JP4913934B2 - Oxidation resistant coating film of carbon fiber reinforced carbon composite material and repair method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxidation resistant coating film of a carbon fiber reinforced carbon composite material and a repair method thereof.
[0002]
[Prior art]
Carbon fiber reinforced carbon composite materials (hereinafter abbreviated as C / C composite materials) are lightweight and excellent in heat resistance, and are used, for example, in the nose cone and leading edge of the US space shuttle. Application to a combustor of a return engine is under consideration.
[0003]
Since this C / C composite material is a carbon material and is vulnerable to oxidation as disclosed in, for example, Japanese Patent Application Laid-Open No. 11-70617, when used in the atmosphere, as shown in a schematic diagram in FIG. It is necessary to provide an oxidation resistant coating film 2 on the surface of the / C composite material 1.
[0004]
Here, the oxidation resistant coating film 2 is generally formed by forming a SiC (silicon carbide) conversion layer 3 mainly having excellent oxidation resistance performance on the surface of the C / C composite material 1, and PVD on the conversion layer 3. The vapor deposition layer 4 of silicon carbide is formed by the (physical vapor deposition) method or the CVD (chemical vapor deposition) method, and further, the thermal expansion difference between the C / C composite material 1 and silicon carbide is formed on the surface of the vapor deposition layer 4. It forms by forming the crack seal layer 5 which consists of a glass-type material for sealing the crack which generate | occur | produces. In addition, when oxidation resistance at a temperature of 1700 ° C. or higher is required, it has been studied to coat oxide such as alumina or hafnia on silicon carbide.
[0005]
[Problems to be solved by the invention]
However, when an anti-oxidation coating film is provided on a component made of the above-mentioned C / C composite material, the component is inserted into a specific apparatus and subjected to a coating process by vapor deposition or the like. Since there are few examples where it is actually used, little research has been done on the method of repairing the oxidation-resistant coating film.
[0006]
For this reason, at present, when a part with an anti-oxidation coating film is attached to the actual machine and the damage is caused to the anti-oxidation coating film, a coating process such as a vapor deposition method is performed in the state of being attached to the actual machine. Therefore, the damaged parts are removed from the actual machine one by one and repaired.
[0007]
In addition, since the coating process by vapor deposition or the like is applied to the entire surface of the part, it is difficult to repair locally limited damage of the coating film, for example, local damage. However, all the coating layers are removed and the coating process is performed again.
[0008]
Accordingly, a first object of the present invention made in view of such a point is to provide a method for repairing an oxidation resistant coating film of a carbon fiber reinforced carbon composite material capable of easily repairing a damaged portion of the oxidation resistant coating film locally. It is in.
[0012]
[Means for Solving the Problems]
Invention oxidation resistant coating film repair method of a carbon fiber-reinforced carbon composite material as in claim 1 to achieve the above first object, the damaged portion of the oxidation resistant coating layer comprising silicon carbide which has been subjected to a carbon fiber-reinforced carbon composite material in oxidation resistant coating film a method of repairing a carbon fiber reinforced carbon composite material to repair, after filling a paste material containing a locally aluminum phosphate and alumina to the damaged portion, a paste material containing the aluminum phosphate and alumina It is characterized by firing after drying.
[0013]
According to the first aspect of the present invention, after the paste material containing aluminum phosphate and alumina is filled in the damaged portion, the paste material containing aluminum phosphate and alumina is dried and then fired to damage the oxidation resistant coating film. When the damaged part of the oxidation-resistant coating film is repaired in this way, an oxide layer can be easily formed on the damaged part with the component attached to the actual machine, and the oxidation resistance of the C / C composite material It becomes possible to fully recover the sex.
[0014]
Here, the use of paste material containing aluminum phosphate and alumina, a material containing aluminum phosphate and alumina has a high heat resistance temperature, stable in oxygen permeability is less oxygen atmosphere Among oxides, one且to form the appropriate adhesion layer between the carbonization silicon, because it can form an oxide by pre-baking can be easily filled in the injury site in liquid form, yet to be fired at a relatively low temperature (500 ° C. or less), This is because the heat treatment can be easily performed locally with a heating device such as a halogen lamp.
[0015]
Also, after filling the paste material containing aluminum phosphate and alumina, the reason for drying is to remove the moisture in the paste material, and if it is heated rapidly without removing moisture, it will be contained in the paste material This is to prevent the moisture from being foamed and voids from being formed in the oxide, and oxygen from penetrating through the voids to reduce the oxidation resistance of the damaged portion.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0017]
In the present embodiment, as shown in FIG. 1, the damaged portion 11 formed on the oxidation resistant coating film 2 applied to the C / C composite material 1 is repaired. Here, as described with reference to FIG. 5, the oxidation-resistant coating film 2 includes a silicon carbide conversion layer 3 and a vapor phase plating layer 4, and a crack seal layer made of a glass-based material formed on the vapor phase plating layer 4. 5.
[0018]
First, as shown in FIG. 2, a phosphoric acid-based alumina paste material 12 is injected and filled into the damaged portion 11 of the oxidation-resistant coating film 2 with a syringe or the like. Here, the phosphate-based alumina paste material 12 is preferably aluminum phosphate (AlPO ₄ ) 40 to 70% (molar ratio excluding the solvent), alumina (Al ₂ O ₃ ) 30 to 60% (the solvent is used). The ratio of (excluded molar ratio) is good, and a mixture of 1: 1 (molar ratio) is the best.
[0019]
Thereafter, as shown in FIG. 3, for example, after being naturally dried for about 24 hours at room temperature, the filling portion of the phosphoric acid-based alumina paste material 12 is locally heated from room temperature to 500 ° C. with a heating device such as a halogen lamp. The phosphoric acid-based alumina paste material 12 is fired. Here, the baking is performed in steps of 120 ° C. for 1 hour and 500 ° C. for 1 hour.
[0020]
In this way, as shown in FIG. 4, the phosphate-based alumina 13 is formed on the damaged portion 11 of the oxidation resistant coating film 2, and the repair process is completed.
[0021]
As described above, the C / C composite material 1 having the oxidation resistant coating film 2 in which the damaged portion 11 is repaired with the phosphoric acid-based alumina 13, and the C / C composite material having the same oxidation resistant coating film without the damaged portion, When an oxidation resistance test was performed by oxidizing at 1600 ° C. for 20 minutes, the weight reduction rate of both was 0.7% for the repaired C / C composite material 1 and the C / C composite material without damage. The reduction amount of the C / C composite material 1 subjected to the repair processing was slightly large. From this, it was confirmed that the oxidation resistant coating film 2 in which the damaged part 11 was repaired with the phosphoric acid-based alumina 13 had sufficient oxidation resistance performance.
[0022]
【Effect of the invention】
According to the oxidation resistant coating film of the C / C composite material according to the present invention, the damaged portion of the oxidation resistant coating film is repaired with a material containing aluminum phosphate and alumina, so that the heat resistant temperature is high and stable in an oxygen atmosphere. or one moderate adhesion layer between the carbonization silicon is formed, the oxidation resistance of C / C composite material can be sufficiently recovered.
[0023]
In addition, according to the method for repairing an oxidation resistant coating film of a C / C composite material according to the present invention, the damaged portion is filled with a phosphoric acid-based alumina paste material and dried and fired. Thus, an oxide layer can be formed, and the oxidation resistance of the C / C composite material can be sufficiently recovered.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an oxidation resistant coating film having a damaged portion to be repaired, illustrating an embodiment of an oxidation resistant coating film of a C / C composite material and a repair method thereof according to the present invention.
FIG. 2 is a diagram showing a state in which a damaged portion is filled with a phosphoric acid-based alumina paste material in order to repair the damaged portion of the oxidation-resistant coating film by the repair method according to the embodiment of the present invention.
FIG. 3 is a diagram showing a treatment time and a treatment temperature in a drying and firing treatment by the repair method according to the embodiment of the present invention.
FIG. 4 is a schematic view of an oxidation resistant coating film after repairing a damaged portion.
FIG. 5 is a schematic view of an oxidation resistant coating film of a C / C composite material.
[Explanation of symbols]
1 C / C composite material (carbon fiber reinforced carbon composite material)
2 Oxidation-resistant coating film 3 Conversion layer 4 Gas phase plating layer 5 Crack seal layer 11 Damaged part 12 Phosphate-based alumina paste material 13 Phosphate-based alumina

Claims (1)

In the method of repairing an oxidation resistant coating film of a carbon fiber reinforced carbon composite material, repairing a damaged portion of the oxidation resistant coating film containing silicon carbide applied to the carbon fiber reinforced carbon composite material,
A carbon fiber reinforced carbon composite material characterized in that after the paste material containing aluminum phosphate and alumina is locally filled in the damaged portion, the paste material containing aluminum phosphate and alumina is dried and fired. Oxidation-resistant coating film repair method.

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