COMPOSITES WITH EUTECTIC MICROSTRUCTURE BY HOT PRESSING OF Al2O3-Y2O3 GLASS MICROSPHERES

The use of Al2O3-Y2O3 glass microspheres with high alumina contents prepared by flame synthesis as a precursor for materials with a binary eutectic microstructure and high hardness was studied. XRD amorphous microspheres with eutectic composition in a pseudobinary system Al2O3-Y3Al5O12 (YAG) were pr...

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Bibliographic Details
Published in:Ceramics (Praha) 2011-01, Vol.55 (3), p.208-213
Main Authors: Prnova, A, Galusek, D, Hnatko, M, Kozankova, J, Vavra, I
Format: Article
Language:English
Subjects:
Al2O3–Y2O3 glass microspheres
Dwell
Eutectic composition
Eutectic microstructure
Eutectics
Glass
Hardness
Hot pressing
Microspheres
Microstructure
Precursors
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Summary:The use of Al2O3-Y2O3 glass microspheres with high alumina contents prepared by flame synthesis as a precursor for materials with a binary eutectic microstructure and high hardness was studied. XRD amorphous microspheres with eutectic composition in a pseudobinary system Al2O3-Y3Al5O12 (YAG) were prepared by feeding a crystalline powder precursor of respective composition into methane-oxygen flame. The microspheres with a mean diameter of about 10 micron were hot-pressed in vacuum under various conditions (840-1600 C; 30 or 40 MPa; isothermal dwell 0-120 min). Hot pressing at 1600 C without isothermal dwell yielded fully dense bulk materials with a fine two phase microstructure with Al2O3 and YAG phases percolating at the submicron level and with a hardness of 15 GPa. Extension of the isothermal dwell resulted in undesirable coarsening of the resulting microstructure.
ISSN:0862-5468
1804-5847