A new model for carbon nanoparticle formation in the pyrolysis process behind shock waves

A new conceptual model for carbon nanoparticle formation in shock waves that is based on recent data of the temperature dependence for finite sizes of resulting particles and an abrupt increase in their refractive index during the change in particle sizes from 5 to 15 nm. The model is based on the two following physically distinct assumptions. First, the volumetric fraction of condensed carbon remains constant from complete decomposition temperatures for the initial carbon-containing molecules (1600–2000 K) up to evaporation temperature for carbon nanoparticles (3000–3500 K). Second, the surface growth rate for particles is determined by the rate of collisions between vapor molecules and particles. The proposed model allows an explanation of all observed regularities of the carbon nanoparticle growth, including a decrease in finite sizes of particles at a rise in temperature and a corresponding decrease in the time of particle formation.