Microtexture and structure of boron nitride fibres by transmission electron microscopy, X-ray diffraction, photoelectron spectroscopy and Raman scattering

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 340; no. 1; pp. 181 - 192
• Main Authors: Vincent, H, Chassagneux, F, Vincent, C, Bonnetot, B, Berthet, M.P, Vuillermoz, A, Bouix, J
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-01-2003; Elsevier
• Subjects: 2,4,6-tris(methylamino)borazine; BN fibres; Chemical synthesis; combustion synthesis; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Materials synthesis; materials processing; Microstructure; Physics; Raman scattering; TEM; XPS; 2,4,6-tris(methylamino)borazine; XPS; Microstructure; Raman scattering; TEM; BN fibres; Scanning electron microscopy; Raman spectra; Inorganic compounds; Boron nitrides; Melt spinning; XRD; Experimental study; Texture; Tensile strength; Fibers; Transmission electron microscopy; Property structure relationship; Chemical synthesis; X-ray photoelectron spectra
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(02)00185-5

Continuous boron nitride fibres have been fabricated by melt spinning and pyrolysis of poly[2,4,6-tris(methylamino)borazine]. The longitudinal mechanical properties depend on mechanical stress and temperature applied during the conversion process. High-performance and low-performance fibres were characterized in order to find relationship between structure and physical properties. In all the cases, photoelectron spectroscopy (XPS) analysis proves that the chemical composition of the fibre is close to stoichiometric BN. The crystallite sizes were measured by means of X-ray diffraction (XRD) and Raman techniques. Cross-sections of separated fibres were investigated by high-resolution electron microscopy (HREM) and transmission electron microscopy (TEM). All the BN fibres have a hexagonal turbostratic structure. With increasing stress and temperature, the tensile strength and the elastic modulus increase. In the high-performance fibres, the 002 layers with an increased distance (about 0.35 nm) showed a mean stacking sequence near to graphite and a preferred orientation of the 002 layers parallel to the fibre axis.