Optimal sintering parameters for Al ₂ O ₃ optoceramics with high transparency by spark plasma sintering

Transparent Polycrystalline Alumina (PCA) optical ceramics were fabricated at a high heating rate and low temperature by spark plasma sintering (SPS). Maximum pressure (100 MPa) at dwell time keeps the grain size small irrespective of the dwell time. A heating and cooling rate of 100°C min−1 at the sintering temperature of 1150°C for a dwell time of 1 h at 100 MPa yielded highly densified samples with the good transparency of 63 and 83% in visible and infra-red region, respectively. Optoceramics yielded a mechanical hardness of (3000 Hv)/ 29.42 GPa and a thermal conductivity of 21 Wm−1 K−1.