Computational study is carried out to clarify the growth mechanisms and the effects of the silicon fraction in precursor on the fabricated nanopowders for metal-silicon binary systems (Co-Si, Mo-Si, and Ti-Si systems) under a thermal plasma condition, using a model that can simulate the collective and simultaneous combined processes of binary homogeneous nucleation, binary heterogeneous co-condensation, and coagulation among nanoparticles with different compositions as well as solidification temperature depression. Those three systems that have different ratios of the materials' saturation pressures show different growth behaviors and mature states of the nanopowders. Furthermore, parametric studies indicate that the majority of the fabricated nanoparticles have the silicon content identical to the initial precursor's silicon fraction. Because the solidification temperature depends on the silicon content in the material, the yield and size of the nanopowder are also affected indirectly by the precursor's silicon fraction. (C) 2015 Elsevier B.V. All rights reserved.