Starfire Systems, a developer and supplier of silicon carbide (SiC) pre-ceramic polymer technology, and Goodrich Corporation, a recognized leader in the development and manufacture of friction materials and ceramic composites, will leverage the results of recent ceramic matrix composite (CMC) friction material development programs to support the development of a low cost SiC based CMC friction material for the JSF lift fan clutch plate. The program goal is to develop an SiC clutch plate capable of 4500 engagements (3X improvement) in the JSF lift fan application. The team will leverage experience from aircraft (CCAB) and auto racing programs (Formula 1) to select a minimum of three candidate SiC CMC friction couples for feasibility testing on a screening dynamometer for direct comparison to a carbon-carbon baseline. A base set of CMC friction formulas including modified carbon-carbon, fabric and felt preforms will be evaluated. The SiC matrix will be tailored to achieve maximum durability through variations in processing conditions and the addition of stabilizing elements such as zirconium. To support broader commercialization by accelerating the prototyping process, the team will review historical CMC friction data to create a methodology for rapidly selecting friction material formulas for any generic friction application.
Benefit Starfires ceramic-forming polymers can be combined with powders, whiskers, fibers, and substrates to form toughened ceramic materials that are erosion resistant and capable of handling both extreme temperatures and severe thermal shock loadings. These SiC based materials have the physical properties that can extend the lifetime of the clutch plate and are made by a manufacturing processing that is easily scalable and cost-effective. These factors will greatly reduce the cost of ownership of the clutch plate (the aircraft system), while improving the performance of the lift fan subsystem. The efforts performed under the Phase 1 SBIR and, potentially, under Phase 2 are complementary to current in-house research and production activities. Starfire is in the business of developing and producing low cost pre-ceramic polymer based materials optimized for customer-driven applications. Starfire continues to support development opportunities with the primary focus of supplying the raw materials to component manufacturers. As a material supplier, Starfire is highly motivated to enable traditional component suppliers, like Goodrich, to produce upgraded or new components using the advanced materials developed by Starfire Systems. The primary benefits will be derived from a longer lived, lower cost clutch plate for the JSF STOVL variant that will significantly reduce maintenance down time and related logistics cost by tripling the life of the clutch plate and by reducing the clutch materials sensitivity to both battle damage and environmental exposure (fluids). These same technology developments may also yield near term benefits related to advanced aircraft braking systems. By developing a more thorough understanding of how ceramic friction materials perform in different environments, the materials and friction systems developers will be able to tailor the ceramic materials for optimum life and friction performance in a broader range of friction applications. Just as the auto industry has relied on the modification of friction material formulations to meet the ever-increasing requirements of consumer automobiles, CMC friction materials can be modified, doped with metals or ceramics, crystallized, or designed to glaze at a specific temperature to meet the requirements of a broad range of applications. The carbon-carbon industry has very little flexibility in the formulation of carbon brakes. But, by combining the pre-ceramic polymers with carbon, the options for system tailorability and design flexibility expand significantly. With this increased design flexibility, lower cost, higher performance friction materials can be developed for both military and commercial aircraft, such that the overall cost of operation can be significantly reduced. The benefits to the commercial airline industry could be significant, considering that the cost of aircraft wheels and brakes represent the third largest operational cost item behind fuel and labor. The cost and performance benefits will accelerate the adoption of engineered ceramic materials into multiple aerospace applications. The results of this SBIR project (Phase I and Phase II) will provide a basic roadmap of friction performance versus CMC formulation that will enable Starfire Systems and friction material manufacturers like Goodrich to reduce the development cycle time and rapidly formulate ceramic friction materials for new applications without the extensive trial and error research that currently is applied in each new friction application. A significant number of ceramic friction demonstrations have been performed by a diverse set of participants, and the task of categorizing the material performance versus the material tested can be used to accelerate introduction of CMC friction materials into new applications. The screening tests of friction and wear for the candidate systems will also provide a basic understanding of the variability of the performance that can be obtained through basic tailoring of the raw materials and processing conditions. From this screening sample a basic material versus application guide can be established to provide designers with first cut CMC material choices when designing a new system requiring friction materials. A secondary commercial benefit, that is often overlooked, is the adoption/certification of a new material into a military system. This qualification acts as a sign post to industry that the selected material technology is mature, robust, and proven. The value of this certification opens the doors to commercial applications like automotive brakes and clutches. The recognition that a material system has achieved this level of acceptance also reduces the cost of capital for expansion of production facilities to supply both commercial and military applications. As a raw material supplier, Starfire also benefits from this level of validation because it encourages other manufacturers to begin working with the new material systems, which not only broadens the number of applications but also lowers the overall cost to all customers. Keywords silicon carbide, starfire matrix polymer, polymer derived ceramic, ceramic friction material, ceramic matrix composites, ceramic brakes
