Combustion synthesis-derived tantalum powder for solid-electrolyte capacitors

In this paper, the synthesis of capacitor-grade tantalum (Ta) powder via the self-propagating high-temperature synthesis (SHS) method is described. In addition, the sintering aspects and electrical characteristics of the powder are discussed. Ta powder was prepared via the combustion of a Ta2O5-xMg-kNaCl mixture, under argon pressure. The morphology and size of the final powder particles was controlled by adjusting the Mg-NaCl concentration. The final powder particles had nodular shapes and sizes ranging from 0.1 to 0.5 μm. A leakage current of a sintered Ta sample containing the smallest particle size was 10 μA; its capacitance was 92,738 CV, when a 40-V voltage was applied to the sample.