SBIR-STTR Award

The technology that has sustained tactical missile radomes and other electromagnetic windows is being outpaced by the increasingly challenging thermal, environmental and structural demands of hypersonic flights. New engineered materials, that exceed state-of-the-art capabilities are required to support the next generation of hypersonic vehicles. Silicon nitride is the next-generation material candidate. However, silicon nitride is a ceramic material. As such, it is a strong yet brittle material that can fail catastrophically. The prevention of catastrophic failure necessarily relies on Ceramic Matrix Composite (CMC) technology, an engineered material consisting of fiber reinforcements embedded within a ceramic matrix, in this instance, silicon nitride fibers. This proposal addresses a void in the market: There are no commercially available silicon nitride fibers, and for good reasons. How does one make fibers with a material that does not melt, does not soften, and does not tolerate the presence of impurities at high temperatures? Free Form Fibers does it with lasers. Our proprietary fiber laser printing technology has been used to produce like materials, such a silicon carbide. Under the proposed project, Free Form Fibers will seek to adapt its fiber laser printing technology to the fabrication of fabrication of silicon nitride fibers. Once this goal is reached, Free Form Fibers will move toward establishing a domestic fiber production capacity. In parallel, Free Form Fibers will seek to establish a prototype production demonstration for silicon nitride CMC components.

Benefit:
As a monolithic material, silicon nitride is already present in a broad range of market segments. In consumer product, silicon nitride is present in ever sharp cutlery. In industrial settings, silicon nitride is used in high efficiency cutting tools. In high-performance internal combustion engines, turbines and gears, silicon nitride is used for bearings, and bushing with superior anti-friction properties. Silicon nitride also has exceptional biocompatibility, hence is used for joint replacements. These markets, and all the niche markets that were not mentioned, can represent as many points of entry into existing markets where the available of silicon nitride fibers would afford a significant boost in performance. In parallel to these existing markets, there are emerging applications, such as high efficiency jet engines, with intense market pain. Here as well, the availability of high and ultra-high temperature capable silicon nitride fibers could represent a significant boost for the industry.

Keywords:
Electromagnetic Windows, Electromagnetic Windows, dielectric constant, Loss tangent, Hypersonics, ceramic matrix composites, radomes, ceramic fibers, Silicon Nitride

The technology that has sustained tactical missile radomes and other electromagnetic windows is being outpaced by the increasingly challenging thermal, environmental and structural demands of hypersonic flights. New engineered materials, that exceed state-of-the-art capabilities are required to support the next generation of hypersonic vehicles. Silicon nitride is the next-generation material candidate. However, silicon nitride is a ceramic material. As such, it is a strong yet brittle material that can fail catastrophically. The prevention of catastrophic failure necessarily relies on Ceramic Matrix Composite (CMC) technology, an engineered material consisting of fiber reinforcements embedded within a ceramic matrix, in this instance, silicon nitride fibers. This proposal addresses a void in the market: There are no commercially available silicon nitride fibers, and for good reasons. How does one make fibers with a material that does not melt, does not soften, and does not tolerate the presence of impurities at high temperatures? Free Form Fibers does it with lasers. Our proprietary fiber laser printing technology has been used to produce like materials, such a silicon carbide. Under the proposed project, Free Form Fibers will seek to adapt its fiber laser printing technology to the fabrication of fabrication of silicon nitride fibers. Once this goal is reached, Free Form Fibers will move toward establishing a domestic fiber production capacity. In parallel, Free Form Fibers will seek to establish a prototype production demonstration for silicon nitride CMC components.

Benefit:
As a monolithic material, silicon nitride is already present in a broad range of market segments. In consumer product, silicon nitride is present in ever sharp cutlery. In industrial settings, silicon nitride is used in high efficiency cutting tools. In high-performance internal combustion engines, turbines and gears, silicon nitride is used for bearings, and bushing with superior anti-friction properties and wear resistance. Silicon nitride also has exceptional biocompatibility, hence is used for joint replacements. These markets, and all the niche markets that were not mentioned, can represent as many points of entry into existing markets where the availability of silicon nitride fibers would afford a significant boost in performance. In parallel to these existing markets, there are emerging applications, such as high efficiency jet engines, with intense market pain. Here as well, the availability of high and ultra-high temperature capable silicon nitride fibers could represent a significant boost for the industry. As of this submission, silicon nitride fiber reinforced ceramic matrix composites are likely to make economic sense only in the most challenging commercial applications where benefits far outweigh the cost. The most likely target markets are jet engines, nuclear, and space. The next generation of hypersonic missiles RF windows represents a narrow point of entry, but when where market pain is intense. It seems poised to spur on production of fibers and ceramic matrix composite. Once the rudiments of a production resource are in place, then other commercial applications will become softer market targets.

Keywords:
dielectric constant, ceramic fibers, Silicon Nitride, Loss tangent, Hypersonics, radomes, ceramic matrix composites, Electromagnetic Windows