Spark plasma sintering (SPS) of transparent magnesium-aluminate spinel

The spark plasma sintering of commercial magnesium aluminate powder, the effect of LiF additions to it, and the resulting optical properties of the transparent solid, was analyzed. Two sets of samples of magnesium aluminate were taken, one without any addition and the other with the LiF insertion. The samples were treated with SPS apparatus and their density was determined by the liquid displacement method. The X-ray diffraction projected the presence of the spinel diffraction peak and the metallographic and scanning electron microscopy clearly revealed the difference in the microstructure of the undoped and the LiF-doped spinel. The SPS consolidation treatment helps in attaining full densification of the spinel powder. The results show that the presence of LiF dopant has a bearing on the spinel morphology, which helps in producing large well-defined grains, eliminates residual boundary phases, and allows attaining high levels of light transmission.