Thermodynamic Modeling of Plasmochemical Process of Synthesis of Dispersed Metal Oxides

Abstract

Nowadays plasmochemical synthesis is one of the widespread methods of producing powders that allows finely dispersed materials with required structure and uniform distribution of components to be synthesized. To develop a reliable and effective plasmochemical reactor, a comprehensive study of the processes proceeding in it is required, and as a consequence, their thermodynamic modeling is necessary. Thermodynamic calculation of the equilibrium structure of cerium and yttrium nitrate decomposition products in plasma is complicated by the fact that the gas phase is multicomponent, and various processes with formation of atoms and radicals can proceed in plasma; in addition, the processes of restoration of originally formed ions proceed at high temperatures in plasma. In this regard, thermodynamic modeling by computer programs is often used to determine the composition of components and the system properties. The universal program TERRA intended for calculation of multicomponent heterogeneous systems [1] was used for thermodynamic analysis of plasmochemical process of producing cerium and yttrium oxides. The program TERRA of thermodynamic calculations is based on the principle of maximum entropy for isolated thermodynamic systems in equilibrium state. It possesses its own base of thermodynamic properties of individual substances. The base is constantly updated and refined. Nowadays the thermodynamic functions for 3500 individual substances at temperatures in the range 300–6000 K are contained in the databank.