Treatment of tantalum powder
AssigneeSprague Electric Company
InventorSidney D. Ross
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Abstract
Tantalum powder for electrolytic capacitors is treated with a non-aqueous solution of ammonium thiocyanate in N,N'-dimethylformamide or N-methylpyrrolidinone after the powder has been subjected to a thermal treatment in the absence of oxygen step and before the powder is exposed to an oxygen-containing fluid to prevent oxygen uptake by the powder. The thermal treatment step is carried out at 700.degree. C. and above.
Claims4
A process for treating tantalum powder for electrolytic capacitors comprising contacting the powder after a thermal treatment in the absence of oxygen step at 700.degree. C. and above and before exposure to an oxygen-containing fluid with a nonaqueous solution of ammonium thiocyanate in an amide solvent to passivate said powder to oxygen pickup on exposure to said oxygen-containing fluid.
Dependencies are inferred from the claim text.