Cost-Effective Fabrication of Transparent Spinel Domes

Sapphire is the state of the art material for windows and domes with requirements for transparency from the visible to the mid-wavelength infrared (MWIR) region, where environmental loading is an issue. Unfortunately, sapphire is expensive and costly to fabricate due to its an-isotropic properties. Spinel combines superior MWIR transparency with isotropic properties. Consequently, it can be formed into near net shapes, and fabricated at lower costs than sapphire. The combination of improved transparency with potential for lower cost, make spinel an attractive candidate for high volume applications such as the Common Mode Missile. However, there has never been a reliable supply of optical Spinel material. One reason for this is the lack of reliable supply of Spinel powder. In Phase I Surmet will modify commercially available powder as well as synthesize its own powder. This powder will then be consolidated and heat treated to full density. Surmet's spinel process will combine the best practices of its production ALON process with lessons learned during their ongoing spinel development effort with a customer. At the end of the Phase I program, optically transparent 6" hemispherical spinel domes will be delivered to the Army for further testing and performance evaluation, to be followed by program review and Phase II consideration.