Evaluation of Electric Properties for Niobium Capacitors

Abstract

In order to evaluate the applicability of niobium powder, which was manufactured by the external continuous supply method, as a capacitor, the present study measured capacitor performance evaluation factors such as leakage current, permittivity loss (tan δ), capacitance, impedance, equivalent series resistance, etc. Capacitance decreased significantly from 156μF in electrolyte (wet cap) to 130 μF after carbon (C)/silver (Ag) solution coating, and around 105 μF after aging, falling within the capacity tolerance of tantalum capacitors. If capacitance was converted to CV/g, it was around 81,000CV/g. Permittivity loss (tan δ) decreased significantly from 12.9% after C/Ag coating to 7.7% after aging, satisfying the general standard level of 10% or less. Leakage current was 2.41 μA after C/Ag coating and 2.93 μA after aging, both less than the standard level of 6.3 μA. As a whole, the niobium capacitor showed somewhat more unstable characteristics than commercial tantalum capacitors but can be considered applicable as a substitute for tantalum capacitors in the future.