Аннотация:Composite materials comprised of a ceramic matrix with metal-containing nanoparticles were prepared by sintering iron (II) oxalate and polycarbosilane. The chemical composition of the material can be controlled by a sintering process. Sintering in inert atmosphere leads to reduction of the sample and metal iron formation (a-Fe, carbide). Formation of iron oxides requires calcination procedure in series (argon and air) for removing by products. The air-sintering materials consist mainly of oxide phases, but also contain metal iron. The prepared samples were characterized by the: SEM, TEM, XRD and EMR techniques and the Mössbauer spectroscopy. It was shown unique behavior that iron containing particles after calcination in air decreased from 5-30 nm to 2–5 nm due to interaction with matrix under air atmosphere.