Boron-modified polysilazane as a novel single-source precursor for SiBCN ceramic fibers: synthesis, melt-spinning, curing and ceramic conversion

Samuel Bernard (1, 2) , M. Weinmann (2) , P. Gerstel , P. Miele (1) , F. Aldinger (2)

1 LMI - Laboratoire des Multimatériaux et Interfaces
2 Max-Planck-Institut für Metallforschung

A novel boron-modified polysilazane functionalised with Si- and N-bonded methyl groups has been synthesised and characterised by means of FT-IR and NMR spectroscopies as well as elemental analysis. Both Si- and N-bonded methyl groups inhibited extensive cross-linking to yield a tractable polymer which was successfully processed into polymer green fibers by a melt-spinning process. After the shaping processing, the N-bonded methyl groups offered the capability of facile polymer cross-linking in an ammonia atmosphere at 200 °C to increase the ceramic yield of the polymer and avoid inter-fiber fusion. The as-obtained cured fibers were subsequently pyrolysed at 1400 °C in a nitrogen atmosphere to provide amorphous and stable Si3.0B1.0C5.0N2.4 ceramic fibers with ca. 1.3 GPa in tensile strength, ca. 170 GPa in Young's modulus and ca. 23 μm in diameter.

Domains: Chemical Sciences; Chemical Sciences; Material chemistry; Engineering Sciences [physics]

Samuel Bernard, M. Weinmann, P. Gerstel, P. Miele, F. Aldinger. Boron-modified polysilazane as a novel single-source precursor for SiBCN ceramic fibers: synthesis, melt-spinning, curing and ceramic conversion. Journal of Materials Chemistry, 2005, 15 (2), pp.289. ⟨10.1039/B408295H⟩. ⟨hal-02617034⟩