.S., Filatova, E.A.,“Re-Ni cathodes obtained by electrodeposition as a promising electrode material for hydrogen evolution reaction in alkaline solutions”, Electrochimica Acta, 317, (2019), pp.358-366.