We address the problem of crystallization, melting and evaporation of
dust particles in disks around YSOs. This problem has attracted much
interest in recent years since it is one important feature which gives
considerable insight into evolutionary processes in such disks that is
accesible to observations with the new generation of large
telescopes. Shock waves seems to be the mechanism able to explain the
formation of crystalline silicates found in chondrites, long-period
comets, and disks around YSOs (Jones et al. 2000, Protostars and
Planets IV, 927; Scott and Krot 2004, ApJ in press). We propose a new
energy source of gas dynamics shocks based on gravitational
perturbations excited by a companion object, i.e., a giant planet or a
companion star. We carry out a parameterization of the wave dynamics
and of the dust heating in the shock front that predicts the melting
and/or evaporation of silicates in bound orbital ranges determined by
the companion parameters. We obtain that the gravitational
perturbations of the companion would generate shock waves able to
process dust particles at 1-5 AU depending on the central star and
disk physical parameters as well as on the companion parameters
(Parisi and Sterzik 2005 submitted to 
). We especulate that the
precense and abundance of crystalline and amorphus silicate grains in
young binary systems (young brown dwarfs, T-Tauri stars, and Herbig
AeBe stars) are determined by this process. Current infrared
observations are just approaching the necessary precision to test this
hypothesis.