| High-performance transparent ceramics are one of the most important optical materials for extreme environments applications, which possess both the excellent thermal mechanical properties (high temperature stability, corrosion resistance, high insulation and high strength) of ceramics and unique optical properties of glass materials. As a typical transparent ceramic material, magnesium-aluminum (Mg-Al) spinel ceramics have the excellent properties of cubic isotropy, low density, high melting point, high hardness, high resistance, low thermal expansion, high thermal shock resistance, corrosion resistance, high strength, high temperature stability and near-ultraviolet to mid-infrared light transmission. Therefore, Mg-Al spinel transparent ceramics could be used as infrared guidance windows, fairings of high Mach aircraft, transparent armor and optoelectronic devices, which are highly favored in the fields of national defense and military, aerospace, laser lighting, medical devices, etc. With a long research history and improvement of Mg-Al spinel powder synthesis and sintering technology, a great breakthrough on strength, purity, density and optical properties of Mg-Al spinel transparent ceramic has been made. However, it’s still a challenge to prepare high-performance Mg-Al spinel transparent ceramics due to the eliminate light scattering sites and complicated process dependent parameters. Therefore, in this review, the synthesis of raw material, sintering/densification techniques and the structure, property evolution of Mg-Al spinel transparent ceramics will be discussed systematically, in order to reveal the raw material-process-structure-property relationship. The key problems and possible solutions for preparing high-performance Mg-Al spinel transparent ceramics are illustrated too. |
