Abstract: A method for forming a polycrystalline ceramic fiber which comprises blending about 5 to about 25 weight percent polymer, about 70 to about 95 weight percent silicon carbide powder and greater than 1 weight percent sintering aid; forming a fiber from the blend; and sintering the formed fiber. Preferably, the sintering aid is boron carbide. In addition, the fiber is preferably pre-sintered at a first temperature of from about 1700.degree. C. to 2300.degree. C. and then subsequently sintered at a second temperature of approximately 2000.degree. C. to about 2300.degree. C.

Abstract: A glassy coated sintered non-oxide ceramic fiber produced by an in situ oxidation chemical reaction. A process to produce a protective glassy coating on ceramic fibers by heating the non-oxide ceramic fibers in the presence of boron and atmosphere containing oxygen.

Abstract: A high temperature, preferably polycrystalline, ceramic fiber having a selectable diameter of between 1 and 200 microns. The fiber is stable in an inert atmosphere at a temperature above about 1700.degree. C. and is often stable even in air at a temperature above 1500.degree. C. The fiber comprises a sintered ceramic powder having a maximum particle size less than the diameter of the fiber and an average particle size less than 0.2 times the diameter of the fiber. The ceramic powder is also stable in an inert atmosphere at a temperature above about 1700.degree. C. At least 90% of the ceramic is selected from borides, nitrides, carbides, and silicides. The fiber is characterized by a smooth surface and is preferably out of round.The invention further comprises a textilable sinterable filament, comprising a flexible polymer matrix containing high temperature sinterable ceramic powder particles. The ceramic powder particles are selected from ceramic borides, nitrides, carbides, and silicides.

Abstract: A high temperature, preferably polycrystalline, ceramic fiber having a selectable diameter of between 1 and 200 microns. The fiber is stable in an inert atmosphere at a temperature above about 1700.degree. C. and is often stable even in air at a temperature above 1500.degree. C. The fiber comprises a sintered ceramic powder having a maximum particle size less than the diameter of the fiber and an average particle size less than 0.2 times the diameter of the fiber. The ceramic powder is also stable in an inert atmosphere at a temperature above about 1700.degree. C. At least 90% of the ceramic is selected from borides, nitrides, carbides, and silicides. The fiber is characterized by a smooth surface and is preferably out of round.The invention further comprises a textilable sinterable filament, comprising a flexible polymer matrix containing high temperature sinterable ceramic powder particles. The ceramic powder particles are selected from ceramic borides, nitrides, carbides, and silicides.

Abstract: Dense, strong, composite materials are produced from mixtures of silicon and silicon carbide. The composite materials are characterized by a mixture of finely-divided silicon carbide in a substantially continuous matrix of silicon. The composite materials contain from about 40 to about 60 percent by volume silicon carbide and from about 60 to about 40 percent by volume silicon. The composite materials are produced by initially producing a finely-divided silicon carbide starting component and forming the component into a green body of the desired shape. The green body is subsequently impregnated with molten silicon in the absence of any substantial amount of carbon. Suitably, a thermoplastic resin binder may be added to the silicon carbide starting material to aid in forming the green body. The impregnation step may be carried out by surrounding the green body with finely-divided silicon metal and heating the covered body to a temperature above the melting point of silicon.

Abstract: Infusible cured phenolic resin fibers of the present invention have a birefringence of at least 2.times.10.sup.-3 with the x-ray diffraction pattern of the fibers showing an amorphous halo. The tenacity of infusible cured phenolic resin fibers is significantly increased by subjecting the fibers to sufficient longitudinal tension as to cause at least about 30% elongation of the fibers. The Young's modulus of elasticity of the fibers is also significantly increased thereby. Preferably the resulting stretched infusible cured phenolic resin fibers have a tenacity of at least about 4 g./den.

Abstract: Phenolic resins employed for melt spinning fibers are modified by the incorporation therein of from about 5% to about 30% of an aliphatic nylon, whereby the melt spinning characteristics of the phenolic resins are improved and the tenacity of the melt spun fibers is increased.

Abstract: A flame resistant cloth or fabric comprising synthetic fibers prepared from resin condensation products of phenols and aldehydes which can be fiberized and cured. These fabrics may include blends of phenolic resin fibers with other fire resistant fibers such as wool, silk, polyamide fibers, polyacrylonitrile fibers, mineral and glass fibers, among others.