Extended characteristics of dispersed composition for nanopowders of plasmachemical synthesis

Abstract

With the help of a complex of methods of disperse-structure analysis of nanopowders of plasmachemical synthesis, the function of particle-size distribution and its main characteristics—the average size and dispersion—are studied. A generalization of results of disperse characteristics for nanoparticles formed with the participation of various mechanisms—“vapor–solid” and “vapor–liquid–solid”—is carried out. It is shown that the formation of titanium nitride and carbonitride nanoparticles proceed on the vapor–solid mechanism without the participation of coagulative-particle growth. For the nanopowders under study, it is established that the variation range of standard deviation for the distribution function is in the interval of 30–60% of the average diameter; the index of aggregation is defined in the range of 1.5–3.0. It is revealed that the logarithmically normal function of particle-size distribution most authentically (with a correlation coefficient of more than 0.95) describes all studied objects for all mechanisms of particle formation in a wide range of dispersion of the received nanopowders independently of process parameters and organization of gas-disperse stream in the plasma reactor. Hypothetically, the established lognormal particle-size distribution is determined by the lognormal distribution of nanoparticles by residence time in the growth zone.