Effects of Preheating of Powder Before Spark Plasma Sintering of Transparent MgAl2O4 Spinel

The effects of preheating of powder on microstructure and optical transmission for MgAl2O4 spinel ceramics fabricated by spark plasma-sintering processing are investigated. The preheating of powder in air enhances light transmission, whereas it has no remarkable effects on the microstructure. A decrease in light absorption was also observed for the spinel sintered after the preheating, and carbon contamination during sintering was not observed.