Method of protecting a composite material part against oxidation

A method of protecting a carbon-containing composite material part against oxidation, the method comprising:

• applying a first coating composition in the form of an aqueous suspension on an outside surface of the part, the first coating composition comprising:
• a metallic phosphate;
• a powder of an ingredient comprising titanium;
• and
• a powder of B4C;
• subjecting the applied first coating composition to a first heat treatment in order to obtain a first coating on the outside surface of the part;
• applying a second coating composition on the first coating composition, the second coating composition comprising:
• an aqueous suspension of colloidal silica;
• a powder of borosilicate glass;
• and
• a powder of TiB2;
• and
• subjecting the applied second coating composition to a second heat treatment in order to obtain a second coating on the first coating,
• wherein the first coating obtained on the outside surface of the part has a thickness from 40 μm to 80 μm.