Preparation and processing of metal-ceramic composite materials

The preparation of nanometer-sized Ni particles in a SiO2 matrix by three-step produce is reported. In the first step, metal-organic Ni compounds are dissolved in water and reacted with the ethylenediamine derivate H2NCH2NH(CH2)3Si(oEt)3(Et=-Ch2CH3). During this reaction, hydrosolis and ammonia-catalysed condensation of the alkoxy groups take place. After the removal of solvent, the resulting gel is dried and pyrolesyd under oxidation conditions in the second step. The last step involves the reduction of the NiO/SiO2 composite material in pure hydrogen. The as-prepared product contains homogeneously dispered Ni particles in the SiO2 matrix. Depending on the metal loading, the oxidation and reduction conditions, and on further heat treatment the particles size distrubution can be varied in a wide range.