Formation and alloying of elemental nanostructured β-W powders

N. C. Angastiniotis, B. H. Kear, L. E. McCandlish, Kandalam Ramanujachary, M. Greenblatt

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

We have been investigating the reductive decomposition of spray dried ammonium metatungstate (AMT). Reduction of the pyrolysed powder in flowing hydrogen at T≥625°C creates a high surface area microcrystalline form of α-W, with bcc structure. Reduction at T≤575°C results in the formation of a high surface area nanocrystalline form of β-W, with A15 structure and chemical composition of W3O. The ideal A15 structure of W3O (isostructural with Nb3Sn) is a bcc lattice of oxygen atoms with tungsten atoms arranged in pairs on cube faces. In situ reduction experiments carried out in a controlled atmosphere, high temperature X-ray powder diffractometer have shown that W3O transforms to elemental β-W, in which all or nearly all of the oxygen atoms are absent. Various experiments confirming the existence of metastable elemental β-W are described. Initial experiments on its alloying behavior are also discussed.

Original languageEnglish (US)
Title of host publicationNovel Powder Processing
PublisherPubl by Metal Powder Industries Federation
Pages29-39
Number of pages11
ISBN (Print)1878954261
StatePublished - Dec 1 1992
EventProceedings of the 1992 Powder Metallurgy World Congress. Part 1 (of 9) - San Francisco, CA, USA
Duration: Jun 21 1992Jun 26 1992

Publication series

NameAdvances in Powder Metallurgy
Volume7
ISSN (Print)1042-8860

Other

OtherProceedings of the 1992 Powder Metallurgy World Congress. Part 1 (of 9)
CitySan Francisco, CA, USA
Period6/21/926/26/92

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Metals and Alloys

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