Some regularities of plasma-solution synthesis of binary oxide compounds

Abstract

In this paper, we consider the preparation of some double oxides of transition metals, namely (ZnO)0.92 (CdO)0.08, NiOCuO, NiOCo2O, CoFe2O4, NiFe2O4, ZnFe2O4. The synthesis of bimetallic oxide compounds occurred in two stages. First, plasma-solution synthesis of ultrafine particles from solutions of a mixture of nitrates under the action of a DC glow discharge. The second was the high-temperature treatment of the resulting hydroxonitrates and hydroxides. The kinetics of the formation of the solid phase in the solution had an induction period associated with the accumulation of active particles in the solution under the action of the plasma and the change in the intensity of the light transmitted through the solution during the plasma treatment has an exponential decreasing character. The characteristic times of solid phase formation obtained from these dependences decrease with increasing discharge current. As a result of hydrolysis-like processes, hydroxides and hydroxonitrates of the corresponding metals were formed in the solution. This was confirmed by the XRD and EDS data. According to the data of a SEM and DLS, the particles obtained were characterized by two sizes: one was about 100 nm and the other was about 1.5 μm.