Vapor phase synthesis of high purity nano- and submicron particles with controlled size and agglomeration

摘要

PURPOSE: Provided is a simple method for preparing nano/submicron-sized particles with high purity, low agglomeration and high crystallinity by vapor phase synthesis which is characterized by cutting the reaction area with cold fluid. CONSTITUTION: The preparation method of nano/submicron-sized ceramic, metal, and alloy particles by vapor phase synthesis using a flame reactor comprises the steps of: (i) preparing a vapor or aerosol phased precursor by heating of an evaporator, wherein the precursor is selected from metal, BCl3, boric acid ester, metal halide, metal hydroxide, etc.; (ii) carrying the prepared precursor mixed with carrier gas(Ar, N2) into the central tube(12a) of a flame reactor(12) containing four tubes in concentric circles(12a-d), wherein the fuel gas(H2 or hydrocarbon) is flown into the second tube(12b), the reactant gas(O2, H2 or hydrazine) is flown into the third tube(12c) to make flames, and the stabilizing gas(air) is flown into the fourth tube(12d); heating the mixture of precursor and gas in a reaction area of the flame reactor with fuel gas to synthesize nano-sized particles; (iii) controlling the reaction area forming particles by spraying cold fluid(4) such as inert gas, air, water or solvent on a special position of the reaction area strongly through a reaction- stopping device(6), which leads particles to be formed under the spray area when the primary nano particles are growing, and unagglomerated primary particles are agglomerated to be secondary particles; (iv) gathering prepared nano/submicron-sized particles. Also, the nano/submicron-sized particles are prepared by vapor phase synthesis using a thermal reactor in which the prepared precursors mixed with carrier gas or reactant gas are carried at the step (ii).