An attempt to produce NiFe2O4 powder from electrodeposited Fe-Ni alloy powders by subsequent recrystallization in air

Abstract

The electrodeposition of the Fe-Ni powders from citrate-ammonium chloride containing electrolytes for different Ni/Fe ions concentration ratios at pH 4.0 was investigated by the polarization measurements. The morphology, chemical composition, and phase composition of the obtained powders were investigated using SEM, EDS, and XRD analysis. EDS analysis of as-deposited alloy powders confirmed anomalous co-deposition of Fe and Ni. A common characteristic for all as-deposited powder samples was the presence of cone-shaped cavities and nodules on the big agglomerates of the order of 200-400 mu m. After annealing in air at 400, 600, and 700 A degrees C for 3 h, all alloy powders oxidized forming NiO, NiFe2O4, and Fe2O3 phases in different proportions depending on the original powder composition. The NiFe2O4 phase was found to be dominant in the sample with the highest percentage of Fe after annealing at 600 A degrees C.