sintering behavior and microstructural evaluation of MgO-doped α-Al₂O₃

There have been widespread interests in recent decades in porous ceramics owing to their specific properties, such as low bulk density, low specific heat, low thermal conductivity and high specific surface area. Alumina has been one of the first developed advanced ceramics to be used in load bearing applications as orthopedic implants. The properties of α-Al₂O₃ can be modified by introducing a second suitable metal oxide to form a composite oxide. Among various metal oxides MgO is considered as a promising metal oxide which can modify the properties of alumina in the α-Al₂O₃ -MgO mixed oxides by grain growth inhibition due to the strong basic characteristics of MgO. In this work, porous α-Al₂O₃ – MgO alumina-based ceramics were fabricated by a tape casting method and powder metallurgy technique. MgO-doped α-Al₂O₃ ceramics sintered at 1400°C for 2-4-6 h in air atmosphere. The effect of sintering time on the porosity, density and shrinkage properties of samples were investigated. The sintering behavior, surface morphology, elemental distribution and phase evaluation of the composite ceramics were evaluated by SEM-EDX and XRD, respectively.