Effect of the Preparation Method on the Oxidation-Reduction Mechanism and the Cation Distribution of Mn-Zn Ferrites

✍ Scribed by B. Gillot; M. El Guendouzi

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 263 KB
• Volume: 106
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1993.1304

✦ Synopsis

The cation distribution of manganese-zinc ferrite (\mathrm{Mn}{0.50} \mathrm{Zn}{0.15} \mathrm{Fe}{2.05} \mathrm{O}{4}) prepared by a ceramic route and wet method was investigated by derivative thermogravimetry (DTG) and X-ray diffraction analyses. Below about (500^{\circ} \mathrm{C}), these ferrites which are oxidized in cation deficient spinels show an incomplete oxidation of tetrahedral (\mathrm{Mn}^{2+}) ions leading to a cation distribution (\left(\mathrm{Zn}{0.43}^{2 .}{ }^{+} \mathrm{Mn}{0.15}^{2+}{ }^{2} \mathrm{Fe}{0.42}^{3+.4}\right){A}\left(\mathrm{Fe}{1.54}^{3}{ }{4}^{3} \mathrm{Mn}{0.32}^{3+4}\right.) (\square{0.14 ; B} \mathrm{O}{4}^{2-}). With increasing temperature further oxidation of (\mathrm{Mn}^{2+}) ions results in the appearance of a rhombohedral phase (\alpha-\left(\mathrm{Fe}{2-z} \mathrm{Mn}{2}\right) \mathrm{O}{3}) rich in iron accompanied by a spinel phase containing the totality of zinc. 01993 Academic Press, Inc.