Silicon carbide fibres are of prime interest in the reinforcement of ceramic matrix composites for aerospace applications. However, in order to be competitive on the civil aircraft market, these fibres should present the highest available performance at an affordable price. There are three generations of SiC fibres, each including several varieties. Their thermal stability as well as their price increase when both the residual oxygen and free carbon concentration decrease. The features of 12 different fibres are first presented including their chemical composition as measured by electron probe microanalysis and microstructure as determined by XRD, TEM, NMR and RAMAN spectroscopy. The reactivity of the fibres with chlorine atmospheres were studied and correlated to their composition and microstructure. With such a treatment, the silicon of the fibres reacts with chlorine thus etching its surface in the form of gaseous silicon chlorine. The carbide derived carbon (CDC) layer hence formed is micro-porous allowing easy diffusion of gases. The growth kinetics of the CDC layer is thus linear with time but depends upon the composition of the fibre. The apparent activation energies deduced from the measured kinetic constants are used to compare the fibres and classify them.
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