US2008011124A1PendingUtilityA1

Deoxidation of Valve Metal Powders

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Assignee: STARCK H C GMBH CO KGPriority: Sep 8, 2004Filed: Aug 26, 2002Published: Jan 17, 2008
Est. expirySep 8, 2024(expired)· nominal 20-yr term from priority
Inventors:Josua LöffelholzUlrich Bartmann
H01G 9/0525C22B 34/24B22F 9/22C22B 5/04H01G 9/15C22B 5/12
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Claims

Abstract

Deoxidation of valve metal powders, in particular of niobium powders, tantalum powders or their alloys, by treating the valve metal powder with calcium, barium, lanthanum, yttrium or cerium as deoxidising agent, and valve metal powders that are distinguished by a ratio of the sum of the contents of sodium, potassium and magnesium to the capacitance of less than 3 ppm/10,000 μFV/g.

Claims

exact text as granted — not AI-modified
1 - 10 . (canceled)  
   
   
       11 . A process for the deoxidation of valve metal powders which comprises deoxidizing valve metal powders with a deoxidizing agent, wherein the deoxidizing agent is calcium, barium, lanthanum, yttrium or cerium.  
   
   
       12 . The process according to  claim 11 , wherein the valve metal powder is a niobium powder, a tantalum powder or a niobium-tantalum alloy powder.  
   
   
       13 . The process according to  claim 11 , wherein the deoxidizing agent is calcium or lanthanum.  
   
   
       14 . The process according to  claim 11 , wherein the deoxidizing agent is calcium and the deoxidation is carried out at a temperature of from 880 to 1050° C.  
   
   
       15 . The process according to  claim 11 , wherein the deoxidizing agent is lanthanum and the deoxidation is carried out at a temperature of from 940 to 1150° C.  
   
   
       16 . The process according to  claim 12 , wherein the deoxidizing agent is calcium and the deoxidation is carried out at a temperature of from 880 to 1050° C.  
   
   
       17 . The process according to  claim 12 , wherein the deoxidizing agent is lanthanum and the deoxidation is carried out at a temperature of from 940 to 1150° C.  
   
   
       18 . The process according to  claim 11 , wherein the deoxidation is carried out in two steps.  
   
   
       19 . The process according to  claim 11 , wherein the valve metal powder obtained by reduction of a valve metal oxide with gaseous calcium, barium, lanthanum, yttrium or cerium is deoxidised.  
   
   
       20 . A valve metal powder which comprises the ratio of the sum of the impurities sodium, potassium and magnesium to the capacitance of the valve metal powder is less than 3 ppm/10,000 μFV/g.  
   
   
       21 . The valve metal powder according to  claim 20 , wherein the ratio of the sum of the impurities sodium, potassium and magnesium to the capacitance of the valve metal powder is less than 1 ppm/10,000 μFV/g.  
   
   
       22 . The valve metal powder according to  claim 20 , wherein the valve metal powder is a niobium powder.  
   
   
       23 . The valve metal powder according to  claim 20 , wherein the valve metal powder is a tantalum powder.  
   
   
       24 . The valve metal powder according to  claim 21 , wherein the valve metal powder is a niobium powder.  
   
   
       25 . The valve metal powder according to  claim 21 , wherein the valve metal powder is a tantalum powder.

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