Production of Porous Tantalum Anodes for Electrolytic Capacitors Using Spot Pulsed Electric Current Sintering
Laboratory samples of plate-shaped anodes were obtained using point-by-point electric pulse sintering. These samples were made of stone-like (2.5 kCV, FTD25 grade) and agglomerated (80 kCV, FTW800 grade) tantalum powders in the air and argon environment and had sufficient strength. The results of electron microscopy showed that the samples have a developed porous structure with pore sizes from few to tens of microns. It is shown that the materials obtained can have both an almost completely homogeneous structure and a structure with a periodic density. Heat treatment and subsequent electrolytic oxidation of the samples were carried out, and their electrical characteristics were measured. It is shown that the obtained anodes have high electrical properties, which are superior to the characteristics of mass-produced anodes. An increase in the specific capacity up to 318 %, a decrease in the leakage current up to 70 %, and an increase in the breakdown voltage up to 41 % have been achieved.