Boron carbide

Abstract

This disclosure describes the process for producing an apparently amorphous porous boron carbide having a mean particle size less than 1 micron in diameter, effective pore sizes on the order of 30 Angstrom units, and surface areas on the order of 100 m.sup.2 /gr and greater. The process involves the gaseous phase reaction of acetylene (C.sub.2 H.sub.2) with diborane (B.sub.2 H.sub.6). The reaction is produced in a closed chamber initiated by an appropriate igniting device, such as a hot wire. This disclosure defines an optimum ratio of four parts diborane to one part acetylene and it describes the operating conditions under which the reaction occurs and the variation in physical properties and yield resulting from changes of ratio of the constituents. It also describes modification of the present batch process to a continuous production process. Typical uses for the material in its basic or altered form are described, such as a catalyst for gas-solid reactions, as a catalyst-supporting substrate for certain transition metals and other catalytic materials, as a gelling agent or grease thickener, as a thermal neutron absorber, either neat or in admixture with oils, etc., as a high temperature insulation material and as a fluidized bed heat exchange medium.