Dr. Barak Ratzker**
Auditorium, Meidan, for green pass holders, or via ZOOM
Transparent oxide ceramics have many advantageous traits making them viable for a wide range of applications, from transparent armor to photonic materials. Spark plasma sintering (SPS) is a pressure-assisted sintering technique that can be employed for the fabrication of such materials. An advanced approach, termed high-pressure SPS (HPSPS), involves using special hybrid tooling which allows increasing the applied pressure by an order of magnitude (up to ~1 GPa). Consequently, HPSPS allows reducing sintering temperature, minimizing grain growth, and preventing carbon contamination. As a result, it is possible to fabricate transparent and nanostructured ceramics with unique mechanical and optical properties. In this talk, I will present and discuss several key aspects of HPSPS regarding transparent oxide ceramics: First, understanding the effect of pressure on microstructure evolution of transparent alumina during HPSPS, including phenomena of stress-enhanced grain growth and development of non-uniform microstructure. Next, a microstructural study of deformation in nanocrystalline MgAl2O4 spinel fabricated by HPSPS, including the inverse Hall-Petch phenomenon. Finally, examples of transparent laser ceramics (e.g. Cr3+:Al2O3, Co2+:MgAl2O4) were achieved by HPSPS and their optical properties. Ultimately, HPSPS can enable the development of new transparent ceramic materials for advanced applications.
*Post-doctoral fellow at Dr. Maxim Sokol Group