In situ X-ray synchrotron diffraction study of MgB2 synthesis from elemental powders

John D. DeFouw, John P. Quintana, David C Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The kinetics of MgB2 synthesis is studied in situ by synchrotron X-ray diffraction, using pressed compacts of 200-400 μm magnesium powders mixed with three types of submicrometer, amorphous, high-purity boron powders. Reaction times for commercially available and plasma-synthesized boron powders decreases from 100 to 2 min as temperature increases from 670 to 900 °C. They can be described by diffusion-controlled models of a reacting sphere with kinetics characterized by diffusion coefficients increasing with temperature from 2 × 10-17 to 3 × 10-16 m2 s-1, with activation energies of 123-143 kJ mol-1. Plasma-synthesized boron powders doped with 7.4 at.% carbon show no significant differences in reaction kinetics as compared to undoped powders.

Original languageEnglish (US)
Pages (from-to)1680-1688
Number of pages9
JournalActa Materialia
Volume56
Issue number8
DOIs
StatePublished - May 1 2008

Keywords

  • Chemical synthesis
  • Magnesium diboride
  • Powder processing
  • Superconductor
  • X-ray diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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