SBIR-STTR Award

In this Phase I, Surmet proposes to demonstrate the feasibility of producing near net shaped conformal window blanks from its spinel material. Surmet has produced ALON domes and windows in a wide variety of sizes and shapes including parts with gentle and complex curvatures, and will apply the same processes to its spinel material. Surmet utilizes a sinter/HIP process to produce its spinel, which results in a material with a dramatically higher strength than hot pressing. Surmet has used this process to deliver over 1,000 spinel lenses to a major defense contractor for their targeting pods. However, inclusions typically found in our spinel material have limited its application. Surmet, in an effort to scale-up the spinel process, have already made process improvements that results in a dramatic reduction in the inclusions in our spinel. These improvements combined with our ALON processing knowledge, will allow Surmet to produce near net shaped, high strength, conformal spinel windows. In Phase II, the process will be scaled up to produce multiple uncracked, fully dense spinel window blanks per program requirements.

Benefit:
The ability to produce near net shaped spinel window blanks will facilitate the development of future conformal sensor systems. Such systems will provide state of the art optical performance while decreasing aerodynamic drag and reducing electromagnetic shielding issues.

Keywords:
EO/IR sensor window, EO/IR sensor window, conformal window, Spinel, Near Net Shape

Surmet will produce prototype, conformal spinel window blanks under the proposed Phase II effort. The particular geometry selection will be made in consultation with a Major Defense contractor who is developing conformal optics for real world applications, and be reviewed with our Navy COTRs. The conformal window will be at least 16 0x9D x 16 0x9D in size and have a sag of at least 6 0x9D . One potential geometry under consideration for the spinel conformal window, is the leading edge of an aircraft wing. During Phase II, Surmet will establish the processes and tooling required to: 1) select and define a particular conformal window shape for the effort, 2) form a spinel green blank, and 3) fully heat treat these conformal spinel green blanks to full optical density. Two full sized conformal window blanks will be produced. Coupons will be cut from large blanks and characterized with respect to, transmission, haze and clarity as well as strength. During the Phase II Option effort, Surmet will inspection polish one of these conformal blanks to a sufficient degree to allow inspection of the material for internal cracks and inclusions, and striae. However, the level of polish achieved will not be sufficient for transmitted wavefront measurements.

Benefit:
Spinel is a material of choice for sensors that require a durable, multispectral window or domes that transmits deep into the Mid-Wave Infrared (MWIR). This program will extend the use of spinel from flat windows and spherical domes to windows with more complex geometries and to domes with hyper-hemispherical geometries.

Keywords:
Multi-spectral windows, Spinel, mid-wave IR, Hyper-hemispherical geometries, conformal window, Domes, Sensors