SBIR Phase I: Lower Cost Carbon-Carbon Composites Densified by Microwave Heating

This Small Business Innovation Research Phase I project addresses the need for more cost effective, carbon/carbon (C/C) composites with improved properties. Microwave processing will be investigated to enhance densification of C/C composites traditionally produced by lengthy chemical vapor infiltration (CVI) processes that are known to be very costly. The innovation is to utilize microwave processing to produce temperature gradients within individual components, such that it will be possible to preferentially densify from the inside-out thus reducing densification times and potentially improving material properties. Materials Focus has developed technology that enables microwave heating of electrically conductive carbon fiber performs at low pressures in hydrocarbon environments without arcing that results in sooting and preferential heating at the soot deposits. This program will continue this research to achieve the best microwave equipment design/setup and to optimize processing parameters to demonstrate significantly shorter CVI times. Composites will be densified and characterized to assess progression of densification, measure strength, and provide an evaluation of the cost benefits over traditional CVI processing techniques. It is anticipated that densification times will be significantly reduced without detrimentally affecting the properties of the C/C composites. High specific strength C/C composites have been used for decades in high technology applications. The development of lower cost, higher strength C/C composites would be enabling to a multitude of industries requiring high performance friction components as well as aerospace and defense applications necessary for national defense. This includes aircraft brakes, clutch plates, rocket nozzles, and gas turbine engine components. As the cost of carbon and graphite fibers is escalating, lower cost processing techniques are required to make these materials more cost effective. The microwave CVI process is better than conventional CVI since it has potential to significantly reduce processing times which could result in substantial manufacturing processing cost reductions and improved composite properties. An additional benefit of microwave processing to society is that it is environmentally friendly and typically results in energy savings. The scientific value will arise from improved understanding of the interaction of microwaves with different materials and how microwave equipment design is critical for the heating of high electrical conductivity materials. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).