Nioobiumi- ja tantaalinanopulbrite tootmine

Abstract

Niobium and tantalum powders used in modern manufacturing are materials with nanostructure. The authors have studied and optimized the process of the production of niobium and tantalum nanopowders (adjusted in the range of the particle size of 20-150 nm) at pilot scale. The process is based on the reduction reaction of pentachlorides of tantalum and niobium with hydrogen in a plasma generator at about 3500 K. To stabilize the structure and adjust the granulometric composition of the produced nanopowders thermal treatment at 1373 K under vacuum was applied. The powders are characterized by very high purity with regard to oxygen and metallic admixtures and by low bulk density (0.1-0.3 g/cm 3). The specimens had a high specific surface area (10-30 m 2/g). The process of compacting and sintering of powders was tested at temperatures from 1173 to 1373 K. The porosity of the specimens was 0.55-0.75 from the theoretical. The pore diameter was adjusted to 0.5-0.05 μm.