A niobium powder for a capacitor having a tapping density of 0.5 to 2.5 g/ml,
and
average particle size of 10 to 1000 mum, angle of repose form 10 to
60, the BET specific surface area from 0.5 to 40 m2/g and a plurity
of pore diameter peak tops in the pore distribution, and a producing method therof;
(2) a niobium sintered body, which is obtained by sintering the above niobium powder
and, having a plurality of pore diameter peak tops in a range of 0.01 mum
to 500 mum, preferably, the peak tops of two peaks among the plurality of
pore diameter peak tops having a highest relative intensity are present in the
range of 0.2 to 0.7 mum and in the range of 0.7 to 3 mum, respectively,
and a producing method thereof; (3) a capacitor using the above sintered body and
a producing method thereof, and (4) an electronic circuit and electronic device
using the above capacitor.
