Polycrystalline alumina (PCA) has great potential for providing performance comparable to or better than single-crystal sapphire, yet offers the opportunity for low-cost powder based manufacturing. CeraNova has demonstrated transparent PCA, by processing the material to simultaneously achieve 100% density and sub-micron grain size. CeraNova PCA displays low scatter in the infrared, with high transmittance (>85%) in the 3.0-4.0μm region, comparable to sapphire. In addition, the sub-micron grain size leads to high hardness, high strength and high thermal shock resistance. This fine-grain PCA is a viable sapphire replacement for dome applications, including those that require aerodynamic shapes readily possible by powder processing. Such shapes present not only processing challenges, but also surface finishing issues. Results from a current program to address these issues in creating an ogive dome of PCA are discussed.
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