J. European Ceram. Soc.

The purpose of the present study is to fabricate alumina glass composites by melt infiltration with better dimensional control through reducing both the presintering and infiltration temperature. Main efforts were put to develop glasses that are chemically compatible with alumina. After extensive investigations, a glass of 21SiO(2)-24B(2)O(3)-35Al(2)O(3)-15Li(2)O-5CaO wt.% was successfully developed. The glass shows good chemical compatibility with alumina at elevated temperatures and low viscosity above 900 degrees C. Dense alumina glass composites can be fabricated by the melt infiltration process at 950 degrees C, which is 150 degrees C lower than the current state-of-art. Investigations showed improved net-shape capability for the newly developed composites, where the total linear shrinkage for the sintering and infiltration at 950 degrees C is less than 0.1%, as compared with the shrinkage of 0.5% induced by the presintering and infiltration at 1100 degrees C. Preliminary mechanical tests showed that the fracture strength and toughness of the composites are 303 MPa and 3.4 MPa m(1/2), respectively. The lower processing temperature and the better dimensional control are the major advantages for the newly developed alumina glass composites. (c) 2004 Elsevier Ltd. All rights reserved.The purpose of the present study is to fabricate alumina glass composites by melt infiltration with better dimensional control through reducing both the presintering and infiltration temperature. Main efforts were put to develop glasses that are chemically compatible with alumina. After extensive investigations, a glass of 21SiO(2)-24B(2)O(3)-35Al(2)O(3)-15Li(2)O-5CaO wt.% was successfully developed. The glass shows good chemical compatibility with alumina at elevated temperatures and low viscosity above 900 degrees C. Dense alumina glass composites can be fabricated by the melt infiltration process at 950 degrees C, which is 150 degrees C lower than the current state-of-art. Investigations showed improved net-shape capability for the newly developed composites, where the total linear shrinkage for the sintering and infiltration at 950 degrees C is less than 0.1%, as compared with the shrinkage of 0.5% induced by the presintering and infiltration at 1100 degrees C. Preliminary mechanical tests showed that the fracture strength and toughness of the composites are 303 MPa and 3.4 MPa m(1/2), respectively. The lower processing temperature and the better dimensional control are the major advantages for the newly developed alumina glass composites. (c) 2004 Elsevier Ltd. All rights reserved