Transparent MgAl2O4 ceramic produced by spark plasma sintering

A two-step pressure profile was used to prepare transparent MgAl2O4 ceramic without sintering aids by spark plasma sintering (SPS) at 1300 °C for 3 min. The influence of the pressure profile was investigated systematically and the discoloration in the present study was attributed to the dislocation formed during the fast densification in SPS. At low pre-load pressure, 5 MPa, with the normal characteristic fast heating rate (100 °C min−1), high inline transmittance of 51% at 550 nm and 85% at 2000 nm can be achieved.