Production of refractory-metal ultrafine particles by gas evaporation method and their surface oxide layer

Yuki Kimura, Chihiro Kaito

Research output: Contribution to journalArticlepeer-review

Abstract

Generally, molybdenum, tungsten or tantalum is used as the evaporation source of many kinds of materials because of their high melting points and reasonably low vapor pressures. Therefore, the production of ultrafine particles of molybdenum, tungsten and tantalum has not been achieved by gas evaporation method. In this paper, it is shown that ultrafine particles of molybdenum, tungsten and tantalum were produced by a modified gas evaporation method. Transmission electron microscope observations show that the produced particles had a bcc structure with a size of less than 50 nm. Then, the thicknesses and the structures of the natural oxide layers were determined. Metallic particles develop an oxide layer on their surface and produce composite material automatically. Therefore, when metallic particles are used industrially or are treated in theoretical calculation studies, in view of realistic materials, the effect of the natural oxide layer must be considered. By the use of this modified gas evaporation method, ultrafine particles of many kinds of refractory materials will be produced.

Original languageEnglish
Pages (from-to)4159-4162
Number of pages4
JournalSurface and Coatings Technology
Volume202
Issue number17
DOIs
Publication statusPublished - 2008 May 25

Keywords

  • 61.46.Df
  • 68.37.Lp
  • 81.16.Pr
  • 81.65.Mq
  • Molybdenum
  • Nanostructure
  • Oxide
  • Tantalum
  • Transmission electron microscopy (TEM)
  • Tungsten

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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