Fabrication of transparent MgAl2O4 spinel through homogenous green compaction by microfluidization and slip casting

Abstract In this study, a transparent magnesium aluminate (MgAl 2 O 4 ) spinel prepared by homogeneous green compaction and sinter-HIP processes was investigated. The uniformity of the particle configuration in a green body could be improved by both a wet shaping via slip casting and a microfluidization process, which effectively disintegrates particle agglomerates in aqueous slurry by passing the material through a narrow channel with a high shear stress. The relation between the green body state and the sintering behavior showed that the densification during pre-sintering was accelerated by reducing the mean pore size in the green body, which resulted in a finer microstructure. After post-HIP processing, the final grain size and the in-line transmittance was found to be significantly affected by the pre-sintered state. A high in-line transmittance (ILT=79.3% at λ =550 nm) was achieved in the specimen fabricated via microfluidization and slip casting.