Influence of handling and heating cycle on the morphology and flexural strength of glass-infiltrated alumina bars

The main goal of the present study was to evaluate the influence of plaster stability, handling and thermal cycling on the morphology and mechanical strength of glass infiltrated alumina bars. Two different slip casting/thermal processing routes were investigated. The highest flexural strength of alumina bars from In-Ceram® Alumina protocol in comparison to In-Ceram® Sprint protocol was mainly due to its low drying rate and less handling. After glass infiltration and mechanical surface treatments, In-Ceram®Sprint alumina bars presented a non-homogeneous distribution of alumina particles in the glass phase, which was the mais cause for its lower flexural strength. In both cases, it was observed a strong anisotropic growth of alumina particles after glass infiltration. Non-reproducible mechanical surface treatments is other factor that could deteriorate the mechanical strength of alumina bars