Development of Transparent MgAl₂O₄ Spinel Ceramics

Abstract

The present paper summarizes the technology and basic process for fabricating transparent ceramic MgAl2O4 spinel and introduces a scalable production technique. Fully transparent polycrystalline spinel has been prepared by combined vacuum sintering, hot-pressing, sintering in H2 atmosphere and hot isostatic pressing(HIP). The optical transmittance of the specimen sintered at 1500°C following HIP at 1800°C was nearly the same as that of single crystal spinel. When radiated by γ-ray and X- ray, colorless spinel became brown due to V-type color centers, which decreased its transmittance. On the other hand, the spinel ceramics’ resistance to radiation improved by doping CeO2.

Molten Salt Synthesis and Formation Mechanism of Plate-Like MgAl₂O₄ Spinel

“…Magnesium aluminum (MA) spinel has received a great deal of attention from academia and the industry sector because of its many excellent properties, such as high melting point, high thermal shock resistance, excellent slag corrosion resistance, small density, high temperature resistance and oxidation resistance [1][2]. As one of the important raw materials, MA spinel was widely used in different fields, such as refractory materials, laser materials, electronic materials and ceramics [3][4]. For example, MgAl 2 O 4 transparent ceramics can be widely used in the manufacture of missile hoods, transparent armor, the insulated framework of electronic components, infrared band window materials, as well as the light-emitting substrate of projection television [5][6][7][8].…”