Nanocomp Technologies Inc., a Concord, NH-based developer of performance materials and component products from carbon nanotubes (CNTs), has been awarded two new Small Business Innovation Research (SBIR) contracts by the U.S. Air Force.
The first contract is the next step toward commercialization of lightweight CNT wiring as a replacement for copper in air vehicles; the second is a new project, deemed “critical” by the U.S. Department of Defense, to develop CNT material for electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding in aircraft.
The lightweight and conductive nature of CNTs makes them attractive for aerospace applications. Most development activities thus far have occurred on a small scale with ineffective results due to performance, production, and cost limitations; integrating CNT macrostructures into large-scale trials has not yet been achieved.
The first SBIR award builds upon Nanocomp’s successful demonstration, accomplished under a Phase I contract awarded in early 2008, of the use of lightweight conductive wires made from CNTs. During Phase II, Nanocomp will work toward optimizing processing and manufacturing methods to produce CNT wiring in the quantities and forms required for direct integration into aircraft electric power applications.
“As part of Nanocomp Technologies’ Phase I work, we achieved an order of magnitude improvement in our base material’s resistivity. Our yarns, for example, now approach 1x10(-4) ohms/cm,” Peter Antoinette, the company’s President and CEO, told Aerospace Engineering & Manufacturing. “Further, in support of other program activities, we have delivered functional data cables that support transfer rates of more than 300 MB/s.”
In Phase II, “advancing our yarn’s electrical conductivity properties to those of copper for dc power applications is perhaps the most significant technical hurdle to overcome,” Antoinette shared. “That being said, it’s important to realize that CNT electrical behavior does not necessarily mirror that of common metals. The orientation of our individual CNTs from a macrostructure point of view as well as the impact of capacitance effects at higher frequencies all contributes to electrical performance; it’s more than just a numbers game between CNTs and copper (or other traditional metals).”
The performance of CNT wiring is superior to that of copper for high-frequency applications, Antoinette claims, while offering significant weight savings. “By simply replacing the braided shield of commonly used cables (e.g., coax, twisted pair) with Nanocomp’s CNT material, we can save 35-40% of the total weight of a cable harness assembly,” he said, noting that additional savings are possible by replacing the inner conductor(s), which can result in weight reductions of approximately 70% for data cables.
“From an aircraft systems' point of view, this translates to a savings of hundreds to thousands of pounds depending on the platform and application,” he said.
The USAF awarded Nanocomp the second SBIR contract to develop CNT mats as a viable substitute for nickel-based conductors in ESD and EMI shielding applications. The goals of this Phase I research program are to optimize the properties of CNT sheet materials to meet shielding requirements, develop a process to integrate the mats into existing commercial EMI/ESD shielding systems, and develop online production quality-control methods.
“The nature and importance of these projects demonstrate the unique potential of our material as the basis for creating game-changing yet cost-effective replacements for traditional aerospace components,” said Antoinette, adding that the company has established an “in-market” price target for its materials that is comparable to aviation-grade graphite fiber.
“Cost effectiveness will be made possible as our manufacturing capacity reaches scale over the next several years,” he said. “We have identified the necessary steps to ensure that this can realistically take place. Our future plans are based on implementing replicable capabilities that exist today (on an engineering basis) as opposed to the need for developing large-scale invention.”
Optimizing its manufacturing process for wire and cable applications is the “critical next piece” of moving to commercialization, according to Antoinette. Current plans place Nanocomp in a significantly larger production facility within one to two years. “We expect to be operating a fully implemented pilot factory, annually delivering millions of kilometers of yarns and more than 50 acres of sheet materials (or greater than 4 aggregated metric tons) by 2013.”
Though the company does not have any products in full-scale production yet, its materials are actively being evaluated—and qualified, in some cases—for future program insertion.