Abstract: Ceramic fibers characterized by comprising a quaternary system composed of Si, C, N, and O and having a specific resistance of 10.sup.6 to 10.sup.10 .OMEGA..multidot.cm, and a suitable process for producing the ceramic fibers characterized by reacting infusible polycarbosilane fibers with ammonia and further heat treating the reaction product in an inert gas.

Abstract: A preform wire for fiber reinforced metal composite consisting of a metal/silicon carbide fiber composite material is light in weight and excellent in strength and elasticity, and can be easily obtained by impregnating a silicon carbide fiber bundle with a molten metal which is kept vibrated by means of an ultrasonic wave vibration apparatus having a hole for cooling water or a cooling-water jacket located at the node of the half-wavelength of the ultrasonic wave created by the vibration apparatus.

Abstract: A method for manufacturing a silicon carbide fiber reinforced glass composite, which comprises either dipping silicon carbide fibers in molten glass in a tank, the molten glass being given wave vibration of 10-30 KHz by a supersonic vibrator provided with a cooling means to unravel the silicon carbide fibers and have the molten glass permeated therebetween, or plasma melt ejecting glass powder onto silicon carbide fibers to obtain a silicon carbide fiber/glass preform, molding the preform into a predetermined form and then subjecting the molded preform to thermal molding thereby to manufacture the silicon carbide fiber reinforced glass composite in the form of a molding.

Abstract: An electromagnetic wave absorber comprising a surface layer made of a composite of fibers having an electrical specific resistance of more than 10.sup.4 .OMEGA.cm and a resin, and a wave absorbing layer made of a composite containing silicon carbide fibers having an electrical specific resistance of from 10.sup.-2 to 10.sup.4 .OMEGA.cm. The composite used in the surface layer may be prepared, for example, by impregnating the resin in between the fibers after they have been treated to be a woven cloth, mat or felt or unidirectionally arranged fibers. If a wave absorbing layer is to be made of a composite containing the silicon carbide fibers and a resin, then the composite may be prepared in the same way as above.

Abstract: A method for manufacturing a silicon carbide fiber reinforced glass composite, which comprises either dipping silicon carbide fibers in molten glass in a tank, the molten glass being given wave vibration of 10-30 KHz by a supersonic vibrator provided with a cooling means to unravel the silicon carbide fibers and have the molten glass permeated therebetween, or plasma melt ejecting glass powder onto silicon carbide fibers to obtain a silicon carbide fiber/gass preform, molding the preform into a predetermined form and then subjecting the molded preform to thermal molding thereby to manufacture the silicon carbide fiber reinforced glass composite in the form of a molding.

Abstract: A preform wire for fiber reinforced metal consisting of a metal/silicon carbide fiber composite material is light in weight and excellent in strength and elasticity, and can be easily obtained by impregnating a silicon carbide fiber bundle with a molten metal which is kept vibrated by means of an ultrasonic wave vibration apparatus having a cooling means.

Abstract: A process for the surface treatment of inorganic fibers for reinforcing titanium or nickel, comprising the steps of coating the surface of inorganic fibers with an aqueous or organic solvent solution containing a titanate, borate, tetralkylammonium hydroxide and, if desired, dextrin and then heat treating the coated fibers at a high temperature in an inert or non-oxidizing atmosphere. In one embodiment, the heat treated inorganic fibers is further subjected to ionic or chemical plating with nickel.

Abstract: A process for producing carbon fibers from various kinds of pitches wherein the calorific values of the pitches are measured and the pitches thereafter subjected to a suitable procedure for producing carbon fibers therefrom depending on their measured calorific value.

Abstract: A process for producing a composite graphite material in a molded form having high density and tensile strength as well as impermeability, comprising the steps of mixing expanded graphite material with oxidized graphite material as the binder and compression molding the resulting mixture. In one embodiment, this invention relates to the composite graphite material produced by said process.

Abstract: A process for producing flexible graphite material comprises incorporating expanded graphite material with boric acid, compression molding the resulting mixture and, if desired, heating the resulting molding while under compression. This invention also relates to the flexible graphite material produced by the process.