Effect of Addition of Potassium Carbonate to Aluminum Powder on the Grain Size of Al2O3 Nanoparticles Formed in the Laminar Dusty Flame
N. I. Poletaev, Yu. A. Doroshenko
Keywords: aluminum flame, gas-disperse synthesis, readily ionized additives, grain size of combustion products, coagulation rate, dusty plasma
Abstract
Results of studying the effect of K2CO3 additives on the grain size of the products of combustion of a gas suspension of Al particles (with the mean particle diameter of 4.8 mm) in a laminar diffusion flame are reported. An extreme character of the dependence of the mean size of Al2O3 particles on the additive concentration is experimentally observed. For the concentration of the K2CO3 additive equal to 0.5%, the mean diameter of Al2O3 particles is 30 nm; for the additive concentration of 5%, the mean particle size increases to 67 nm. It is demonstrated that the change in the mean size of A2O3 particles as a function of the concentration of the readily ionized additive is caused by interaction of the dusty and ionic subsystems of the plasma of the combustion products in the reaction zone in the flame. At a high concentration of ions (above 1020 m-3), this interaction increases the rate of coagulation of Al2O3 particles.
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