Process for producing ultra-fine ceramic particles
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKazuhide Ota, Susumu Abe
Life of this patent
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Abstract
A process for producing ultra-fine ceramic particles with the particle size of less than 1000 .ANG., which comprises the steps of forming powdered dust cloud of metal powder such as Si constituting a portion of aimed ceramic particles in a reaction gas containing the other portion of said aimed ceramic particles, igniting said powdered dust cloud to cause explosive burning and synthesizing said aimed ceramic particles and gathering said resulting ceramic particles. By the process, ceramic particles such as Al.sub.2 O.sub.3, MgO, SiO.sub.2, TiO.sub.2, TiN having particle size of 10-100 nm can be produced.
Claims25
A process for producing ultra-fine ceramic particles which comprises:
- (a) forming a powdered dust cloud composed of metal powder and a reaction gas containing an element for reaction with said metal powder,
- (b) igniting the same to cause explosive burning and synthesizing the ultra-fine ceramic particles, and
- (c) gathering said ultra-fine ceramic particles;
- and wherein the reaction enthalpy, .DELTA.H.sub.0, is sufficiently large to generate sufficient heat to evaporate the metal, thereby causing an explosion of the powdered dust after ignition, and wherein the value T, which is the value obtained by dividing the temperature T.sub.0 (.degree.K.) at the free energy of th product .DELTA.G.sub.0 -0 by the boiling point T.sub.1 (.degree.K.) of the constituent metal of the product, is greater than 0.6, indicating that the reaction product is stable at the reaction temperature.
A process for producing ultra-fine oxide particles, which comprises:
- (a) forming a chemical flame containing gaseous oxygen;
- (b) feeding metal powder into said chemical flame to explosively burn said metal powder and to synthesize the ultra-fine oxide particles;
- and
- (c) gathering ultra-fine oxide particles;
- and wherein the reaction enthalpy, .DELTA.H.sub.0, is sufficiently large to generate sufficient heat to evaporate the metal, thereby causing an explosion of the powdered dust after ignition, and wherein the value T, which is the value obtained by dividing the temperature T.sub.0 (.degree.K.) at the free energy of the product .DELTA.G.sub.0 -0 by the boiling point T.sub.1 (.degree.K.) of the constituent metal of the product, is greater than 0.6, indicating that the reaction product is stable at the reaction temperature.
Dependencies are inferred from the claim text.