Pulsed electric current sintering of transparent Cr-doped Al2O3

Pulsed electric current sintering (PECS) was applied to obtain transparent ruby polycrystals. Al2O3-Cr2O3 powder mixture was prepared by drying an aqueous slurry consisting of Al2O3 and Cr(NO3)3 followed by PECS consolidation in vacuum at a sintering temperatures ranging from 1100 to 1300 °C with various heating rates between 2 and 100 °C/min and under an applied pressures from 40 to 100 MPa. Slow heating rate and high-pressure lead to highly densified and transparent Cr-doped Al2O3 polycrystals at sintering temperature of 1200 °C.