Abstract: A process is disclosed for producing a non-woven boron nitride (BN) fiber felt. Boron nitride fibers are blended with a lesser amount of boron oxide fibers and a nondissolving, anhydrous liquid medium to form a homogeneous slurry. The slurry is deposited on the moving screen of a Fourdrinier machine where the liquid content is gradually reduced until sufficient fiber to fiber contact is made to provide internal cohesiveness, to form a felt. The felt may be further treated by heating it in an anhydrous gas atmosphere at a sufficient temperature to soften the boron oxide binder to fuse the BN fibers together, and then converting the interstitial boron oxide into boron nitride. The resulting boron nitride-bonded boron nitride felt may be used as an electric cell separator in a lithium sulfide battery.

Abstract: A process is disclosed for producing non-woven, yet internally cohesive, boron nitride fiber batts, suitable for use as an electric cell separator in a lithium-sulfide battery. Molten boron oxide is centrifugally spun into strands and attenuated by an annular gas stream into fibers at a controlled relative humidity. The fibers are funnelled into a chamber and subjected to a turbulent air flow, which causes random orientation and intertwining of the fibers, resulting in multiple mechanical bonds thereamong. The compacted boron oxide fiber bundle thus produced is heated in an anhydrous ammonia atmosphere to convert boron oxide in the fibers into boron nitride (BN).

Abstract: A process is disclosed for producing a non-woven, boron nitride-bonded boron nitride fiber mat, suitable for use as an electric cell separator in a lithium-sulfide battery. A web having a combination of structural boron nitride (BN) fibers and interstitial, thermally bondable boron oxide (B.sub.2 O.sub.3) fibers is passed through the nip of a pair of cooperating calender rolls at an appropriate temperature and pressure to soften the boron oxide binder throughout the web to fuse the BN fibers together. The interstitial boron oxide then is heated in an anhydrous ammonia atmosphere to convert it into boron nitride.

Abstract: A process is disclosed for producing a non-woven, boron nitride-bonded boron nitride fiber mat, suitable for use as an electric cell separator in a lithium-sulfide battery. Molten boron oxide is centrifugally spun into strands and attenuated by an annular gas stream into fibers which are compacted at a controlled relative humidity into a bundle and heated in an anhydrous ammonia atmosphere to convert boron oxide in the fibers to boron nitride (BN). The BN fibers are blended with a lesser amount of boron oxide fibers and a nonaqueous liquid medium to form a slurry. The slurry is processed through a Fourdrinier machine to form a felt; and, the felt is calendered by passing it through the nip of a pair of calender rolls at an appropriate temperature and pressure to soften the boron oxide binder to fuse the BN fibers together. The interstitial boron oxide then is converted to boron nitride.