Boron-containing preceramic blend and fiber formed therefrom

摘要

A process for producing boron-containing ceramics such as boron carbide and boron nitride comprises pyrolyzing a blend of a precarbonaceous polymer such as polyacrylonitrile and a boron-containing polymer such as that formed by the reaction of a borane with a Lewis base. Pyrolyzation in an inert atmosphere yields boron carbide while pyrolyzation in a reactive gas burns away the precarbonaceous polymer and yields a ceramic comprising the reaction product of boron and the pyrolyzation gas. Boron nitride ceramics are formed by pyrolyzing the preceramic blend in ammonia.