PROCEDE D'ELABORATION D'UNE POUDRE COMPRENANT DU CARBONE, DU SILICIUM ET DU BORE, LE SILICIUM SE PRESENTANT SOUS FORME DE CARBURE DE SILICIUM ET LE BORE SE PRESENTANT SOUS FORME DE CARBURE DE BORE ET/OU DE BORE SEUL

A method is followed to prepare a powder that includes carbon, silicon and boron, the silicon being in silicon carbide form and the boron being in boron carbide and/or free boron form. The method includes contacting a carbon-based precursor, a silicon-based precursor and a boron-based precursor BX3, X being a halogen atom, to obtain a mixture of these three precursors. The resulting mixture is subjected to laser pyrolysis. The boron-based precursor BX3 is heated, prior to the contacting step and/or simultaneously with the contacting step, to a temperature higher than the condensation temperature of the precursor.