Characterization of electrodeposited powders of the system Ni–Mo–O

The electrodeposition of the Ni–Mo–O alloy powders from ammonium chloride containing electrolytes for different Ni/Mo ions concentration ratios was investigated by the polarization measurements. The morphology, chemical composition and phase composition of the electrodeposited Ni–Mo–O alloy powders were investigated using DSC, TGA, SEM, EDS and XRD analysis. According to the EDS results, the powder composition depends on the Ni/Mo ions concentration ratio. However, some deviations in the composition of the as-deposited powders, as the result of the position of the EDS analysis, revealed that the composition of such powders is not homogeneous. The as-deposited alloy powders were nanocrystalline showing only one broad XRD peak around 44°. Their morphology was found to depend on the Ni/Mo ions concentration ratio. After annealing of the Ni–Mo–O powders for 2 h in N2 atmosphere at 600 °C, well-defined crystals for all powders were detected by SEM. The presence of the NiMoO4 phase only or NiMoO4 and MoO3 phases in these powders (XRD), depending on the Ni/Mo ions concentration ratio, was identified. The additional EDS analysis on different recrystallized grains revealed the influence of the annealing on a composition of the alloy powders.