Phase I aims to demonstrate the feasibility of fabricating preforms for ceramic composite shapes of interest to fossil energy by using proprietary three-dimensional braiding technology. High performance ceramic composites, operating in extreme conditions of temperature and corrosive environment, require preform architectures that can provide toughness, strength, and a capacity to eliminate failure from incipient crack formation in the ceramic matrix. This requires a three-dimensional fiber architecture, providing strength and stiffness in all directions and an intertwined network of fibers capable of confronting and deflecting any cracks that may form in the host matrix during operation. This crack containment results in damage containment and continued operation of the ceramic composite component. Lifetime and reliability should be greatly extended. Three dimensional braids operate successfully in polymeric composites. They provide reinforcement and enhance mechanical properties in three dimensions, extend life-time and reliability, and provide damage tolerance of a high degree. Although the failure mechanisms appear different for ceramic composites, the existence of these braided preforms is expected to have comparable effects on ceramic composites. Phase I selects refractory fibers and will attempt to make preforms from them, using three-dimensional braiding technology, in shapes of interest to fossil energy. Various fiber architectures will be made to determine the flexibility of the refractory fibers to operate in the range of fabrication capability of the braiding technology.Anticipated Results/Potential Commercial Applications as described by the awardee:Successful preforms must be incorporated into ceramic matrices. A successful ceramic composite formation will offer the capability to make high performance parts that can operate successfully, and for long times, in extreme thermal and corrosive environments. The commercial implications are profound. The temperatures for operation are increased, increasing efficiency and reducing operating costs. Ceramic composites using three-dimensional braided preforms will permit advances in fossil energy technology and also find broad application in such industries as gas turbine engines, nuclear power, missiles, chemical processing, and metallurgical processing.
