Reactive sintering of YAG-based materials using micrometer-sized powders

This study reports the understanding of the main features affecting the microstructure and optical properties of polycrystalline yttrium aluminum garnet (YAG) obtained by reactive sintering of commercial micrometer-sized powders. Two shaping techniques, cold isostatic pressing and slip casting, are studied and the properties of samples at the green stage related to the behaviour during vacuum sintering, to the final microstructure and the transparency. The most promising results in terms of transparency and final density were obtained by cold isostatic pressing, whereas high green densities were obtained by slip casting, but a non-homogeneous particle packing inhibits the pore closure during sintering, thus limiting the final density and the transparency.