Production of high-purity tantalum flake powder

Abstract

The present invention relates to a high-purity tantalum flake powder, produced by a hydride-dehydride process including: (a) cold working tantalum metal into a thin sheet; (b) hydriding the thin sheet, forming a brittle tantalum body, e.g., a foil or ribbon with an aspect ratio of greater than 5 to 1; (c) adjusting the tantalum body to a desired particle size; and (d) removing hydrogen from the tantalum body by vacuum sintering, forming a tantalum flake powder. In accordance with an embodiment of the present invention, tantalum flake is produced by sizing ultra-thin tantalum foil via the hydride-dehydride process. Tantalum is an extremely malleable metal and can be cold worked into extremely thin sheets less than 1 micron thick. Once hydrided, this foil is brittle, and can be easily sized by suitable milling processes. The hydrogen is removed by vacuum sintering, resulting in an extremely thin Ta metal flake.

1 . A high-purity tantalum flake powder, produced by a hydride-dehydride process comprising:
 (a) cold working tantalum metal into a thin sheet;   (b) hydriding the thin sheet, forming a brittle tantalum body with an aspect ratio of greater than about 5 to 1;   (c) adjusting the tantalum body to a desired particle size; and   (d) removing hydrogen from the tantalum body by vacuum sintering, forming a tantalum flake powder.   
     
     
         2 . The tantalum flake powder as recited in  claim 1 , wherein the flake is of a uniform thickness across its length. 
     
     
         3 . The tantalum flake powder as recited in  claim 1 , wherein the flake has a thicker sinter neck. 
     
     
         4 . The tantalum flake powder as recited in  claim 1 , wherein the hydriding occurs at a temperature of about 400-800° C. 
     
     
         5 . The tantalum flake powder as recited in  claim 4 , wherein the hydriding occurs at a temperature of about 600° C. 
     
     
         6 . The tantalum flake powder as recited in  claim 1 , wherein the brittle tantalum body has a thickness of about 0.5-25 μm. 
     
     
         7 . The tantalum flake powder as recited in  claim 1 , wherein the presence of contaminants in the powder is minimized. 
     
     
         8 . The tantalum flake powder as recited in  claim 1 , wherein electronic valves are produced from tantalum flake powders. 
     
     
         9 . The tantalum flake powder as recited in  claim 1 , further comprising screening the tantalum flake powder to a final particle size distribution. 
     
     
         10 . The tantalum flake powder as recited in  claim 1 , wherein the body is a foil or a ribbon. 
     
     
         11 . A method of producing tantalum flake powder which comprises:
 (a) cold working tantalum metal into a thin sheet;   (b) hydriding the thin sheet, forming a brittle tantalum body with an aspect ratio of greater than about 5 to 1;   (c) adjusting the tantalum body to a desired particle size; and   (d) removing hydrogen from the tantalum body by vacuum sintering, forming a tantalum flake powder.   
     
     
         12 . The method as recited in  claim 11 , wherein the flake is of a uniform thickness across its length. 
     
     
         13 . The method as recited in  claim 11 , wherein the flake has a thicker sinter neck. 
     
     
         14 . The method as recited in  claim 11 , wherein the hydriding occurs at a temperature of about 400-800° C. 
     
     
         15 . The method as recited in  claim 14 , wherein the hydriding occurs at a temperature of about 600° C. 
     
     
         16 . The method as recited in  claim 11 , wherein the brittle tantalum body has a thickness of about 0.5-25 μm. 
     
     
         17 . The method as recited in  claim 11 , wherein the presence of contaminants in the powder is minimized. 
     
     
         18 . The method as recited in  claim 11 , wherein electronic valves are produced from tantalum flake powders. 
     
     
         19 . The method as recited in  claim 11 , further comprising screening the tantalum flake powder to a final particle size distribution. 
     
     
         20 . The method as recited in  claim 11 , wherein the body is a foil or a ribbon.