Wenderoth, Lind & Ponack
Boron nitride fiber and process for production thereof
 A boron nitride fiber comprising hexagonal and/or turbostratic boron nitride having C planes oriented substantially parallel to the fiber axis and a degree of orientation of 0.74 or above can be obtained by heating an adduct between a boron trihalide such as boron trichloride or the like and a nitrile compound such as acetonitrile, benzonitrile or the like, and an ammonium halide or a primary amine hydrohalide in the presence of a boron trihalide at around 125.degree. C. to form a boron nitride precursor, dissolving the boron nitride precursor in a solvent such as N,N'-dimethyl formamide or the like, capable of dissolving the precursor, spinning the solution to obtain a boron nitride precursor fiber, heat-treating the precursor fiber in an inert gas atmosphere and then in an ammonia gas atmosphere to obtain a boron nitride fiber, and heat-treating the boron nitride fiber with a tensile stress being applied to the fiber. The boron nitride fiber of the present invention has a degree of orientation of 0.74 or above and therefore has a high tensile strength. 
Tokuyama Corporation
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D01F Y10T Y10T
inventional additional additional
Yoshio Hiroya
Okano Yamashita