1070-4272/04/7703-0364C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 3, 2004, pp. 364!368. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 3,
2004, pp. 370!374.
Original Russian Text Copyright C 2004 by Ksandopulo, Baidel’dinova.
AND INDUSTRIAL INORGANIC CHEMISTRY
Combustion in a System of Conjugated Layers
and High-Temperature Synthesis of Materials
G. I. Ksandopulo and A. N. Baidel’dinova
Plamya Research and Production Association, Almaty, Kazakhstan
Institute of Combustion Problems, Almaty, Kazakhstan
Received August 29, 2002; in final form, July 2003
Abstract-The possibility of constructing layered systems for high-temperature synthesis of materials is
demonstrated. The cases of vertical and horizontal arrangement of layers, which ensure different types of
a technological combustion of the initial reactant mixtures with or without subsequent interaction of the
reaction products formed, are considered. The conditions are found for the synthesis of alkaline-earth metal
titanates and aluminum borides in the layered systems.
The temperature of the combustion wave front in
metal3oxide systems may be as high as (334) 0 10
under quasi-adiabatic conditions. In order to perform
a high-temperature synthesis, conditions of this kind
can be created if the mixture of reacting components
is formed as a layer receiving thermal energy from
the side of parallel energy-carrying layers .
A stack of layers selected with account of the task
to be accomplished is arranged horizontally or ver-
tically (perpendicularly to the horizontal or vertical
axis, respectively). In some cases, it can be subjected
to the action of a centrifugal force, or an electric or
a magnetic field.
This article is concerned with the fundamental
aspects of combustion of complex stacks in relation to
the mutual arrangement of the constituent layers, their
orientation, etc. It is not aimed to establish a strict
relationship between the kinetic parameters that
govern the chemical process and the parameters deter-
mining the removal of heat from the reaction zone.
The goal is to consider the phenomenology of com-
bustion in the layers and the propagation of the com-
bustion front in the adjacent layers.
Combustion of a horizontal stack of layers. In
the horizontal variant, when the layers are arranged
perpendicularly to the horizontal axis (Fig. 1a), the
products formed in combustion of oxide system and,
in particular, reduced metals, do not penetrate into the
adjacent layers. In this case, only conductive heat
transfer occurs, since the horizontal stack is composed
of chemically independent layers. To ensure a quasi-
adiabatic course of the process in the layered system,
ignition is performed simultaneously in the adjacent
layers. Then the synthesis layers can be repeatedly
alternated with the layers that serve as sources of heat,
with the maximum heating achieved.
The macrokinetics of combustion in a layer is
determined not only by the reactant concentrations,
temperature, and pressure, but also by external forces,
e.g., those due to centrifugal acceleration in the case
of axial rotation.
The characteristic time t of combustion of a stack
is constituted by the times t
of burning-through of all
Fig. 1. Schematic of a horizontal stack of layers. Stack:
(a) that in the general case and (b) that with a repetitive
system of three layers, in which layer no. 2 is the synthesis