Dissociation of metal oxides on surface bombardment by slow electrons: G S Loginova and A D Mikhaylova, Elektron Tekh Priemno Usilit Lampy, 1, 1970, 22–27 ( in Russian)

Abstract

The overall composition of products formed from condensed-phase reactions typically vary in a continuous fashion according to the concentrations of the initial reactant powders. In such reactions, phase changes thus play a significant role in the ability to synthesize a homogeneous product from an initially heterogeneous mixture of reactants, such as occurs in condensed reactions between metal and nonmetal powders to form nonstoichiometric homogeneous ceramics (e.g., TiCν). Here, a model is developed for such a system that allows, in turn, for melting of one of the initial components, a diffusion-limited reaction between the solid, nonmelting reactant and the molten metal to produce a solid product, melting of the solid product, and finally, reaction to completion according to a kinetics-limited rate law. As with purely homogeneous (kinetics-limited) or heterogeneous (diffusion-limited) models, the present problem, which on an overall basis incorporates both types of processes, may be analyzed in the realistic limit of large activation energies of both diffusion and reaction. This provides an asymptotic, flame-sheet type of formulation of the problem, which in turn yields an analytical expression for the steady, planar burning rate eigenvalue, and allows the explicit determination of the stability boundary that corresponds to the transition from steady to nonsteady combustion known to occur in these types of systems.