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Journal of Materials Science

, Volume 32, Issue 18, pp 4957–4965 | Cite as

Synthesis and growth mechanism of ThO2–W–Mo alloy nanocomposite powder

  • X Devaux
  • A Thomy
  • J Ghanbaja
Article

Abstract

Nanocomposite ultrafine powders of thorium oxide and tungsten molybdenum alloy were prepared by arcing between a pure molybdenum cathode and a thoriated tungsten anode under an argon–hydrogen atmosphere. The microstructure, morphology and chemical analyses of the ultrafine powders were examined by X-ray diffraction, transmission electron microscopy and associated techniques. The powders are composed of thorium oxide single-crystalline nano-grains decorated by tungsten molybdenum alloy particles which are crystallized in a metastable A15 structure. Two morphologies were observed: octahedra and needle-like particles. Every octahedral particle bigger than 15 nm had on each corner a metallic grain generally less than 8 nm in size. The needles had a length below 600 nm and their width to length ratio ranged from 1/3–1/15. They all presented on one of their ends a metallic particle which was comparable in size to the needle width. Other smaller particles (<10 nm) may be encountered along the edges. The metallic particles were found to be epitaxial on the thorium oxide grains according to the relation: (100) [011]ThO2∥(100) [011]A15. The extensive study of the microstructural and morphological properties of the powders leads us to suggest a growth mechanism of the nanocomposite particles.

Keywords

Heterogeneous Nucleation Metallic Particle Collodion Nanocomposite Particle Nanocomposite Powder 

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Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • X Devaux
    • 1
  • A Thomy
    • 2
  • J Ghanbaja
  1. 1.Laboratoire de Metallurgie Physique & Science des MateriauxNancy CedexFrance
  2. 2.Service Commun de Microscopie ElectroniqueUniversite Henry PoincareVandoeuvre les NancyFrance

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