Abstract:
A theoretical approach to consider formation of
chemical compound layer at the interface between initial substances
A and B due to the interfacial interaction and diffusion is developed.
It is considered situation when speed of interfacial interaction is large
enough and diffusion of A-atoms through AB-layer is much more then
diffusion of B-atoms. Atoms from A-layer diffuse toward B-atoms
and form AB-atoms on the surface of B-layer. B-atoms are assumed to
be immobile. The growth kinetics of the AB-layer is described by two
differential equations with non-linear coupling, producing a good fit
to the experimental data. It is shown that growth of the thickness of
the AB-layer determines by dependence of chemical reaction rate on
reactants concentration. In special case the thickness of the AB-layer
can grow linearly or parabolically depending on that which of
processes (interaction or the diffusion) controls the growth. The
thickness of AB-layer as function of time is obtained. The moment of
time (transition point) at which the linear growth are changed by
parabolic is found.
