Low Cost Polycrystalline Alumina for Infrared Windows

Transparent PCA disks were successfully produced by CeraNova using a low cost powder processing method for green body forming, and a combination of sintering and high temperature processing to achieve 100% density and a fine-grained (sub-micron)microstructure. The optical transmittance of the CeraNova PCA compares favorably with competitive fine-grained aluminas, which have been under development for several years. CeraNova's disks (0.8mm and 2.0mm thickness) display low scatter in theinfrared. Transmittance is notably high in the 3.0-4.0 um region of interest for the Navy.Phase II will further develop CeraNova's PCA to improve optical and mechanical properties, including optical transmission, strength and thermal shock resistance. In addition, two different dome shapes as a demonstration of the near-net shape processingwill be produced for further testing. Successful completion of this project will result in the development of a low-cost, near-net-shape process for producing transparent polycrystalline alumina (PCA). The process will be scaleable and will utilize conventional mass production techniques.The resulting PCA material will have high transparency over a broad range of wavelengths and high thermal shock resistance. In addition to military markets for infrared windows, transparent PCA has potential commercial applications in lighting products,watch crystals, and scanner plates. Also, the processing technology proposed could be applied to other ceramic systems to produce high density, high strength, near net shape components with high shape complexity. CeraNova has identified a number ofmarkets and applications where the technology will be more broadly utilized.