Krell, A.A.KrellBaur, G.M.G.M.BaurDähne, C.C.Dähne2022-03-092022-03-092003https://publica.fraunhofer.de/handle/publica/34337610.1117/12.4857702-s2.0-1642556725New 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 cera mics 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 transmissivi ty equals that of sapphire approaching the upper theoretical limit at wavelength s of 2.5-4.5 µm. This opens the way to new 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.entransparente KeramikAl2O3Infrarot-Fenstertransparent ceramicaluminainfrared windowinfrared transmissivitysapphireballistic shieldinggrain sizeresidual porosityIR domewet casting approachsinteringAl2O3666620conference paper