Advanced Window Materials for High Energy Propulsion

Window materials are an essential component of some advanced propulsion concepts which require high pressures, high temperatures, low energy losses, and low weights. Window materials must possess a combination of properties such as high mechanical strength, high melting point, high transparency, low density, and good resistance to the operating environment. CeraNova proposes the development of fine-grain, polycrystalline alumina as an advanced window material for this application. While it possesses the same intrinsic properties as sapphire, nanograin polycrystalline alumina developed by CeraNova for IR domes and windows also demonstrates enhanced extrinsic properties including hardness, strength, erosion resistance, and thermal shock resistance, due to the fine grain, isotropic polycrystalline microstructure. With appropriate microstructural and chemical control, as proposed here, high transmittance in the UV and visible are also possible. CeraNova proposes teaming with the Advanced Ceramics at the University of Dayton Research Institute due to their strong background in and test facilities for optical materials, and their interactions with personnel and projects in optical materials at WPAFB. Through technology transfer collaboration with UDRI, CeraNova will gain enhanced understanding of the design, testing, evaluation, and performance of optical materials, windows, and advanced propulsion systems to tailor polycrystalline alumina for this application.