Effect of nanospinel additions on the sintering of magnesia-zirconia ceramic composites.

Nanocrystalline magnesium aluminate (MA) spinel powder produced through a coprecipitation method and calcined at 900°C for 1 h was added to magnesia-zirconia composite in the range of 0-25 mass % and sintered at 1600°C for 2 h. Scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques were used for studying the microstructure and the phase composition of the sintered composites. Bulk density, apparent porosity, volume shrinkage, and Young's modulus of the sintered composites were also investigated. The results revealed that the nanospinel addition up to 20 mass % increases the sintering ability and Young's modulus of the composite bodies. Microstructure showed that the presence of nanospinel and zirconia in the triple point between magnesia grains closed the gaps in the ceramic matrix and enhanced the compactness of the composites.