Fundamentals of the thermochemical kinetics of heterogeneous processes in reacting powder systems

Abstract

The modern notions of nonequilibrium thermodynamics, synergetics, and thermokinetics of synergy in reacting powder systems underlie the thermochemical kinetics of heterogeneous processes. The kinetic aspect of synergy is associated with local interaction in a gaseous or liquid medium with the maximum degrees of freedom. A liquid or gaseous region in a reacting powder system is regarded as a flow reactor. Applications of the thermochemical kinetics of heterogeneous processes are shown.The key task in modern natural science is to study the irreversible processes in nonequilibrium physicochemical systems and dynamics of collective interaction mechanisms that give rise to organized matter. This is an interdisciplinary task that contributes to the development of fundamental problems of science and technology. The fundamental and applied aspects are associated with the potential of nonequilibrium processes and their typical nonlinear interaction to differentiate energy and matter and linearly concentrate and accumulate flows of dissipated energy. Objects of flora and fauna are an example of this behavior, in which internal processes ensure the performance of the system with the minimum entropy function due to complex hierarchic organization originating from the highest form of nonlinear interaction⎯self-organization processes [1, 2]. The nonlinear interaction processes precede self-organization and originate from collective interaction. It is powder inorganic systems where physicochemical interaction processes show their collective nature [3,4]. Their study will obviously reveal the main mechanisms that lead to the differentiation of matter and energy. Despite the complexity of nonlinear interaction processes, inorganic systems are the simplest, and hence the main mechanisms that give rise to self-organization processes may be found out. In addition, heterogeneous reacting systems based on powder agents are perfect models for simulating irreversible processes to establish general collective laws of evolution in nonequilibrium physicochemical systems in which dissipative structures form, and, finally, to reveal the nature of dissipative forms or objects [5,6].Noteworthy is the rapidly increasing number of papers in materials science [7,8] devoted to selforganization. However, most of them are just descriptive.Besides the fundamental aspect, the mechanisms of nonequilibrium processes in reacting powder systems are primarily of applied interest for developing materials of new generation with nonlinear adaptation mechanisms [6,9,10]. The irreversibility of heterogeneous interaction processes gives rise to numerous new phenomena of

Complex Protective Coatings for Graphite and Carbon-Carbon Composite Materials

“…In this case it is supposed that the single components (carbon and tungsten), participating in chemical reactions during the protective coating formation, are in solid state while the rest components are in liquid or vapor state. Recently a series of articles have been published in the literature [25]- [27]. There discussed are rather complicated problems of theory for thermomechanical kinetics of heterogeneous processes in the powder reactive systems.…”

Collective processes in liquid-phase reaction sintering

“…That is, there are several thermochemical paths that determine both the kinetic variations in temperature and the structure of the reaction system itself. It was ascertained experimentally [12]. If the structural variation is significant, the rheological behavior of a reaction system will substantially depend on the thermochemical path of the process.…”