Melt‐Infiltration Processing and Fracture Toughness of Alumina‐Glass Dental Composites

Alumina‐glass composites were prepared by a melt‐infiltration process that is similar to a fabrication method for dental crowns and bridges. Cylindrical alumina samples with green densities ranging from 62% to 72% of theoretical were formed by slip casting followed by sintering at 1100°C for 2 h. A borosilicate glass was infiltrated at 1200°C, resulting in a composite microstructure consisting of fused alumina particles and glass‐filled pores. Fracture toughness of the composites, measured by a chevron‐notch method with a short rod sample, was ∼3.8 MPa·m^1/2 and was relatively insensitive to the volume fraction of alumina in the range of 0.62 to 0.72.