Luminescent Eu3+-doped transparent alumina ceramics with high hardness

The Eu3+-doped transparent aluminas were prepared by wet shaping technique followed by pressure-less sintering and hot isostatic pressing. The effect of dopant amount on microstructure, real in-line transmission (RIT), photoluminescence (PL) properties, hardness and fracture behaviour was studied. The RIT decreased with increasing amount of the dopant. The PL emission spectra of Al2O3:Eu3+ ceramics exhibited predominant red light emission with the highest intensity (under 394 nm excitation) for material containing 0.125 at.% of Eu3+ and colour coordinates (0.645, 0.355) comparable with commercial red phosphors. The doping resulted in hardness increase from 26.1 GPa for undoped alumina to 27.6 GPa for Eu-doped sample. The study of fracture surfaces showed predominantly intergranular crack propagation micro-mechanism.