Abstract: A siloxane composition, comprising from 70 to 99 parts by weight of a solid particulate having a median particle size of from 0.1 to 3000 ?m and from 1 to 30 parts by weight of a binder having a median particle size of from 5 to 250 ?m, wherein the composition is a powder and the binder comprises a siloxane resin having the formula: (R13SiO1/2)w(R12SiO2/2)x(R1SiO3/2)y(SiO4/2)z, wherein each R1 is independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, —O?NR2R3, —OR2, —O—R4—OR2, and an epoxy-substituted organic group, wherein R2 is C1 to C8 hydrocarbyl, R3 is R2 or —H, R4 is hydrocarbylene, w+x+y+z=1, y/(w+x+y+z) is at least 0.67, and the siloxane resin has a softening point of from 30 to 115° C.; an agglomerate, and a method preparing the agglomerate.

Abstract: This invention pertains to a method for production of polycrystalline ceramic fibers from silicon oxycarbide (SiCO) ceramic fibers wherein the method comprises heating an amorphous ceramic fiber containing silicon and carbon in an inert environment comprising a boron oxide and carbon monoxide at a temperature sufficient to convert the amorphous ceramic fiber to a polycrystalline ceramic fiber. By having carbon monoxide present during the heating of the ceramic fiber, it is possible to achieve higher production rates on a continuous process.

Abstract: A process for the preparation of substantially polycrystalline silicon carbide fibers is provided. The fibers may be fabricated to have a small diameter and are thermally stable at high temperatures. The process is carried out by initially forming fibers from a preceramic polymeric precursor comprising methylpolysilane resins. The fibers are then infusibilized to render them nonmelting followed by a pyrolysis step in which the fibers are heated to a temperature in excess of 1600.degree. C. in a nonoxidizing atmosphere to form substantially polycrystalline silicon carbide fibers. The substantially polycrystalline silicon carbide fibers which are formed by the process of the present invention have at least 75% crystallinity and have a density of at least about 2.9 gm/cm.sup.3. The polymeric precursor or the fibers contain, or have incorporated therein, at least about 0.2% by weight boron.