On the Formation of a Relief on the Surface of Tantalum during Its Sintering

Structural changes in FTW60 and FTW8000 tantalum capacitor powders after sintering at different temperatures are investigated by X-ray diffraction and scanning electron microscopy. Sintering is carried out in accordance with the current technological process used in the production of oxide–semiconductor capacitors. The anodes obtained as a result of sintering are bulk-porous bodies in the form of a rectangular parallelepiped with a wire lead. On the free surface of the bulk-porous anodes obtained by sintering the FTW60 powder at temperatures of 1800°C and 1920°C, the formation of a wavy relief is observed. No such relief is observed after sintering the FTW800 powder at 1250°C. After analyzing the structural state and the morphology of the initial powders and the anodes obtained as a result of sintering, a phenomenological model of the formation of such a relief is proposed based on collective recrystallization near the free surface during high-temperature exposure.