Synthesis and formation mechanisms of molybdenum silicides by mechanical alloying

B. K. Yen, T. Aizawa, J. Kihara

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Abstract

The synthesis and formation of MoSi2, Mo5Si3, and Mo3Si compounds by the mechanical alloying of Mo-Si powder mixtures has been investigated. Ball-milling experiments were conducted for the composition range of 10-80 at.% Si. The formation of molybdenum silicides, especially MoSi2, during mechanical alloying and the relevant reaction rates markedly depended on the powder composition. The spontaneous formation of αMoSi2 during mechanical alloying at 67 at.% Si (MoSi2 stoichiometry) proceeded by a mechanically-induced self-propagating reaction (MSR), the mechanism of which is analogous to that of the self-propagating high-temperature synthesis (SHS). At the compositions of 54 and 80 at.% Si, however, the formation of MoSi2 proceeded by the gradual formation of both the α and β phases instead of the MSR mode. The formation of Mo5Si3 during mechanical alloying was characterized by a slow reaction rate as the reactants and product coexisted over a long period. The milling of Mo-rich powder mixtures up to 150 h did not lead to the direct formation of Mo3Si. The Mo3Si phase appeared only after brief annealing at temperatures of 800°C and above.

Original languageEnglish
Pages (from-to)8-14
Number of pages7
JournalMaterials Science and Engineering A
Volume220
Issue number1-2
DOIs
Publication statusPublished - 1996 Dec 15

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Keywords

  • Mechanical alloying
  • Molybdenum silicides
  • Self-propagating high-temperature synthesis

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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