Transparent nanocrystalline spinel by room temperature high-pressure compaction

The present work demonstrates that high pressures alone can initiate and drive densification in nanopowder magnesium aluminate compacts without the application of temperature. The high-pressure processed nanostructured ceramic has a Vickers hardness of 182 and transmits in the infrared and visible wavelengths. The lack of externally applied thermal energy during densification enables the exploration of room temperature diffusion processes confined to nanoparticle surfaces that result in a bulk ceramics with grain sizes equal to the powder particle size.