This paper concerns the microscopic dynamical description of competing meta
stable states. We study, at infinite volume and very low temperature, metas
tability and nucleation for kinetic Blume-Capel model: a ferromagnetic latt
ice model with spins taking three possible values: -1, 0, 1. In a previous
paper ([MO]) we considered a simplified, irreversible, nucleation-growth mo
del; in the present paper we analyze the full Blume-Capel model. We choose
a region U of the thermodynamic parameters such that, everywhere in U: -(1)
under bar (all minuses) corresponds to the highest (in energy) metastable
state, 0 (all zeroes) corresponds to an intermediate metastable state and (1) under bar (all pluses) corresponds to the stable state, We start from -
(1) under bar and look at a local observable. Like in [MO], we find that, w
hen crossing a special line in U, there is a change in the mechanism of tra
nsition towards the stable state +(1) under bar. We pass from a situation.
1. where the intermediate phase (0) under bar is really observable before t
he final transition, with a permanence in (0) under bar typically much long
er than the first hitting time to (0) under bar to the situation:
2. where (0) under bar is not observable since the typical permanence in (0
) under bar is much shorter than the first hitting time to (0) under bar an
d, moreover, large growing 0-droplets are almost full of +1 in their interi
or so that there are only relatively thin layers of zeroes between +1 and -
1.