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 Ta 2O 5– 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.