JPH05310404

PURPOSE:To produce boron nitride or boron nitride fibers simply without complicated process by no use of borazines or decaborane which are expensive and chemically unstable. CONSTITUTION:An adduct of a boron trihalide such as boron trichloride to a nitrile such as acetonitrile or benzonitrile and ammonium chloride or an amide hydrochloride are heated at about 125 deg.C in the presence of a boron trihalide to prepare the precursor of boron nitride. The resultant boron nitride precursor is heat-treated at about 1,500 deg.C in a non-oxidative atmosphere such as nitrogen gas to give boron nitride. Or, the boron nitride precursor is dissolved in a solvent such as N,N-dimethyl-formamide and the solution is extruded into fibers and the fibers are heat-treated at about 1,500 deg.C in a non-oxidative atmosphere such as nitrogen gas to give boron nitride fibers.