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

被引：20

作者：

DeFouw, John D. ^{[1
]}

Quintana, John P. ^{[1
,2
]}

Dunand, David C. ^{[1
]}

机构：

[1] Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA

[2] Argonne Natl Lab, Argonne, IL 60439 USA

来源：

ACTA MATERIALIA | 2008年 / 56卷 / 08期

基金：

美国国家科学基金会;

关键词：

powder processing; chemical synthesis; X-ray diffraction; superconductor; magnesium diboride;

D O I：

10.1016/j.actamat.2007.12.014

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The kinetics of MgB2 synthesis is studied in situ by synchrotron X-ray diffraction, using pressed compacts of 200-400 Pin 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 degrees C. They can be described by diffusion-controlled models of a reacting sphere with kinetics characterized by diffusion coefficients increasing with temperature from 2 x 10(-17) to 3 x 10(-16) m(2) s(-1), with activation energies of 123-143 U mol(-1). Plasma-synthesized boron powders doped with 7.4 at.% carbon show no significant differences in reaction kinetics as compared to undoped powders. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：1680 / 1688

页数：9

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