UNSPECIFIED. (2003) Mechanochemical processing of sialon compositions. JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 23 (7). pp. 1069-1082. ISSN 0955-2219

Abstract

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.

Data sourced from Thomson Reuters' Web of Knowledge

Request changes to a record

Actions (login required)

View Item