Abstract: Particulate material, composites containing said material, and a method of making said particulate material. The material is composed of at least about 85% (number basis) of regular, well-defined ellipsoidal particles having a size less than about 25 microns, at least 90% and 50% by weight of the particles being less than about 15 and 10 microns in size respectively, a surface area of about 0.75 to about 2.5 square meters per gram and a specific gravity of about 2 to 3. The composites contain this particulate material and up to about 99% of one or more polymeric media. The particulate material is produced by subjecting a diverse mixture of flyash particles to dry air classification in an air classifier controlled to recover particulate particles as described above.

Abstract: Particulate material, composites containing said material, and a method of making said particulate material. The material is composed of at least about 85% (number basis) of regular, well defined ellipsoidal particles and has a particle size less than about 25 microns, about 90% and 50% by weight of the particles being less than about 15 and about 10 microns respectively in size and has a specific surface in the range of about 0.75 to about 2.5 m.sup.2 /gram as well as a specific gravity of about 2 to about 3. The composites contain said particulate material and up to about 99% of one or more polymeric media. The particulate material may be prepared by subjecting a diverse mixture of flyash particles to dry air classification in an air classifier controlled to recover particulate solids as described above.

Abstract: A reinforced carbon article which comprises a carbon fiber shape bonded by a carbon binder and having incorporated within said article a friction modifier, e.g., the in situ reaction product of carbon and a boron containing additive which comprises a material selected from the group consisting of boron, boron nitride, boron silicide and refractory metal borides; and a process of making such an article which comprises forming a carbon fiber shape, dispersing a boron containing additive within at least a portion of said carbon fiber shape, impregnating the carbon fiber shape with a carbonizable binder, and heating the shape to carbonize the binder and to form in situ the reaction product of carbon and the boron containing additive.