AbstractAssuming isothermic atmospheres for the carbon stars, the growth and motion of silicon carbide particles were computed for a set of densities of the atmospheres. It is shown that the particles are able to escape from the atmosphere in case the surface acceleration is sufficiently low. An estimation of the whole mass of the expelled particles points out that only a small fraction of the interstellar dust can be silicon carbide. Nevertheless it is possible that these particles could act as condensation cores in the interstellar space.