Technology Applications
Success Stories: Silicon Carbide Mirrors Offer Beryllium Alternatives
| Company | Trex Enterprises Corporation (San Diego, CA) |
| Technology | Silicon Carbide (SiC) Mirrors |
| Description | Trex is developing a chemical vapor composite process to produce SiC precision optics. During the process, particulate materials, either whiskers or powders, are added to relieve the strain in the build-up as it grows. This step gives the part better mechanical and isothermal properties. In addition, the process can be accomplished at a faster rate, which improves affordability. The end product is a fully dense part, which becomes a mirror blank, which is then polished. Critical issues being addressed include "polishability" and "scalability."
Working with QED, Inc., Trex has made significant improvements in surface figure and roughness without the need for adding a layer of silicon on top of the mirror to facilitate polishing. Trex is also working to scale-up the process to produce optics with diameters of up to 1 meter (reactor size 1.5 meter). |
| MDA Use | SiC mirrors have many applications in the Ballistic Missile Defense System. Perhaps the nearest-term use is for the Exoatmospheric Kill Vehicle (EKV). The EKV telescope uses beryllium mirrors, which could be replaced with SiC mirrors. Beryllium presents many manufacturing, toxicity, and program risks and the MDA's interest is in phasing out this material. Additional beryllium replacement opportunities exist for mirror backings and other support structures. Future kill vehicles, as the Airborne Laser programs, could benefit from SiC mirrors. |
| Insertion Opportunity | With the support of the Ground-based Midcourse program and the Producibility and Mantech Directorate, Trex is working with Raytheon to test the technology for use in the EKV and future kill vehicles. The company is already selling the mirror technology in commercial and military markets. Mirror products are being produced with diameters of up to 0.4 meters. |