Mechanochemical processing of sialon compositions
UNSPECIFIED. (2003) Mechanochemical processing of sialon compositions. JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 23 (7). pp. 1069-1082. ISSN 0955-2219Full text not available from this repository.
Milling for 48 h in a sealed planetary ball mill was found to facilitate sialon formation in mixtures of aluminium and silicon oxides and nitrides on further heating in nitrogen at 1200-1600 degreesC. Al-27 and Si-29 MAS NMR indicated that milling exerts more influence on the oxide components than on the nitrides. Substitution of gamma-Al2O3 by AI(OH)3 as the alumina source facilitated the mechanochemical formation of Si-O-Al bonds, as monitored by MAS NMR, but the subsequent thermal conversion of these precursors to stable aluminosilicates did not enhance sialon formation. Milled precursors of beta-sialon composition formed a mixture of beta, O and X-sialon, decomposing to polytypoid sialons at 1600 degreesC. Milled O-sialon precursors formed monophase O-sialon at 1600 degreesC, while some X-sialon compositions formed X-sialon at 1400 degreesC which decomposed to mullite and corundum at 1600 degreesC. A ground mixture of Ca alpha-sialon composition formed beta, O and X-sialons at 1600 degreesC, but no Ca sialon because of the depletion of Ca by the preferential formation of a Ca feldspar. Without milling, all these mixtures were unreactive, and generally did not form sialons on heating in nitrogen up to 1600 degreesC. (C) 2002 Elsevier Science Ltd. All rights reserved.
|Item Type:||Journal Article|
|Subjects:||T Technology > TP Chemical technology|
|Journal or Publication Title:||JOURNAL OF THE EUROPEAN CERAMIC SOCIETY|
|Publisher:||ELSEVIER SCI LTD|
|Number of Pages:||14|
|Page Range:||pp. 1069-1082|
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