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 Cobalt and manganese substituted δ-FeOOH were obtained and used in the preparation of Fe, Co and Mn, Fe mixed oxides. Cobalt is present in the oxyhydroxide with 2.8–3.0, oxidation states. Lattice parameters and oxidation state decrease with cobalt content. Mn-substituted phases contain manganese in oxidation states decreasing from 4.0 to 3.3 as the degree of substitution is higher. These Mn-oxidation states imply cation vacancies which are alternatively ordered in octahedral sites along the [001] direction of the δ-oxyhydroxide structure. The thermal decomposition of the cobalt and Mn-substituted samples at 200 ° C leads to mixed oxides with distorted α-Fe2O3 structure and high manganese and cobalt oxidation states. From 200 to 400 ° C, a reduction process takes place, leading to Mn-substituted sesquioxides, while Co-containing samples decompose into mixtures of spinel and α-Fe2O3-structure phases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00580152
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