Fabrication of glass/Ni–Fe–P ternary alloy core/shell composite hollow microspheres through a modified electroless plating process

Glass/Ni–Fe–P ternary alloy core/shell composite hollow microspheres were fabricated by a modified electroless plating process. In the process, a coupling procedure was employed with 3-aminopropyltriethoxy silane as the coupling agent and silver nitrate was used as the activator. The effect of process parameters, such as mole ratio of (NH4)2Fe(SO4)2/NiSO4, pH value of the plating solution and reaction temperature, on plating rate and properties of the composite microspheres were investigated. The results showed that the coupling treatment could improve the uniformity of Ni–Fe–P deposits remarkably. The plating rate was reduced rapidly with the increase of mole ratio of (NH4)2Fe(SO4)2/NiSO4. The increase of the pH value could enhance the plating rate and the percentage of iron in the deposits. The as-obtained microspheres were magnetically soft at room temperature and their magnetic properties got better with the enhancement of the percentage of iron in the deposits.