Transparent sintered sub-µm Al2O3 with IR transmissivity equal to sapphire

Andreas Krell; Guenter M. Baur; Claus Dahne

doi:10.1117/12.485770

26 September 2003 Transparent sintered sub-μm Al₂O₃ with infrared transmissivity equal to sapphire

Andreas Krell, Guenter M. Baur, Claus Dahne

Proceedings Volume 5078, Window and Dome Technologies VIII; (2003) https://doi.org/10.1117/12.485770
Event: AeroSense 2003, 2003, Orlando, Florida, United States

Abstract

New grades of sintered (polycrystalline) corundum ceramics have been shown to exhibit a ballistic shielding power close to SiC/B4C composites when manufactured with a grain size of about 500 nm. It is demonstrated here that these Al₂O₃ ceramics become transparent when their residual porosity is decreased to less than 0.05 %. Specifically, in the IR range between about 2 and 6 μm their transmissivity equals that of sapphire approaching the upper theoretical limit for wavelengths of 2.5-4.5 μm. This opens the way to new possible applications such as IR domes. These optically and mechanically homogeneous ceramics can be manufactured with a wall thickness up to 15 mm by a wet casting approach. The technology enables the manufacture of complex hollow spheres which after sintering are transparent in visible light without polishing.

Citation Download Citation

Andreas Krell, Guenter M. Baur, and Claus Dahne "Transparent sintered sub-μm Al₂O₃ with infrared transmissivity equal to sapphire", Proc. SPIE 5078, Window and Dome Technologies VIII, (26 September 2003); https://doi.org/10.1117/12.485770

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