Mechanochemical transformation of α-Fe2O3 to Fe3-xO4-microstructural investigation

被引：35

作者：

Hofmann, M

Campbell, SJ

Kaczmarek, WA

Welzel, S

机构：

[1] Rutherford Appleton Lab, ISIS, Didcot OX11 0QX, Oxon, England

[2] Univ New S Wales, Australian Def Force Acad, Sch Phys, Canberra, ACT 2600, Australia

[3] Australian Natl Univ, Res Sch Phys Sci & Engn, Canberra, ACT 0200, Australia

[4] BENSC, Hahn Meitner Inst, D-14109 Berlin, Germany

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2003年 / 348卷 / 1-2期

关键词：

oxide materials; mechanical alloying; crystal structure; neutron diffraction;

D O I：

10.1016/S0925-8388(02)00808-3

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The effects of wet-milling alpha-Fe2O3 in vacuum for up to 144 h have been investigated by neutron diffraction measurements at room temperature and in situ at similar to950 K. Rietveld refinements show that the main product is iron-deficient magnetite of approximate stoichiometry similar toFe(2.8)O(4). Comparison of the phases derived from the neutron data with results of the Fe2+/Fe3+ oxidation states as determined by chemical analysis reveals that a significant fraction of the unreacted alpha-Fe2O3 occurs in an amorphous-like or disordered state. The wet-milled products are also found to contain similar to8% gamma-Fe2O3. The transformation from the alpha-phase to the gamma-phase occurs as a result of the shearing during the low-energy milling, with the further collisions and impacts leading to defect magnetite on extended milling. While other contributing effects take place, the transformation process from alpha-Fe2O3 to Fe3-xO4 occurs mainly as a result of rupturing the oxide surface layers of alpha-Fe2O3 and releasing oxygen with consequent reduction to Fe3-xO4. (C) 2002 Elsevier Science B.V. All rights reserved.

引用

页码：278 / 284

页数：7

共 31 条

[1]

ANNERSTEN H, 1973, A KRISTALLOGR, V13, P321

[2] Magnetic interactions in hematite small particles obtained by ball milling [J].