At. Hemida et al., CONTINUOUS SIC-BASED MODEL MONOFILAMENTS WITH A LOW FREE CARBON CONTENT .2. FROM THE PYROLYSIS OF A NOVEL COPOLYMER PRECURSOR, Journal of Materials Science, 32(9), 1997, pp. 2367-2372
Ouasi stoichiometric model SiC mono-filaments (C/Si atomic ratio appro
ximate to 1.02) with still some free carbon (approximate to 3 mol %) a
nd residual oxygen have been produced from a novel copolymer precursor
, itself prepared from methylphenyldichlorosilane and 2,4-dichloro-2,4
-disilapentane. The continuous green fibre was melt spun at 230 degree
s C, cured by electron-beam irradiation, and pyrolysed under argon at
temperatures, T-p, in the range 1000-1600 degrees C. The fibre remaine
d nanocrystalline at high temperature with the SIC grain size growing
from 1.5 nm to 7.3 nm when T-p was raised from 1400 degrees C to 1600
degrees C. Its Young's modulus continuously increased as T-p was raise
d (with E = 320 GPa for Tp = 1400 degrees C), whereas its tensile stre
ngth at room temperature underwent a maximum for T-p = 1200 degrees C
(sigma(R) approximate to 1850 MPa for L = 10 mm and d approximate to 2
0 mu m).