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.