Preparation of (Ni–B)/SiO2, Ni/SiO2 and NiO/SiO2 nanocomposites

In this work we report composites of nickel–boron (Ni–B)/SiO2, Ni3B/SiO2, Ni/SiO2 and NiO/SiO2. As precursor of the nickel compounds, we used nanometric amorphous Ni–B alloy particles. The nanometric Ni–B particles were prepared by aqueous chemical reduction and studied by transmission electron microscopy (TEM), differential thermal analysis (DTA) and X-ray diffraction (XRD) before their incorporation into the SiO2 xerogel. The composite samples were prepared by the sol–gel method. The produced samples were ground to form powders, heat treated at different temperatures under atmospheric conditions and characterized by TEM, XRD and DTA techniques. A specific composite (Ni3B/SiO2, NiO/SiO2, Ni/SiO2, (Ni–B)/SiO2) can be produced depending on the temperature used for reaction. Composites were stable at room temperature and there were no significant phase transformations under aging.