The effect of pre-annealing and post-annealing on the transparency of MgAl2O4, prepared by slip casting and spark plasma sintering (SPS)

The aim of this paper is to investigate the effect of slip casting process and the annealing before and after sintering to achieve a transparent MgAl2O4. To remove contaminants such as carbon from the structure of shaped spinet bodies, at first, the samples were annealed at temperature of 800 degrees C, 900 degrees C and 1000 degrees C for 2 h and then sintered at 1400 degrees C. By annealing the sample before sintering at 900 degrees C, the transmission increased (15% at IR region and 10% at visible region). Although by annealing the samples, the amount of carbon contamination reduced. Annealing the samples after sintering also had some desirable results. The samples annealed at temperature of 1200 degrees C for a time of 3, 5 and 10 h. The darkness of samples reduced due to the removal of carbon impurities and the sample was annealed at 1200 degrees C for 5 h had the most transparency in the visible and infrared regions.