METAL POWDER PRODUCED BY THE REDUCTION OF OXIDE WITH GASEOUS MAGNESIUM

摘要

PROBLEM TO BE SOLVED: To provide a process for the manufacture of alloy powder for an electrolytic capacitor composed of niobium and tantalum.

SOLUTION: A process for the manufacture of alloy powder to be used in the manufacture of an electrolytic capacitor comprising the steps of: (a) hydriding an electron-beam melted alloy ingot containing Nb and up to 40 at.% Ta based on the total content of Nb and Ta; (b) comminuting the hydrided alloy ingot; (c) dehydriding the comminuted alloy obtained from step (b); (d) forming the comminuted alloy into flakes; (e) agglomerating the flake at a temperature of 800 to 1,150°C in the presence of an alkali earth metal as a reducing agent; and (f) leaching and washing the agglomerated alloy flakes to remove any residual and residual product of the reducing agent. The alloy powder consists essentially of tantalum of up to 40 at.% based on the total content of Nb or Nb and Ta and lies in the form of agglomerated flakes having a product of BET surface area and alloy density of 8 to 45 (m2/g)×(g/cm3).

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