For advanced ceramics composites, affordable manufacturing is still the most essential shortcoming with respect to successful commercial use. This holds particularly for components made out of composites with complex hierarchical structure and high demands of mechanical performance and reliability at the same time, e.g. fibre-reinforced ceramic composites (FRCMCs) which have been developed to overcome the intrinsic brittleness and lack of reliability of monolithic ceramics. Their major advantages include higher temperature capability, lighter weight, better corrosion resistance and adequate damage tolerance. There is a wide spectrum of FRCMCs depending on the chemical composition of the matrix and reinforcement although at present only Cf-C/SiC composites produced by the silicon infiltration route have obtained commercial production level. However, fibre reinforced composites based on oxides (Oxide-Oxide FRCMC) would offer essential advantages with respect to long time stability in oxidizing atmospheres. Although in the past decades there has been a considerable interest in Oxide-Oxide FRCMC, there is at present almost no production concept which meets the requirements in view of cost and performance.  The present work aims at reducing the production costs of FRCMCs by using conventional P/M routes in an approach based on the prepregs technology. FRCMCs will be consolidated by using a porous Reaction Bonded Aluminum Oxide (RBAO) as matrix and commercial alumina fibers as reinforcement. Fig. 1 shows pictures from a feasibility study carried out at TUHH, in which the successful incorporation of commercial alumina fibers in a porous RBAO matrix was proved.

Fig.1: Primary feasibility study showing the problem-free incorporation of commercial alumina fibers (Nextel 610) in a porous RBAO matrix, as well as the enabled toughening mechanisms such as fiber deflection (debonding between the fiber-matrix interface) and fiber pullout. Adapted from: Wendorff, J. Fortschr.-Ber. VDI Reihe 5 Nr. 504, 1997

This project is part of a cooperation between Brazil and Germany called BRAGECRIM (Brazilian German Collaborative Research Initiative in Manufacturing). The Brazilian partner of TUHH in this project is the Federal university of Santa Catarina (UFSC).