Effect of particle size distribution of alumina on strength of glass-infiltrated alumina

Glass-infiltrated alumina composites were prepared by infiltrating glass into a pre-sintered alumina. Three different alumina preforms were obtained from various combinations of fine and coarse alumina particles. After infiltration of glass into the porous alumina preforms, their microstructure and strength were studied. The highest bending strength of 510 MPa was observed when the composite was made by mixing coarse and fine alumina powders at a ratio of 6:4. The infiltrated glass corroded the alumina preform, and the dissolved aluminum ions reprecipitated on the alumina grains during the heat-treatment for infiltration.