reactive spark plasma sintering of y3al5o12-mgal2o4 composites

In this study, y3al5o12-mgal2o4 (yag-spinel) composites, with different molar ratios (1:1 and 1:3), were in-situ fabricated using reactive spark plasma sintering (rsps) technique. to this end, al2o3, mgo, and y2o3 powders were used as the starting materials. in-situ formation of yag-spinel composites was investigated based on the reaction 3.5 al2o3 + mgo + 1.5 y2o3 → y3al5o12 + mgal2o4. both synthesis and densification processes were accomplished using a single-cycle rsps with one-step heating. the rsps process was performed at a sintering temperature of 1300 °c for 30 min hold time with a maximum uniaxial pressure of 90 mpa under vacuum conditions. the synthesized phases and microstructures were investigated by x-ray diffraction and field emission scanning electron microscopy. the unwanted phases such as yap (yalo3) in a composite microstructure were removed using lif additive. lif was used as a sintering aid in the process of sintering. the in-situ synthesized yag-spinel composites exhibited no internal infrared transmittance over the infrared wavelength ranges of 2.5-25 μm.