A transmission electron microscope study of hydrothermally synthesized yttrium disilicate powders

MacLaren, I. , Trusty, P.A. and Ponton, C.B. (1999) A transmission electron microscope study of hydrothermally synthesized yttrium disilicate powders. Acta Materialia, 47(3), pp. 779-791. (doi:10.1016/S1359-6454(98)00405-4)

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Abstract

The crystallization of three hydrothermally synthesized Y2Si2O7 precursor powders at temperatures between 991 and 1038°C has been studied using transmission electron microscopy. Powders prepared in acidic or near-neutral conditions were found to be highly inhomogeneous both chemically and microstructurally, with a wide range of crystalline phases formed. In contrast to this, a powder prepared in alkaline conditions was found to be very homogeneous. Small crystalline nuclei were formed in this powder on heating to 1006°C which grew rapidly at 1038°C to form large single crystal particles. The majority of these had the α-Y2Si2O7 phase but some were of the y-Y2Si2O7 phase. The reasons for the formation of this y-phase are unclear, although it would be expected to transform to α-Y2Si2O7 on further heat treatment at 1200°C. Weaknesses in the current crystal structure data for yttrium disilicate phases are identified and suggestions made for rectifying them.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:MacLaren, Dr Ian
Authors: MacLaren, I., Trusty, P.A., and Ponton, C.B.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Acta Materialia
Publisher:Pergamon
ISSN:1359-6454
ISSN (Online):1873-2453
Published Online:13 September 1999

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