Effect of the conditions of sintering W-Ni-Fe-Co heavy alloy nanopowders on the structure and density of compacted samples

• Published in: Russian metallurgy Metally 2007-12, Vol.2007 (6), p.499-505, Article 499
• Main Authors: Povarova, K. B., Alymov, M. I., Gavrilin, O. S., Drozdov, A. A., Evstratov, E. V., Kachnov, A. I., Sal’ko, A. E.
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Density; Grain size; Liquid phase sintering; Nanocomposites; Nanomaterials; Nanostructure; Sintering; Sintering (powder metallurgy); Tungsten base alloys
• ISSN: 1555-6255; 0036-0295; 1555-6255; 1531-8648
• DOI: 10.1134/s0036029507060109

A compact material made of a heavy tungsten alloy W-Ni-Fe-Co nanopowder is produced. The nanopowders are synthesized by the treatment of a solid tungstic acid in aqueous solutions of Ni, Fe, and Co salts followed by the reduction of the solid residue by hydrogen at 800°C (the average size of the powder conglomerates is 300 nm, and the conglomerates consist of 100-nm particles). Solid-phase sintering is performed in stages. An increase in the temperature at the last stage from 1300 to 1350 and 1450°C increases the density from 16.7 to 17.2-17.4 g/cm^sup 3^ and the average tungsten grain size to 2.4-4.6 µm. The samples after solid-phase sintering at 1350°C have no porosity. Liquid-phase sintering of nanopowders with high surface and interface energies occurs at 1480°C.[PUBLICATION ABSTRACT]