JP4109732B2 - Manufacturing method of self-healing type high temperature member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a gas turbine, and jet engine, a method for producing a self-healing type high-temperature member for use in a high temperature oxidizing atmosphere.
[0002]
[Prior art]
In recent years, development research for improving thermal efficiency has been vigorously continued in prime movers such as gas turbines and jet engines. One of the most effective techniques for improving thermal efficiency is to raise the temperature of the combustion gas.
[0003]
Therefore, the base material of the high temperature member such as the moving blade, the stationary blade, the combustor, and the shroud that is in direct contact with the high temperature combustion gas is required to be improved so that it can be used even in a severer high temperature environment.
[0004]
However, when metals, carbon (including graphite, carbon / carbon fiber composites), and non-oxide ceramics are used in a high-temperature oxidizing atmosphere, there is a problem that the surface exposed to the oxidizing atmosphere is oxidized.
[0005]
On the other hand, oxide ceramics have the advantage of being able to reduce this oxidation and at the same time have excellent heat resistance and chemical stability, but there is a problem of poor toughness, so there is a problem of lack of reliability. is there.
[0006]
From the viewpoint of solving such problems, improvements have been attempted from the following points (A) and (B).
(A) An attempt to improve oxidation resistance by alloying.
(B) Using metal, ceramic, and carbon with excellent mechanical strength and toughness as the base material, coating the surface with a material with excellent oxidation resistance, and separating the functions to achieve both mechanical properties and environmental resistance Is an attempt. An example in which ceramic is coated on the metal surface is disclosed in Japanese Patent Application No. 4-214422. An example in which an oxide ceramic is coated on a silicon nitride ceramic surface is disclosed in Japanese Patent Publication No. 5-8152. An example in which carbon is coated with ceramic is disclosed in JP-A-58-12567.
[0007]
[Problems to be solved by the invention]
However, in the case of a high-temperature member comprising the above-described base material, when used in a high-temperature oxidizing atmosphere such as a gas turbine or a jet engine, as described in (Ap) and (Bp) below, mechanical strength and acid resistance There is a problem that the chemical properties are insufficient.
Although the (Ap) alloying method improves the oxidation resistance, it naturally has the disadvantage of simultaneously reducing the mechanical strength. In addition, since many ceramics are chemically stable, there is a drawback that the use of many alloy elements is limited. In summary, the alloying method has a problem that it is difficult to achieve both mechanical strength and oxidation resistance.
(Bp) On the other hand, in the method of coating an oxidation-resistant material on the surface of a base material, since the oxidation-resistant ceramic coating layer is generally brittle, a thermal shock caused by a rapid temperature change or a difference in thermal expansion from the base material There is a problem that cracks easily occur due to thermal stress caused by.
[0008]
Precisely, this crack causes a problem that the metal, non-oxide ceramic, and carbon base material are exposed and exposed to a high-temperature oxidizing atmosphere to cause the base material to oxidize remarkably and cause a reduction in strength of the base material. In addition, such problems may cause troubles that hinder use.
[0009]
The present invention has been made in view of the above circumstances, and even when an oxide layer or an oxidation-resistant coating layer formed on the substrate surface is cracked and the substrate is exposed, the crack is repaired with Al oxide. the self-healing, and to provide a method for producing a self-healing type high-temperature member which is compatible with mechanical strength and oxidation resistance.
[0010]
[Means for Solving the Problems]
The invention corresponding to claim 1 includes a fiber member forming step of forming a fiber member by weaving a plurality of fibers containing at least ceramics or carbon as a main component , and at least ceramics or carbon as a main component in the fiber member. An impregnation step of impregnating the slurry, and solid solution or dispersion of Al compound in the fiber member impregnated with the slurry, and sintering the slurry and Al together with the fiber member to form a matrix member in the fiber member It is a manufacturing method of the member for self-repair type | mold high temperature including the matrix member formation process to form .
[0017]
The invention corresponding to claim 2 is the self-healing type high temperature member manufacturing method corresponding to claim 1 , wherein the fiber member and the matrix member are both self-healing type high temperature mainly composed of SiC. It is a manufacturing method of the member for use.
[0018]
Furthermore, the invention corresponding to claim 3 is the method of manufacturing a self-repairing type high temperature member corresponding to claim 1 or claim 2 , wherein the fiber member and the matrix member are formed by machining after forming the matrix member. A self-repairing type high temperature process comprising: a molding process for molding a base material comprising a predetermined size; and a coating layer forming process for forming an oxidation-resistant coating layer on the surface of the molded base material by a CVD method. It is a manufacturing method of the member for use.
[0019]
According to a fourth aspect of the present invention, in the method of manufacturing a self-repairing type high temperature member corresponding to the third aspect , the CVD method is caused by a reaction between a supplied HCl gas and Al in the matrix member. Al chloride gas is used as a raw material for the oxidation-resistant coating layer, and the oxidation-resistant coating layer is a method for producing a self-repairing type high-temperature member that is Al ₂ O ₃ .
[0020]
The base material contains ceramic alone or carbon alone or a total of both within a range of ˜99.9% by weight. As other subcomponents, high melting point metals such as W, Mo, Ta, and Nb, and intermetallic compounds such as NiAl, NbAl, MoSi, and TiAl can be used as appropriate. It has become.
[0021]
Here, examples of the ceramic include carbide ceramics represented by SiC, nitride ceramics represented by Si ₃ N ₄ , oxidation of Al ₂ O ₃ , MgO, SiO ₂ , Y ₂ O ₃ , ZrO _{2, and the} like. Physical ceramics can be applied, and the same applies to fiber members and matrix members.
[0022]
As the Al compound, for example, intermetallic compounds such as TiAl and NiAl, carbide ceramics such as AlC, nitride ceramics such as AlN, and the like are applicable.
[0023]
Moreover, it is preferable that the content rate of Al in a base material exists in the range of 0.1-30 weight%, and exists in the range of 10-30 weight% from a viewpoint of expressing a self-repair function rapidly. Note that the base material has an Al content of 0.1 to 30% by weight within the range and an Al content of 10 to 30% by weight on the surface. In view of maintaining high high-temperature strength and providing high oxidation resistance on the surface.
[0024]
Examples of the Al oxide include composite oxide ceramics such as Al2 O3, Al2 O3.SiO2, Al2 O3.MgO, and Al2 O3.ZrO2.
The fiber member contains ceramic alone or carbon alone or a total of both within a range of ˜99.9% by weight.
The matrix member contains ceramic alone or carbon alone or a total of both within a range of ˜99.9% by weight.
The Al content of the matrix member is preferably in the range of 0.1 to 30% by weight, and preferably in the range of 10 to 30% by weight from the viewpoint of rapidly developing the self-repair function.
[0026]
In addition, it goes without saying that the value obtained by weighted average with the weight of each member as the weight is the content of ceramics in the base material described above with respect to the content of ceramics in each of the fiber member and the matrix member. .
(Function)
Therefore, in the invention corresponding to claim 1, since the base material contains Al or an Al compound by taking the above-described means, the free energy of formation of the oxide is small in a high-temperature oxidizing atmosphere (oxygen and Al which is easy to bond) preferentially reacts with oxygen, and an Al-based oxide is formed on the surface. Since this Al-based oxide has a low diffusion rate of oxygen therein, the generation rate of the oxide can be reduced. That is, an Al-based oxide is formed on the surface to reduce the oxidation rate.
[0027]
Further, even if the Al-based oxide is cracked and the surface of the base material is exposed, Al in the base material preferentially reacts with oxygen, and an Al-based oxide is formed on the surface. Therefore, this Al-based oxide prevents rapid oxidation from the exposed part due to cracking.
[0028]
In this way, even when the Al-based oxide formed on the surface of the base material is cracked and the base material is exposed, it has a self-healing function to repair the crack by re-forming the Al-based oxide, Both mechanical strength and oxidation resistance can be achieved.
[0035]
Furthermore, the invention corresponding to claim 1 is a structure in which the matrix member is held in the fiber member, so that a self-healing type high temperature member made of a fiber member or matrix member that can be expected to improve mechanical strength and toughness is provided. It can be manufactured easily and reliably.
[0036]
In the invention corresponding to claim 2 , since both the fiber member and the matrix member are mainly composed of SiC, the action of the substrate of claim 1 can be easily and reliably achieved.
[0037]
Furthermore, in addition to the action corresponding to claim 1 or claim 2 , the invention corresponding to claim 3 forms an oxidation-resistant coating layer on the surface of the base material, so that oxygen can be prevented from entering the base material. A self-healing type high temperature member capable of reducing the oxidation rate can be manufactured.
[0038]
In the invention corresponding to claim 4 , since the oxidation-resistant coating layer on the surface of the base material is made of Al ₂ O ₃ , the action corresponding to claim 3 can be achieved easily and reliably.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic view schematically showing a configuration of a self-healing type high temperature member according to the first embodiment of the present invention. This self-healing type high temperature member is a SiC fiber reinforced composite material 3 composed of a SiC fiber 1 and a SiC-Al-C matrix 2 held in the SiC fiber 1.
[0040]
The SiC fiber 1 contains ceramics and carbon as main components, and is formed by superimposing a plurality of SiC plain weave cloths that have been plain woven in advance and knitting each SiC plain weave cloth with SiC long fibers. Has been.
[0041]
The SiC-Al-C matrix 2 is a sintered body that is held in the SiC fiber 1 and contains ceramics and carbon as main components and contains Al. The SiC-Al-C matrix 2 has a structure in which the content of Al on the surface is higher than the content of Al in the interior, and maintains high high-temperature strength inside. It is preferable from the viewpoint of providing a chemical property.
[0042]
The SiC fiber reinforced composite material 3 is obtained by integrally forming the SiC fiber 1 and the SiC-Al-C matrix 2.
Next, the manufacturing method and operation of the self-healing type high temperature member configured as described above will be described.
(Production method)
As shown in FIG. 2, first, SiC-based plain weave cloth 4 is knitted with SiC-based long fibers 5 to form SiC-based fibers 1 (hereinafter also referred to as “preform 6”) having a desired shape (ST1; Reform process).
[0043]
Next, the gap between the preforms 6 made of the SiC fibers 1 is filled with an SiC-C slurry 7 in which fine powders of SiC and C are mixed in water or an organic solvent (ST2; impregnation step).
[0044]
At this time, if CIP (cold isotropic pressurization) 8 method using gas or water as a pressure medium is used and the pressure is set to about 196 MPa, the SiC-C-based slurry 7 is made into the gap inside the preform 7. Can be impregnated.
[0045]
Next, the preform 6 impregnated with the SiC-C-based slurry 7 is sintered while filling the melted Si-Al solution 9 to form the Si-Al-C-based matrix 2 (ST3; Reaction sintering process).
[0046]
Thereby, the SiC fiber reinforced composite material 3 composed of the SiC fiber 1 and the Si—Al—C matrix 2 is completed. In addition, it is desirable that the reaction sintering process is performed in an atmosphere of pressurized inert gas such as Ar of 49 MPa or more from the viewpoint of preventing evaporation of Al having a high vapor pressure.
[0047]
Further, the completed SiC fiber reinforced composite material 3 is machine-finished to a predetermined size in order to be applied to a base material such as a moving blade, a stationary blade, a combustor, and a shroud (ST4; machining step).
(Function)
When the SiC fiber reinforced composite material 3 is exposed to a high-temperature oxidizing atmosphere, as shown in FIG. 3A, Al in the Si—Al—C matrix 2 has a low free energy for formation of oxides, so that it is preferential. As a result, the Al-based oxide 10 such as Al ₂ O ₃ is formed on the surface.
[0048]
This Al-based oxide 10 is very dense, and since the diffusion rate of oxygen therein is slow, the oxidation rate can be reduced. However, since the Al-based oxide 10 is brittle, cracks 11 are likely to occur due to thermal shock during heating and cooling, thermal stress due to a difference in linear expansion between the SiC fiber reinforced composite material 3 and the Al-based oxide 10, and the like. .
[0049]
Next, as shown in FIG. 3B, it is assumed that the Al-based oxide 10 has cracks 11 and the SiC fiber reinforced composite material 3 is exposed.
At this time, as shown in FIG. 3C, Al in the Si—Al—C matrix 2 reacts with oxygen in the atmosphere to form an Al ₂ O ₃ Al oxide (repair) 12, The surface of the SiC fiber reinforced composite material 3 is repaired again with the Al-based oxide 12 by the self-healing action of closing the crack 11.
(Evaluation)
FIG. 4 is a view showing an increase in oxidation of the SiC fiber reinforced composite material 3 in the present embodiment at 1300 ° C. and atmospheric pressure in comparison with a conventional material. The conventional material is a SiC-C matrix (not including Al).
[0050]
As shown in the drawing, in the SiC fiber reinforced composite material 3 of the present embodiment, Al is contained in the SiC-Al-C matrix 2 and the Al oxide 10 is formed on the surface when used in a high temperature oxidizing atmosphere. As a result, the increase in oxidation could be remarkably reduced as compared with the conventional material. That is, the SiC fiber reinforced composite material 3 according to the present embodiment can remarkably improve the oxidation resistance.
[0051]
FIG. 5 is a diagram showing a change in bending strength with respect to the exposure time of the SiC fiber reinforced composite material 3 in the present embodiment to a high-temperature oxidizing atmosphere as compared with a conventional material. As shown in the figure, the SiC fiber reinforced composite material 3 of the present embodiment did not substantially decrease the bending strength even after the exposure time had elapsed, and was able to clearly improve the strength characteristics over time. On the other hand, the conventional structure has decreased the bending strength with the exposure time.
[0052]
As described above, according to the first embodiment, even when cracks 11 are generated in the Al-based oxide 10 formed on the surface of the SiC fiber-reinforced composite material 3 and the SiC fiber-reinforced composite material 3 is exposed, the Al-based material is exposed. Since it has a self-repairing function for repairing the crack 11 by re-forming the oxide 11, it is possible to achieve both mechanical strength and oxidation resistance.
[0053]
Further, by improving the oxidation resistance, that is, by suppressing the oxidation in the SiC fiber reinforced composite material 3, it is possible to reduce the breakage due to the increase in stress accompanying the oxidation thinning. In addition, the effect of suppressing the oxidative thinning becomes more remarkable in the SiC-Al-C matrix 2 in the structure in which the Al content on the surface is higher than the Al content in the interior.
[0054]
Since the SiC fiber reinforced composite material 3 has a configuration in which the SiC-Al-C matrix 2 is held in the SiC fiber 1, it can be expected to improve mechanical strength and toughness.
[0055]
In addition, the SiC fiber reinforced composite material 3 constitutes a base material for high-temperature parts such as moving blades, stationary blades, combustors, and shrouds in aircraft or power generation gas turbines, thereby improving the reliability of these high-temperature members. Can be made.
(Second Embodiment)
FIG. 6 is a schematic view schematically showing the structure of a self-repairing type high temperature member according to the second embodiment of the present invention. The same parts as those in FIG. Only the different parts will be described here.
[0056]
That is, the present embodiment is a modification in which the surface of the SiC fiber reinforced composite material 3 is coated. Specifically, as shown in FIG. 6, the SiC fiber 1 and the SiC-Al-C matrix 2 An Al ₂ O ₃ coating layer 13 having excellent oxidation resistance is formed on the surface of the SiC fiber reinforced composite material 3 made of the material.
[0057]
Here, the Al ₂ O ₃ coating layer 13 has a melting point of 2000 ° C. or higher and is scientifically stable. The surface coating layer is not limited to Al ₂ O _3, but also BeO, CeO ₂ , Cr ₂ O ₃ , HfO ₂ , La ₂ O ₃ , MgO, ThO ₂ , UO ₂ , Y ₂ O _3. And a material having a melting point of 2000 ° C. or higher that is formed from one or more oxides selected from the group consisting of ZrO ₂ can be used as appropriate.
[0058]
Next, the manufacturing method and operation of such a self-repairing type high temperature member will be described.
(Production method)
As shown in FIG. 7, the process up to the machining step ST4 is the same as the manufacturing method of the SiC fiber reinforced composite material 3 in the first embodiment.
[0059]
After the completion of the machining process ST4, the Al ₂ O ₃ coating layer 13 is formed on the surface of the SiC fiber reinforced composite material 3 by the CVD method. (ST5: CVD coating process). Specifically, the Al ₂ O ₃ coating layer 13 is formed by supplying HCl (g) and CO ₂ (g) during the growth by the CVD method. The gas reaction equations are as shown in the following equations (1) to (3).
2Al (s) + 6HCl (g)
→ 2AlCl ₃ (g) + 3H ₂ (g) (1)
3H ₂ (g) + CO ₂ (g)
→ 3H ₂ O (g) + 3CO (g) (2)
2AlCl ₃ (g) + 3H ₂ O (g)
→ Al ₂ O ₃ (s) + 6HCl (g) (3)
(Function)
The SiC fiber reinforced composite material 3 on which the Al ₂ O ₃ coating layer 13 is formed has excellent oxidation resistance and a low Al ₂ O ₃ coating layer 13 because the diffusion rate of oxygen in the Al ₂ O ₃ is slow. In the case where the SiC fiber reinforced composite material 3 is exposed due to cracking, it is repaired again with the Al-based oxide by the self-healing action as described above.
[0060]
That is, in the exposed portion due to cracking, Al in the SiC-Al-C matrix 2 reacts with oxygen in the atmosphere to form Al-based oxide (Al ₂ O ₃ ), and the crack is quickly closed.
[0061]
As described above, according to the second embodiment, since the oxidation-resistant Al ₂ O ₃ coating layer 13 is formed on the surface of the SiC fiber-reinforced composite material 3, in addition to the effects of the first embodiment, SiC Infiltration of oxygen into the fiber reinforced composite material 3 can be suppressed, and the oxidation rate can be reduced.
[0062]
Further, when the Al ₂ O ₃ coating layer 13 is cracked and the SiC fiber reinforced composite material 3 is exposed, Al in the SiC fiber reinforced composite material 3 preferentially reacts with oxygen as described above. Since the Al-based oxide is formed, rapid oxidation from the exposed portion of the SiC fiber reinforced composite material 3 due to cracking can be prevented.
[0063]
In particular, since the oxidation-resistant coating layer on the surface of the SiC fiber reinforced composite material 3 is made of Al ₂ O ₃ , these effects can be easily and reliably achieved.
(Other embodiments)
In the first embodiment, the manufacturing method of impregnation of SiC-C-based slurry, filling of Si-Al solution, and sintering has been described. However, the present invention is not limited thereto, and at least ceramic or carbon is contained as a main component. Solid solution or finely disperse the powder to be prepared and powder containing at least one of Al or an Al compound by a mechanical alloy method, and then form and sinter the powder to form a solid solution of Al in the matrix 2 Alternatively, as a manufacturing method for forming an Al compound, the present invention can be similarly performed to obtain the same effect.
[0064]
Similarly, in the matrix 2 by a sintering method, a reactive sintering method, a physical vapor deposition method, a gas phase synthesis method, a plasma spraying method, a dipping method, an electroplating method, an ion implantation method, or a combination of these methods. The same effect can be obtained by implementing the present invention in the same manner as a manufacturing method in which Al is dissolved or an Al compound is formed.
[0065]
In each of the above embodiments, both the fiber member and the matrix member have a structure containing ceramics and carbon as main components. However, the present invention is not limited to this, and it is sufficient that at least ceramics or carbon is contained in the main components. .
[0066]
Moreover, in the said 1st Embodiment, although the manufacturing method including the manufacturing process which carries out solid solution of Al was demonstrated, even if it is a manufacturing method including the manufacturing process which disperse | distributes an Al compound, it is in a base material. Since it can be substituted as a production method for containing Al element in Al, it is included in the concept of the present invention.
In addition, the present invention can be implemented with various modifications without departing from the gist thereof.
[0067]
As described above, according to the present invention, self-healing repairs cracking with an Al-based oxide even when the oxide layer or oxidation-resistant coating layer formed on the substrate surface is cracked and the substrate is exposed. It is possible to provide a method for producing a self-repairing type high-temperature member having a function and capable of achieving both mechanical strength and oxidation resistance.
[Brief description of the drawings]
FIG. 1 is a schematic diagram schematically showing a configuration of a self-repairing high temperature member according to a first embodiment of the present invention. FIG. 2 is a manufacturing process diagram in the same embodiment. FIG. 4 is a schematic diagram for explaining the self-healing function. FIG. 4 is a diagram showing the amount of increase in oxidation of the SiC fiber-reinforced composite material in the same embodiment at high temperature and atmospheric pressure in comparison with the conventional material. The figure which shows the change of the bending strength with respect to the exposure time to the high temperature oxidation atmosphere of the SiC fiber reinforced composite material in a form compared with a conventional material. FIG. 6 shows the self-repairing type high temperature member according to the second embodiment of the present invention. Schematic diagram schematically showing the configuration [FIG. 7] Manufacturing process diagram in the same embodiment [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... SiC type fiber 2 ... SiC-Al-C type matrix 3 ... SiC fiber reinforced composite material 4 ... SiC type plain weave cloth 5 ... SiC type long fiber 6 ... Preform 7 ... SiC-C type slurry 8 ... CIP
9 ... Si-Al solution 10, 12 ... Al-based oxide 11 ... crack 13 ... Al ₂ O ₃ coating layer

Claims (4)

A fiber member forming step of forming a fiber member by weaving a plurality of fibers containing at least ceramics or carbon as a main component;
An impregnation step of impregnating the fiber member with a slurry containing at least ceramics or carbon as a main component;
A matrix member forming step of forming a matrix member in the fiber member by dispersing Al or an Al compound in the fiber member impregnated with the slurry, and sintering the slurry and Al together with the fiber member. A method for producing a self-healing type member for high temperature, wherein In the manufacturing method of the member for self-healing type high temperature according to claim 1 ,
The fiber member and the matrix member both have SiC as a main component, and a method for producing a self-healing type high temperature member. In the manufacturing method of the member for self-repair type | mold high temperature of Claim 1 or Claim 2 ,
After the formation of the matrix member, a forming step of forming the base member made of the fiber member and the matrix member into a predetermined dimension by machining,
And a coating layer forming step of forming an oxidation-resistant coating layer on the surface of the molded base material by a CVD method. In the manufacturing method of the member for self-healing type high temperature according to claim 3 ,
The CVD method uses, as a raw material for the oxidation-resistant coating layer, an Al chloride gas generated by a reaction between supplied HCl gas and Al in the matrix member.
The method for producing a self-repairing type high-temperature member, wherein the oxidation-resistant coating layer is Al ₂ O ₃ .

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