Method for producing fine tungsten powder

Abstract

A method for finely powdering tungsten powder, which includes dispersing tungsten powder in an aqueous solution containing an oxidizing agent to form an oxide film in the surface of the tungsten powder and removing the oxide film with an alkaline aqueous solution. Also disclosed is a method for producing fine tungsten powder, which includes obtaining tungsten powder having an average particle size of 0.05 to 0.5 μm by a process including the above method for finely powdering. Also disclosed is a tungsten powder having an average particle size of 0.05 to 0.5 μm, in which the dMS value (product of an average particle size d (μm), true density M (g/cm 3 ) and BET specific surface area S (m 2 /g)) is within the range of 6±0.8.

1 . A tungsten powder having an average particle size of 0.05 to 0.5 μm, in which the dMS value (product of an average particle size d (μm), true density M (g/cm 3 ) and BET specific surface area S (m 2 /g)) is within the range of 6±0.8. 
     
     
         2 . The tungsten powder as claimed in  claim 1 , in which the dMS value is within the range of 5.4 to 5.8. 
     
     
         3 . The tungsten powder as claimed in  claim 1 , in which the average particle size is 0.4 to 0.5 μm. 
     
     
         4 . The tungsten powder as claimed in  claim 3 , in which the dMS value is within the range of 5.4 to 5.8.