Method for preparing metal powder

Abstract

A method for preparing a highly crystallized metal powder, comprising: supplying at least one heat-decomposable metal compound powder into a reaction vessel using a carrier gas; and forming a metal powder by heating the metal compound powder in a state in which the metal compound powder is dispersed in a gas phase at a concentration of no more than 10 g/liter, at a temperature that is over the decomposition temperature of the metal compound powder and at least (Tm−200)° C. when the melting point of the metal contained in the metal compound powder is Tm° C. The method provides a high-purity, high-density, highly dispersible, fine, highly crystallized metal powder consisting of spherical particles of uniform size, which is suited to use in thick film pastes, and particularly conductor pastes and the like used in the preparation of multilayer ceramic electronic parts.

What is claimed is:  
     
         1 . A method for preparing a highly crystallized metal powder, comprising: 
 supplying at least one heat-decomposable metal compound powder into a reaction vessel using a carrier gas; and    forming a metal powder by heating the metal compound powder in a state in which the metal compound powder is dispersed in a gas phase at a concentration of no more than 10 g/liter, at a temperature that is over the decomposition temperature of the metal compound powder and at least (Tm−200)° C. when the melting point of the metal contained in the metal compound powder is Tm° C.    
     
     
         2 . The method for preparing a highly crystallized metal powder according to  claim 1 , wherein the metal compound powder is a homogeneous mixed powder or a composite powder of a metal compound or compounds including two or more metal elements, and the metal powder is an alloy powder.  
     
     
         3 . The method for preparing a highly crystallized metal powder according to  claim 1 , wherein the carrier gas is an inert gas, and the metal powder is nickel powder, copper powder, or an alloy powder containing nickel and/or copper.  
     
     
         4 . The method for preparing a highly crystallized metal powder according to  claim 1 , wherein a metal compound powder which brings the atmosphere during pyrolysis to a reducing atmosphere by being pyrolyzed in an inert gas is used as the metal compound powder.  
     
     
         5 . The method for preparing a highly crystallized metal powder according to  claim 4 , wherein the metal compound powder is a metal carboxylate powder.  
     
     
         6 . The method for preparing a highly crystallized metal powder according to  claim 1 , wherein the metal powder is a palladium powder or an alloy powder containing palladium.  
     
     
         7 . A highly crystallized metal powder prepared by the method according to  claim 1 .  
     
     
         8 . A conductor paste containing the highly crystallized metal powder according to  claim 7 .  
     
     
         9 . A multilayer ceramic electronic part in which a conductor layer is formed using the conductor paste according to  claim 8.