ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract By means of EPR, susceptibility, EMP, light-microscopic, thermal and chemical methods the influence of production conditions and subsequent treatments on glassy-phase-containing corundum materials were studied. Melting of the system (Al2O3, SiO2, Na2O, Fe3O4) under reductive conditions leads to a reduction of Fe3+ species contained to Fe2+ and even to Fe0 clusters with ferromagnetic behaviour. Both species markedly influence the mechanical properties of the material by increase of their volumes in consequence of oxidation in subsequent thermal processes. The following model with regard to the localization of the iron species in the system ensues: Fe(III) in corundum, Fe2O3, Fe3O4 and (scarcely) in the glassy phase; Fe(II) in the glassy phase, FeAl2O4 (hercynite) as a solid solution in corundum, and Fe3O4; (Fe0) clusters in corundum. It is therefore not surprising that grinding of the compact material considerably alters the magnetic properties of the samples.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00544212
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