Preparation and properties of hexagonal boron nitride fibers used as high temperature membrane filter

•h-BN fibers were successfully fabricated using H3BO3 and C3H6N6 as raw materials.•The obtained BN fibers were polycrystalline and uniform in morphology.•It exhibited good oxidation resistance and low thermal expansion coefficient.

Hexagonal boron nitride fibers were synthesized via polymeric precursor method using boric acid (H3BO3) and melamine (C3H6N6) as raw materials. The precursor fibers were synthesized by water bath and BN fibers were prepared from the precursor at 1873 K for 3 h in flowing nitrogen atmosphere. The crystalline phase and microstructures of BN fibers were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy. The results showed that h-BN fibers with uniform morphology were successfully fabricated. The well-synthesized BN fibers were polycrystalline with 0.4–1.5 μm in diameter and 200–500 μm in length. The as-prepared samples exhibited good oxidation resistance and low thermal expansion coefficient at high temperature.

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