Ceramics-Silikáty 55, (3) 208 - 213 (2011) |
|
COMPOSITES WITH EUTECTIC MICROSTRUCTURE BY HOT PRESSING OF Al₂O₃–Y₂O₃ GLASS MICROSPHERES
|
Prnová Anna 1, Galusek Dušan 1, Hnatko Miroslav 2,
Kozánková Jana 3,
Vávra Ivo 4
|
1 Vitrum Laugaricio – Joint Glass Center of the IIC SAS, TnU AD, FCHTP STU and RONA, a.s.,
Študentská 2, 911 50 Trenčín, Slovak Republic
2 Institute of Inorganic Chemistry, Slovak Academy of Sciences,
Dúbravská cesta 9, 845 36 Bratislava 45, Slovak Republic
3 Department of Ceramics, Glass and Cement, Faculty of Chemical and Food Technology,
Radlinského 9, 812 37 Bratislava 1, Slovak Republic
4 Institute of Electrical Engineering, Slovak Academy of Sciences,
Dúbravská cesta 9, 845 36 Bratislava 45, Slovak Republic
|
Keywords: Al₂O₃–Y₂O₃, Glass microspheres, Hot pressing, Eutectic microstructure
|
In the work we describe the use of Al₂O₃–Y₂O₃ glass microspheres with high alumina contents prepared by flame synthesis as
a precursor for materials with binary eutectic microstructure and high hardness. 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 the mean diameter ≈10 μm were hot-pressed in
vacuum under various conditions (temperatures 840-1600°C, pressure 30 or 40 MPa, isothermal dwell 0-120 min). Hot
pressing at 1600°C without isothermal dwell yielded fully dense bulk materials with fine two phase microstructure with Al₂O₃
and YAG phases percolating at submicrometre level and with hardness 15 GPa. Extension of the isothermal dwell resulted in
undesirable coarsening of the resulting microstructure. |
 PDF (2.5 MB) |
|
