  Dewetting of a binary alloy thin film is studied using a continuum
many-parameter model that accounts for the surface and bulk diffusion, the bulk
phase separation, the surface segregation and the particles formation.
Analytical solution is found for the quasistatic equilibrium concentration of a
surface-segregated atomic species. This solution is factored into the nonlinear
and coupled evolution PDEs for the bulk composition and surface morphology.
Stability of a planar film surface with respect to small perturbations of the
shape and composition is analyzed, revealing the dependence of the particles
size on major physical parameters. Computations show various scenarios of the
particles formation and the redistribution of the alloy components inside the
particles and on their surface. In most situations, for the alloy film composed
initially of 50% A and 50% B atoms, a core-shell particles are formed, and they
are located atop a wetting layer that is modestly rich in the B phase. Then the
particles shell is the nanometric segregated layer of the A phase, and the core
is the alloy that is modestly rich in the A phase.
