Processing of short-fiber CMC by ceramic injection molding

Ceramic injection molding has already found its way to industrial manufacturing. As further improvement oxide fibers can be embedded into the ceramic matrix to increase mechanical properties especially at elevated temperatures. Promising fields of application are, for example, aero engines. In the frame of the study described here a process chain for the ceramic injection molding of Al2O3 short fiber reinforced ceramic matrix composites has been developed. Fiber content varied between 10 to 50 Vol.% fibers whereas for binder a well-examined system from KIT, consisting of PE/paraffin/stearic acid + certain additives, was chosen. As expected the fiber content showed a major effect on the rheological properties of the feedstocks. A further important factor was the fiber orientation which depends strongly on the shear profile occurring during feedstock injection.