Universität zu Köln

Luehrs, Hanna, Fischer, Reinhard X. and Schneider, Hartmut (2012). Boron mullite: Formation and basic characterization. Mater. Res. Bull., 47 (12). S. 4031 - 4043. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 1873-4227

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Abstract

A series of boron doped mullites (B-mullite) was prepared from single-phase gels with initial compositions based on a 1:1 isomorphous substitution of Si by B, starting from a 3:2 mullite composition (Al4.5Si1.5O9.75). A high amount of boron (>10 mol.%) can be incorporated into the crystal structure of mullite where it most likely replaces Si. In situ phase formation of B-mullites was studied with high temperature X-ray diffraction and thermal analysis. A decrease of the formation temperature for B-mullite with increasing boron content was observed. With increasing boron content lattice parameters and c significantly decrease, while no systematic evolution of a is observed. Long annealing at 1400 degrees C results in decomposition of B-mullite to boron free mullite and alpha-alumina. At 800 degrees C B-mullite appears to be stable over a period of at least 12 days. The mean thermal expansion coefficient was reduced by 15% upon incorporation of boron which makes the material technologically interesting. (C) 2012 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Luehrs, Hanna UNSPECIFIED UNSPECIFIED UNSPECIFIED Fischer, Reinhard X. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schneider, Hartmut UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-478100
DOI:	10.1016/j.materresbull.2012.08.064
Journal or Publication Title:	Mater. Res. Bull.
Volume:	47
Number:	12
Page Range:	S. 4031 - 4043
Date:	2012
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	1873-4227
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GRANULITE-FACIES METAPELITES; THERMAL-EXPANSION; NATURAL ANALOG; MOUNT-STAFFORD; HIGH-PRESSURE; GRAIN-GROWTH; ALUMINUM; EVOLUTION Multiple languages Materials Science, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47810