Protecting parts made of carbon-containing composite material from oxidation
A method of protecting a part made of carbon-including composite material against oxidation, the method including a) applying a coating composition on at least a portion of the outside surface of the part, the coating composition being in the form of an aqueous suspension including: a metallic phosphate; a powder of a compound comprising titanium; and a B 4 C powder; and b) applying heat treatment to the coating composition applied during step a) with a treatment temperature lying in the range 330° C. to 730° C. being imposed during the heat treatment in order to obtain a coating on the outside surface of the part, the coating including a first phase in which the metallic phosphate is in crystalline form and a second phase in which the metallic phosphate is in amorphous form.
1. A method of protecting a part made of carbon-including composite material against oxidation, the method comprising:
a) applying a coating composition on at least a portion of an outside surface of the part, the coating composition being in the form of an aqueous suspension comprising:
a metallic phosphate;
a powder of a compound comprising titanium; and
a B 4 C powder; and
b) applying heat treatment to the coating composition applied during step a) with a treatment temperature lying in the range 330° C. to 730° C. being imposed during the heat treatment in order to obtain a coating on the outside surface of the part, the coating comprising a first phase in which the metallic phosphate is in crystalline form and a second phase in which the metallic phosphate is in amorphous form.
2. The method according to claim 1 , wherein the coating composition also comprises an organic dispersing agent.
3. The method according to claim 2 , wherein the organic dispersing agent is an alkoxylated acetylenic polyol.
4. The method according to claim 1 , wherein the titanium-comprising compound is selected from the group consisting of titanium metal, titanium diboride, titanium carbide, titanium dioxide, and mixtures thereof.
5. The method according to claim 4 , wherein the coating composition includes a powder of titanium metal and/or a powder of titanium diboride.
6. The method according to claim 1 , wherein the coating composition includes an aluminum phosphate.
7. The method according to claim 1 , wherein the coating composition further includes a self-healing vitreous compound.
8. The method according to claim 1 , wherein the coating composition comprises, before step a):
the metallic phosphate at a content by weight lying in the range 27% to 36%;
the B 4 C powder at a content by weight lying in the range 11.5% to 21%; and
the powder of the titanium-comprising compound at a content by weight lying in the range 8% to 18%.
9. The method according to claim 8 , wherein the coating composition comprises, before step a):
aluminum phosphate at a content by weight lying in the range 27% to 36%;
the B 4 C powder at a content by weight lying in the range 11.5% to 21%;
the powder of the titanium-comprising compound at a content by weight lying in the range 8% to 18%;
an alkoxylated acetylenic polyol at a content by weight lying in the range 0.1% to 1.5%; and
water at a content by weight lying in the range 33% to 50%.
10. The method according to claim 1 , wherein at least one internal protection layer is formed before step a) by impregnating at least a portion of the part made of composite material with an impregnation composition including a metallic phosphate.
11. The method according to claim 10 , wherein the impregnation composition comprises aluminum phosphate.
12. The method according to claim 1 , wherein the treatment temperature is imposed during the heat treatment for a duration greater than or equal to 1 hour.