Amorphous networks, consisting of the elements Si, B, N and C are surprisingly highly durable: in an inert atmosphere, the onset of weight loss starts between 1800 and 2000 °C, depending on the molecular precursor employed. Unparalleled among nitride materials are the resistivity against oxidation and crystallization. Particularly promising is the application of these novel materials as ceramic fibers in ceramic fiber reinforced ceramics (CFCs) for the aerospace industry.
In a novel synthesis strategy, three-dimensional covalently bonded nitride and/or carbide networks are built up in a ternary or quaternary system. The high degree of cross-linking in such random networks, which is due to the presence of nitrogen and carbon in the network, may lessen the crack propagation inside a workpiece. Moreover, the material properties may be optimized by varying the elemental composition.
Applications of Si/B/N/(C) ceramics
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