Advances in inorganic fibers

Many types of ceramic fibers have been developed over the last 60 years. Of these, carbon fiber has grown into a large market involving fiber-reinforced plastics and lightweight heat-resistant composites. In addition, many modifications of SiC-based fibers have been achieved. SiC-polycrystalline fibers (Hi-Nicalon Type S and SA fiber) with excellent heat-resistance have been developed and their many applications have been examined. A tough, thermally conductive SiC-based ceramic (SA-Tyrannohex) composed of a highly ordered, close-packed structure of hexagonal columnar fibers has also been produced. Recently, using a precursor polymer containing low molecular weight additives, which can be converted into an objective functional material, excellent functional ceramic fibers with gradient surface layers were also developed. In this chapter, representative properties of these fibrous materials and their expected applications are described.