FIBRE-REINFORCED COMPOSITE CERAMICS AND METHOD OF PRODUCING THE SAME

摘要

The invention concerns fibre-reinforced composite ceramics with hightemperature fibres, in particular based on Si/C/B/N, which are bound in terms of reaction to an Si-based matrix. These composite ceramics are produced by impregnating bundles of fibrous material comprising Si/C/B/N fibres with a binder which is suitable for pyrolysis and solidifying the binder, the fibrous material bundles then optionally being conditioned with a silicating protective layer suitable for pyrolysis, such as for example phenolic resin or polycarbosilane. Subsequently a mixture of fibrous material bundles, fillers, such as for example SiC and carbon in the form of graphite or carbon black, and binders is produced. The mixture is then compacted to form a green compact which is then pyrolysed under vacuum or protective gas in order to produce a porous shaped body which is then infiltrated, preferably under vacuum, with molten silicon. In this way, fibre-reinforced composite ceramics which have greatly improved properties with respect to conventional composite ceramics and are in particular suitable for use in heavy-duty braking systems can be produced in an efficient manner suitable for production on an industrial scale.