Transparent Polycrystalline Magnesium Aluminate Spinel Fabricated by Spark Plasma Sintering.

Polycrystalline magnesium aluminate (MgAl O ) spinel (PMAS) exhibits a unique combination of physical, chemical, mechanical, and optical properties, which makes it useful for a wide range of applications, including UV lenses for lithography, electroinsulation, and structural windows for both VIS and IR region radiation and armor applications. Conventional two-stage processing of PMAS involves prolonged pressureless sintering followed by hot isostatic pressing. The costly processing of high-quality transparent PMAS ceramic is the main reason for the limited usage of this material in industry.

On the relation between the microscopic structure and the sound velocity anomaly in elemental melts of groups IV, V, and VI.

The sound velocity of some liquid elements of groups IV, V, and VI, as reported in the literature, displays anomalous features that set them apart from other liquid metals. In an effort to determine a possible common origin of these anomalies, extensive neutron diffraction measurements of liquid Bi and Sb were carried out over a wide temperature range. The structure factors of liquid Sb and Bi were determined as a function of temperature.