Direct Electrochemical Preparation of Ni-Zr Alloy from Mixture Oxides in LiCl Molten Salt

The Ni5Zr alloy prepared from the mixture of nickel oxide (NiO) and zirconium oxide (ZrO2) powders by direct electrochemical reduction was conducted in molten lithium chloride (LiCl) at 923 K. The electrochemical reduction behaviors of ZrO2 and NiO-ZrO2 mixture were firstly investigated by cyclic voltammetry measurements. The influence of process parameters such as oxide composition, compression force, sintering time, and cell voltage on the electrolysis process have been comprehensively evaluated in terms of the electrochemical reducibility of ZrO2. The results demonstrated that the reduction starts with the reduction of NiO to Ni metal, and is followed by the reduction of ZrO2 on the pre-formed Ni particles to generate the intermetallic Ni5Zr. The pure Ni5Zr alloy can be prepared by direct electrochemical reduction of mixed 5NiO-ZrO2 pellets when the cell voltage of 3.2 V is applied. The reduction rate increases with higher content of NiO in a NiO-ZrO2 mixture pellet. However, the quality of formed Ni5Zr intermetallic compound particle seems unaffected under different preparation conditions. (c) 2017 The Electrochemical Society. All rights reserved.