The effect of different powder particle size on mechanical properties of sintered alumina, resin- and glass-infused alumina.

Abstract

In this study, the compaction and sintering behavior of fine alumina powders of different particle sizes and the effect of matrix particle size on biaxial strength and fracture toughness of infused matrices were investigated. Three different alumina powders, In-Ceram alumina, A16SG, and RC172 were selected, representing a range of particle size and shape. RC172 and A16SG were dry-pressed. In-Ceram alumina was slip-cast following manufacturer's recommendations. Dry-pressed ceramic blocks were sectioned into disks with a thickness of 1.5-mm. Uninfused disks were sintered at four temperatures between 1250 degrees C and 1400 degrees C. For glass or resin infused specimens, alumina disks were sintered at 1250 degrees C for 2 h and separated into two groups for glass infusion and resin (UDMA/TEGDMA) infusion. Disks were tested for biaxial flexural strength with a universal testing machine (Instron) at 0.5-mm/min crosshead speeds. One-way ANOVA and Duncan's multiple range tests revealed that alumina disks with different smaller particle sizes have significantly higher biaxial strength (p < 0.05). The strength of the alumina matrix was greatly increased by glass and resin infusion. The biaxial strength of resin-infused alumina increased as particle size decreased, whereas strength of glass-infused alumina was constant.