The invention relates to a method of making a refractory carbide layer on the accessible surface of a C/C composite material, the method including a step consisting in placing the composite material in contact with a reactive composition in solid form that contains an atomic proportion greater than or equal to one-third and less than or equal to 95% of a metal that is a precursor of a determined carbide having a melting temperature greater than 2000° C., and an atomic proportion of silicon that is greater than or equal to 5% and less than or equal to two-thirds. The method further includes a step consisting in impregnating the accessible surface of the C/C composite material with the reactive composition melted at a temperature that is greater than or equal to the melting temperature of the metal that is a precursor of a determined carbide.