Effect of Y2O3 doping on the high-temperature properties of magnesia aluminate spinel refractories

A series of low-creep magnesium aluminate spinel refractories doped with 0-3 wt% Y2O3 were prepared by sintering at 1750 degrees C. The physical properties, especially the high-temperature properties of the refractories, were investigated. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were applied to characterize the phases and microstructure of the refractories. The results indicated that yttrium aluminum garnet (YAG) could be in situ formed with the addition of Y2O3 in the spinel refractories. This stabilized the grain boundary of the spinel. The mechanical properties and high-temperature creep resistance of the spinel refractory could significantly be improved by the addition of Y2O3.