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

John D. DeFouw; John P. Quintana; David C Dunand

doi:10.1016/j.actamat.2007.12.014

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

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

21 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 language	English (US)
Pages (from-to)	1680-1688
Number of pages	9
Journal	Acta Materialia
Volume	56
Issue number	8
DOIs	https://doi.org/10.1016/j.actamat.2007.12.014
State	Published - May 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

Access to Document

10.1016/j.actamat.2007.12.014

Cite this

@article{9828b522f4a74c58af93f2cf180cefe4,

title = "In situ X-ray synchrotron diffraction study of MgB2 synthesis from elemental powders",

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.",

keywords = "Chemical synthesis, Magnesium diboride, Powder processing, Superconductor, X-ray diffraction",

author = "DeFouw, {John D.} and Quintana, {John P.} and Dunand, {David C}",

note = "Funding Information: This work was supported by the US National Science Foundation through Grant No. DMR-0319051. The authors thank Dr. J. Marzik of Specialty Materials, Inc. for providing plasma-synthesized powders, Mr. M. Seniw for assistance in creating Fig. 1 , Mr. B. Myers for SEM imaging, and the staff of the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT located at Sector 5 of the Advanced Photon Source) – in particular Drs. Q. Ma and D. Keane – for help in performing the diffraction experiments. Portions of this work were performed at DND-CAT which is supported by E.I. DuPont de Nemours & Co., The Dow Chemical Company and the State of Illinois. Use of the APS was supported by the US Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. ",

year = "2008",

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journal = "Acta Materialia",

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N2 - 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.

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