Boron nitride fibers: Preparation, properties and applications

Boron nitride fibers have been synthesized by the chemical reaction of the boric oxide fibers in an ammonia atmosphere. The processing is basically divided into three steps: making boric oxide fibers, nitriding and graphitizing the boron nitride fibers. The nitriding of boric oxide fibers depends on the fiber diameter, nitriding temperature, heating rate, and atmosphere. Under our conditions, the processing of boron nitride fibers has been optimized. Boron nitride fibers after nitriding at 100{dollar}spcirc{dollar}C contain 6-8% boric oxide as impurity. High purity boron nitride fibers have been synthesized with less then 1% boric oxide by graphitizing.; The experimental results indicate that boron nitride fibers exhibit highly electrical and corrosive resistance, thermal stability, good mechanical properties. Boron nitride fibers can be used as: reinforcing media; filtrating and insulating material at elevated temperatures.; Boron nitride/Kaowool felt has been designed and processed. The felt property investigation indicated that the felt has good flexibility, strength, very high resistivity at both room and elevated temperatures.