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Preparation of Si–C–N–Fe magnetic ceramics from iron‐containing polysilazane
Author(s) -
Li Yongming,
Zheng Zhimin,
Reng Changyu,
Zhang Zhijie,
Gao Wei,
Yang Shiyan,
Xie Zemin
Publication year - 2003
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.400
Subject(s) - chemistry , ceramic , pyrolysis , magnetization , nitrogen , coercivity , pyrolytic carbon , magnetic susceptibility , argon , analytical chemistry (journal) , inorganic chemistry , chemical engineering , crystallography , organic chemistry , physics , quantum mechanics , magnetic field , engineering , condensed matter physics
A new type of hyperbranched polysilazane containing iron (PSZI) compound was synthesized by the polycondensation of silazane lithium salts with FeCl 3 , and the structure of the PSZIs was investigated by IR, NMR and elemental analyses. The PSZIs were pyrolyzed under nitrogen, argon or NH 3 , and magnetic ceramics could be obtained. The ceramic yields of the PSZIs were higher than those of their corresponding silazanes, and the PSZIs or silazanes with reactive groups containing SiH, CHCH 2 or higher branched structures had higher yields. The magnetism of the ceramics could be controlled by a pyrolytic atmosphere and temperature: the saturation magnetization M s ranged from 20 to 100 emu g −1 and coercivity H c ranged from 463 to 50 Oe. The transformation of the magnetic loop of the PSZIs pyrolyzed at different temperatures under NH 3 was quite different from those under nitrogen. It was shown by X‐ray diffraction measurements that the magnetic crystalline form could exist as Fe 4 N, Fe(0) or Fe 3 N depending on temperature under NH 3 , but under a nitrogen atmosphere Fe(0) was nearly the only magnetic crystalline form from 600 to 1100 °C. By dipping or spin‐coating of the PSZI solution, then through pyrolysis under nitrogen, argon or NH 3 , thin uniform magnetic ceramic films could be fabricated on the substrates. Copyright © 2003 John Wiley & Sons, Ltd.