Electrochemical Preparation of ZrFe2 and ZrFe1.8Ni0.2 Intermetallic Compounds by FFC Cambridge Process

Abstract

The aim of the present study was to prepare ZrFe2 and ZrFe1.8Ni0.2 intermetallic compounds by FFC Cambridge process. The intermetallic compounds were prepared directly from the mixed oxide precursors, namely ZrO2-Fe2O3 and ZrO2-Fe2O3-NiO, respectively. Electrochemical de-oxidation experiments were carried out with mixed oxide pellet cathode and HD graphite anode by applying a constant cell voltage of 3.1 V in CaCl2 melt at 900 oC. The electrochemical behaviour of oxides was studied by cyclic voltammetry using metallic cavity electrodes (MCEs). The electrolysis was carried out for different durations of time to understand the mechanistic pathway of reduction of ZrO2-Fe2O3. The electro-reduced products were characterized by X-ray diffraction (XRD) technique, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The reduction intermediates involved Fe, CaZrO3, calcia stabilised zirconia (CSZ), Fe23Zr6, Zr6Fe3O and Zr2Fe. Single cubic C15 phase of ZrFe2 was obtained in 48 h electrolysis product. ZrFe1.8Ni0.2 was also electrochemically synthesized from its oxide precursors viz. ZrO2, Fe2O3 and NiO. Apart from ZrFe1.8Ni0.2 phase, the electro-reduced products had a Zr2Ni phase even after 72 h of electrolysis.