The aim of this work was to develop a new joining/repairing material suitable to be easily applied at temperature not exceeding 300°C, in air atmosphere, on large surfaces of SiCf/SiC composites for aerospace applications. The joining/repairing material proposed here is based on a Carbon Fiber‐reinforced commercial Adhesive (CFA) where silicon carbide particles were added. Mechanical strength of the joined SiC/SiC was tested before and after heat treatment at the maximum working temperature for these SiC/SiC. Flexural strengths higher than 200 MPa and 90 MPa, before and after heat treatment, respectively, were obtained by coupling mechanical and adhesive bonding techniques.

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High porous alumina fiber structures appear promising for hot gas filtration in particular for diesel particulate traps. For this purpose, however, a method is required for manufacturing of stable shapes resistant to the blow-out by the gas flow. The sol-gel-process was expected to be the best suited method for fiber bonding to provide the required stability.The main tasks of the development-work were a uniform isotropie fiber-distribution, the adaptation of the sol-gel-process to the application, and the deliberate synthesis of the gel-derived alumina bonding phase.The appropriate fibrous structure was obtained by a repeated filtration of sol/fiber suspensions. The properties of the ceramic binder were adapted by concentrating the sol and/or adding aluminas or aluminium hydroxides.Testing of prototypes with optimized structures has shown, however, that the stability of the structure decreased after thermal load. The thermal fatigue of x-A12O3 is assumed to be responsible for this failure.

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