JP2002285801A - Combination member and part for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine rotor comprising: a combination member excellent in mechanical reliability and heat resistance; a turbine that prevents mating members to be damaged with each other even if the members contact- slide by narrowing a gap between the members in order to improve thermal efficiency; and a turbine shroud. SOLUTION: In the combination member composed of a rotating member 1 formed of ceramic and a ceramic member 2 situated in the vicinity of the rotating member 1, the hardness of the rotating member 1 is 13-16 GPa, the hardness of the ceramic member 2 is 5-10 GPa, the porosity of the rotating member 1 and the ceramic member 2 is 5% or less, and a minimum gap 3 between the rotating member 1 and the ceramic member 2 is 1 mm or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination member, and more particularly, to a turbine which is a rotating member in a gas turbine, a jet engine, etc., and has improved lightening and oxidation resistance and improved grinding performance. The present invention relates to a gas turbine component which is used for a stationary member such as a turbine shroud facing a tip of a turbine blade, is excellent in economy, and has high efficiency.

[0002]

2. Description of the Related Art Recently, high-temperature combustion of gas turbines has been progressing with high efficiency. For this reason, the temperature around the combustion chamber is increasing, and its heat resistance is becoming important. In particular, a turbine rotor, which is a rotating component as its central member, and a shroud, which is a stationary component as its casing, are used in combination, and are required to have high strength and heat resistance, as well as high sealing properties to prevent leakage of working gas. ing.

For this reason, ceramics such as silicon nitride, aluminum titanate, cordierite and the like have been conventionally used for engine parts. However, oxides such as aluminum titanate and cordierite are difficult to obtain a dense body, and have low room temperature strength of about 40 MPa, and further lower strength at high temperatures. There was a problem that was difficult.

Further, a silicon nitride sintered body is preferable as a turbine rotor because of its high strength, high toughness and excellent mechanical properties. However, when used for a stationary member, specifically, a turbine shroud, the rotation of the turbine rotor can be reduced. During this, there is a problem that the rotor tip and the shroud come into contact and slide, and at that time, the turbine rotor and the shroud are broken. Conversely, if a gap is provided widely to avoid contact, there is a problem that the working gas leaks and the thermal efficiency decreases.

Therefore, it is disclosed in Japanese Patent Application Laid-Open No. H11-110702 that a ceramic part having a high porosity and a low hardness is used for the shroud so that the tip of the turbine is worn out while being in contact with the shroud, thereby reducing the gap and improving the sealing performance.
It has been proposed in JP-A-310465.

[0006]

However, in the method described in Japanese Patent Application Laid-Open No. H11-310465, the porosity is increased to 10% or more in order to reduce the hardness, so that the strength is low, and the porosity is damaged at the time of contact. There was a problem that it was easy.

Further, since the porosity is large, the reaction surface area with oxygen gas becomes large, so that the oxidation reaction easily proceeds.
There has been a problem that the silicon nitride member has a large increase in oxidation and is inferior in oxidation resistance.

Accordingly, the present invention provides a combined member having excellent mechanical reliability and heat resistance, and a narrow gap between the members in order to enhance thermal efficiency. It is an object of the present invention to provide a gas turbine component including a combination member, a method for manufacturing the same, and a turbine and a turbine shroud.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a minimum gap of 1 mm or less is obtained by combining a member made of ceramics having different hardnesses and removing a part of the ceramic having a low hardness by rotating the rotating member. Based on the finding that a combination member having the following characteristics can be realized, as a result, the reliability of the combination member can be prevented by improving the reliability thereof, and the sealing property can be improved because the gap between the members is small. In particular, it has been found that a combination of a dense silicon nitride-based sintered body and a cordierite-based sintered body is preferable, and can be optimally used as a gas turbine component.

That is, a combined member according to the present invention is a combined member comprising a rotating member made of ceramics and a ceramic member provided close to the rotating member, wherein the hardness of the rotating member is 13 to 16 GPa, The hardness of the member is 5 to 10 GPa, the porosity of the rotating member and the ceramic member is 5% or less, and the minimum gap between the rotating member and the ceramic member is 1 mm or less.

By setting the hardness of the dense rotating member and the hardness of the ceramic member to the above values, although the ceramic member having a low hardness is worn, the damage of the combination member can be prevented, and the mechanical reliability is improved. be able to. Also, the minimum gap between the rotating member and the ceramic member is 1
mm or less, the sealing performance can be improved.

Preferably, the thermal expansion coefficient of the rotating member is larger than the thermal expansion coefficient of the ceramic member, whereby the gap can be narrowed and the thermal efficiency can be improved.

Further, it is preferable that the hardness difference between the rotating member and the ceramic member is 4 to 10 GPa. Thereby, the mechanical reliability can be further improved, and the sealing performance can be improved.

Further, it is preferable that the rotating member is made of a silicon nitride sintered body and the ceramic member is made of a cordierite sintered body. As a result, the reliability of the rotating body that requires high strength as the rotating body can be improved, the gap can be reduced because the coefficient of thermal expansion of the ceramic member is low, and the hardness is low. Nothing to do.

Further, it is preferable that the cordierite-based sintered body contains a rare earth oxide in a ratio of 0.5 to 20% by weight. This makes it possible to densify cordierite, for which it is difficult to obtain dense properties, and to improve heat resistance, oxidation resistance, and corrosion resistance.

Further, the cordierite-based sintered body of
The strength at 00 ° C. is preferably 80 MPa or more. Thereby, the reliability as a gas turbine component can be improved.

Further, the cordierite-based sintered body preferably contains at least one of silicon nitride, silicon carbide and silicon oxynitride in a proportion of 40% by weight or less. Thereby, strength can be improved and reliability can be improved.

Further, the method for manufacturing a combination member according to the present invention comprises:
At least a part of the ceramic member having a porosity of 5% or less and a hardness of 5 to 10 GPa is provided with a porosity of 5% or less and a hardness of 13 to 16
A rotating member made of GPa ceramics is arranged, and the rotating member is rotated to remove at least a part of the ceramic member by contact abrasion, and a minimum gap between the ceramic member and the rotating member is 1 mm or less. Accordingly, the combined member of the present invention with improved oxidation resistance and sealing properties can be realized.

In particular, it is preferable that the ceramic member and the rotating member are brought into contact and abrasion while being heated to 800 to 1500 ° C. As a result, the reliability and sealability at high temperatures can be further improved.

Further, the gas turbine component according to the present invention includes:
In a component for a gas turbine including a turbine rotor and a turbine shroud, the combination member is used as the turbine rotor and the turbine shroud, whereby high-temperature combustion is possible,
A working gas leak is reduced, a mechanical reliability is high, and a gas turbine system with high thermal efficiency can be realized.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A combination member according to the present invention comprises, as shown in FIG.
A ceramic member 2 is provided near the rotating member 1, and a gap 3 is provided between the rotating member 1 and the ceramic member 2. In addition, the ceramic member 2
It may be stationary or rotating.

According to the present invention, the rotating member 1 has a hardness of 13
It is important to be made of ceramics of up to 16 GPa. If the hardness is less than 13 GPa, it is difficult to efficiently remove a part of the ceramic member 2 due to abrasion, and the ceramic member 2 is likely to be damaged due to contact during rotation. If it is larger than 16 GPa, the ceramic member 2 is likely to be damaged, and the manufacturing cost is increased.

The hardness of the ceramic member 2 is 5-10.
It is also important to be GPa. If it is less than 5 GPa, wear due to minute substances mixed into the airflow becomes remarkable, and if it is more than 10 GPa, it is difficult to remove by abrasion, and one of them is broken by contact with the rotating member 1.

If the rotating member 1 and the ceramic member 2 have the above-mentioned combination of hardness, a part of the ceramic member 2 is removed by abrasion due to the contact at the time of rotation, and damage can be prevented. To make this effect more effective,
In order to realize a smaller member gap, the hardness of the rotating member 1 is preferably 14 to 15 GPa.
Is preferably 7 to 9 GPa.

In particular, the hardness of the rotating member 1 is 13 to 16 GP
a, In addition to the hardness of the ceramic member 2 being 5 to 10 GPa, the hardness difference between the rotating member 1 and the ceramic member 2 is preferably 4 to 10 GPa, particularly preferably 5 to 8 GPa. Due to this hardness difference, the rotating member 1
Can be efficiently removed by abrasion, and the reliability by destruction prevention can be further enhanced.

It is important that the porosity of both the rotating member 1 and the ceramic member 2 be 5% or less. Thereby, the reaction surface area with the oxidizing gas or the oxygen in the air can be reduced, and the oxidation increase of the rotating member 1 and the ceramic member 2 can be reduced. Can be increased. In particular,
The porosity of the rotating member 1 and the ceramic member 2 is particularly 3%.
Below, 1% or less is preferable in order to further improve mechanical reliability and oxidation resistance.

Depending on the environment in which the rotating member 1 is used, for example, when used as a gas turbine component, the rotating member 1 has high toughness, light weight, high strength at room temperature and high temperature, and excellent oxidation resistance. It is preferable to be made of ceramics such as silicon nitride, silicon oxynitride, silicon carbide, mullite, zirconia, etc., and a composite material containing ceramics selected from these groups.

Further, according to the present invention, the minimum gap 3 among the gaps 3 between the rotating member 1 and the ceramic member 2 is 1 mm.
It is important that: By reducing the minimum gap 3, the sealing performance can be improved. For example, in a gas turbine, the efficiency can be improved by reducing the gap between the turbine rotor and the turbine shroud.

In the present invention, the hardness of the rotating member 1 is 13 to 1
6 GPa, the hardness of the ceramic member 2 is 5 to 10 GPa, and the gap 3 is provided in advance by abrasion.
A small gap 3 of 1 mm or less can be maintained. For example, even if these members come into contact with each other, the ceramic member 2 is removed by abrasion, so that the rotation member 1 and the ceramic member 2 can be prevented from being damaged.

The gap 3 between the rotating member 1 and the ceramic member 2
Can be reduced to 0.8 mm or less, especially 0.5 mm or less, in order to improve the sealing property, and the thermal efficiency can be further improved.

It is preferable that the thermal expansion coefficient of the rotating member 1 is larger than that of the ceramic member 2. Thus, for example, during operation of the gas turbine, the gap 3 can be further reduced due to a rise in temperature, and the sealing performance can be further improved.

As a combination member having the above hardness and porosity, a silicon nitride sintered body is used for the rotating member 1 and a cordierite sintered body is used for the ceramic member 2, particularly as in a gas turbine. It is preferable as a member used at an extremely high temperature.

This is because the silicon nitride sintered body has high strength and high toughness and high mechanical reliability against breakage due to rotation. The room temperature strength of this silicon nitride sintered body is 800 MPa or more,
The high-temperature strength at 000 ° C. is preferably 500 MPa or more. The silicon nitride sintered body may contain a hard substance such as silicon carbide or boron carbide in an amount of 30% by weight or less, particularly 10 to 20% by weight, in order to increase the hardness.

When the cordierite-based sintered body is used as a component used at a high temperature such as a gas turbine, the high-temperature strength at 1000 ° C. is 80 MPa or more, particularly 10 MPa.
0 MPa or more, and more preferably 150 MPa or more is preferable from the viewpoint of enhancing mechanical reliability.

A sintering aid is indispensable to obtain such a dense and high-temperature cordierite sintered body. For example, 0.5 to 20% by weight of rare earth oxide, especially 2 to 1%
It can be contained in an amount of 5% by weight, further 5 to 10% by weight. If it is less than 0.5% by weight, it is not easy to densify,
If it is 0% by weight or more, the high temperature characteristics tend to deteriorate.

Furthermore, the cordierite-based sintered body contains at least one of silicon nitride, silicon carbide and silicon oxynitride in an amount of 40% by weight or less, particularly 5 to 30% by weight, and more preferably 10 to 20% by weight. By doing so, the strength can be further increased, and the ceramic member 2 can be suitably used particularly for a gas turbine component. In order to improve the corrosion resistance of the cordierite-based sintered body, the porosity is set to 5
%, Particularly 3% or less, or even 1% or less.

Next, the method of manufacturing a combination member according to the present invention will be described by taking as an example a case where a silicon nitride sintered body is used for the rotating member 1 and a cordierite sintered body is used for the ceramic member 2.

First, a cordierite-based sintered body used for the ceramic member 2 is manufactured. As a starting material, cordierite powder having an average particle size of 5 μm or less, particularly 3 μm or less,
A rare earth oxide powder having an average particle size of 2 μm or less, and powders such as a silicon nitride powder, a silicon carbide powder, and a silicon oxynitride powder, if desired, are prepared.

The above powder was prepared by adding cordierite powder to 80
-99.5% by weight, especially 85-98% by weight, even 88
To 95% by weight, and the rare earth oxide powder is mixed in an amount of 0.5 to 20% by weight, particularly 2 to 15% by weight, and more preferably 5 to 10% by weight. If desired, at least one of silicon nitride powder, silicon carbide powder, and silicon oxynitride powder may contain up to 40% by weight of the cordierite powder, particularly 5 to 30% by weight, and more preferably 10 to 20% by weight. Substitute and mix.

After the mixed powder blended so as to satisfy the above composition is sufficiently mixed and / or pulverized by a ball mill or the like, desired molding means, for example, die press, cast molding, cold isostatic pressing, extrusion It can be formed into a desired shape by a method such as molding.

These compacts are placed in air, vacuum, or
r, in an inert gas atmosphere such as N ₂ 1200 to 1500
° C, preferably 1 to 1 in a temperature range of 1250 to 1400 ° C.
By sintering for about 10 hours, a sintered body having a porosity of 5% or less can be obtained. If the sintering temperature is lower than 1200 ° C., nitriding and densification are not sufficiently performed, and if the firing temperature is higher than 1500 ° C., the molded body is melted.

As the firing method, for example, a hot pressing method, a normal pressure firing, a nitrogen gas pressure firing, or a hot isostatic firing under a high pressure of 1000 atm or more after these firings can be used.

It is important that the cordierite-based sintered body thus produced is a ceramic member having a porosity of 5% or less and a hardness of 5 to 10 GPa.

Next, a silicon nitride sintered body used for the rotating member is manufactured. As a starting material, the total amount of metal element impurities other than silicon is 1% by weight or less, preferably 0.5% by weight or less, and the average particle size is 0.3 to 1 μm, preferably 0.5 to 1%.
A 0.8 μm silicon nitride powder is prepared. This raw material powder can be used in either α-type or β-type with an impurity oxygen content of 0.5 to 2.0% by weight. As a sintering aid, rare earth oxide powder having an average particle size of 2 μm or less A 0.8 μm alumina, silicon dioxide or the like is prepared. The total amount of the auxiliaries is preferably from 5 to 15% by weight in order to enhance high-temperature characteristics. If desired, a hard ceramic powder such as silicon carbide having an average particle diameter of 1 μm or less or boron carbide having an average particle diameter of 2 μm or less may be added. After sufficiently mixing and / or pulverizing the mixed powder with a ball mill or the like, the mixture is molded into a desired shape by a desired molding means, for example, a method such as a die press, a casting, a cold isostatic pressing, or an extrusion molding. be able to.

After degreasing these compacts, they are heated at 1600 to 1900 ° C., preferably 17 ° C. in an inert gas atmosphere such as N _2.
By sintering in a temperature range of 50 to 1850 ° C. for about 1 to 10 hours, a sintered body having a porosity of 5% or less can be obtained. If the firing temperature is lower than 1600 ° C., the nitriding and densification will not be sufficiently performed.

As the firing method, for example, a hot press method, a normal pressure firing, a nitrogen gas pressure firing, and a hot isostatic firing under a high pressure of 1000 atm or more after these firings can be used. For firing a complicated rotating body such as a turbine rotor, normal pressure firing and nitrogen gas pressure firing are preferable.

The silicon nitride sintered body used for the rotating member thus manufactured has a porosity of 5% or less and a hardness of 13 to 16 GP.
It is important that the ceramic member is a.

The above-mentioned rotating member and ceramic member are each processed into the shape shown in FIG. 1, and at least a part of the ceramic member is combined so as to be in contact with the rotating member.
That is, at least a part of the ceramic member having a porosity of 5% or less and a hardness of 5 to 10 GPa is converted to a porosity of 5% or less and a hardness of 13
It is arranged so as to be in contact with a rotating member made of ceramics of up to 16 GPa. At this time, it is preferable that the rotation axis of the rotating member and the center axis of the ceramic member are aligned, but the contact may be performed with an error of 1 mm or less for contact.

It is important to rotate the rotating member to remove at least a part of the ceramic member by contact abrasion. The rotation speed is, for example, 1 until the wear is completed.
It is preferable that the speed is as low as 0000 rpm or less, particularly 5000 rpm or less, and more preferably 3000 rpm or less. It is also important that the minimum gap between the ceramic member and the rotating member be 1 mm or less.

It is important that the minimum gap between the ceramic member and the rotating member is reduced to 1 mm or less by this process.
Thereby, the sealing performance can be improved.

[0051] Note that the hardness used in the present invention means a Vickers hardness (H _v), H _v of the sintered body can be measured by applying a load of 20 kg.

Further, the gas turbine component of the present invention
In a gas turbine component including a turbine rotor and a turbine shroud, the combination member of the present invention is the turbine rotor and the turbine shroud. An example is shown in FIG.

In this gas turbine, a turbine rotor 11 corresponding to a ceramic rotating member, and a turbine shroud 12 corresponding to a ceramic member and being a stationary component.
, But are arranged in close proximity. Turbine rotor 1
1 comprises a shaft portion 11a and a wing portion 11b,
The blade 11 b rotates in the direction of the arrow away from the turbine shroud 12 by the gap 13, and gas leaks from the gap 13.

The gas turbine using the combination member of the present invention can perform high-temperature combustion, reduce leakage of working gas,
A gas turbine system with high mechanical reliability and high thermal efficiency can be realized.

[0055]

EXAMPLE Cordierite powder having an average particle size of 2 μm;
Rare earth element oxide powder having an average particle size of 1 μm, average particle size of 0.
Using 5 μm silicon nitride powder, silicon carbide powder having an average particle size of 0.5 μm, and silicon oxynitride powder having an average particle size of 0.5 μm,
After mixing to obtain the composition shown in Table 1, the mixture was mixed with a ball mill to obtain 24
After mixing for an hour, CIP molding was performed at a pressure of 100 MPa. Then, the compact was placed in an alumina sagger, and Table 1
And a cordierite-based sintered body was produced.

Using a 95% α-silicon nitride powder having an average particle size of 0.5 μm, a yttria powder having an average particle size of 1 μm, and an alumina powder having an average particle size of 0.8 μm, the mixture was mixed in a ball mill for 24 hours. CIP at a pressure of 100 MPa
Molded. Then, the formed body was placed in a silicon carbide sagger and fired to produce a silicon nitride sintered body having the hardness shown in Table 1.

The obtained sintered body was polished and 3 × 4 × 15 m
Grinding to the size of m, room temperature of this sample, 1000 ℃
The four-point bending strength based on JISR1601 was measured.
The porosity of the obtained sintered body was measured by Archimedes' method, and the hardness was measured at room temperature under a load of 20 kg using a Vickers hardness tester.

Further, a measurement sample was cut out from the above sample, and the coefficient of thermal expansion based on JISR1618 was measured.

Next, a turbine shroud facing the turbine rotor as shown in FIG. 2 was made of various ceramic sintered bodies using the above sintered bodies. Then, by rotating the turbine rotor at 40,000 rpm, it was tested by a spin test whether or not the turbine blade was damaged. The results are shown in Tables 1 and 2.

[0060]

[Table 1]

[0061]

[Table 2]

Sample No. of the present invention 2-4, 7-10, 1
2-13, 16, 17, 19-22, 24-32, 34
As for No.-40, the result of the spin test was good. It did not break when it came into contact with the turbine.

On the other hand, No. 1 having a high porosity and a low hardness of the rotating member is out of the range of the present invention. In Nos. 1 and 6, the turbine rotor was damaged in the spin test.

In addition, the hardness of the rotating body is high and the hardness of No. In No. 5, the turbine shroud was damaged in the spin test.

Further, since the gap was as large as 2 mm, the sample No. was out of the range of the present invention. In No. 11, the leakage was large, and the efficiency of the engine was reduced.

Further, the porosity is as large as 7% or more,
In addition, the sample No. having a hardness as low as 4 GPa and outside the range of the present invention.
In Nos. 14, 15, and 18, the room temperature strength was as low as 70 MPa or less, and the turbine shroud was broken in the spin test.

The sample No. having a hardness of 4 GPa, which is out of the range of the present invention, was used. In No. 23, the turbine shroud was damaged in the spin test.

Further, the hardness of the ceramic member is 11 GP.
a and sample Nos. In No. 33, the turbine shroud was damaged in the spin test.

[0069]

According to the combined member of the present invention, the hardness of the rotating member and the ceramic member is controlled, so that the ceramic member is removed by abrasion even by contact, and a small gap is formed, so that the component is damaged by the contact. I will not let you. In particular, it can be optimally used as a stationary component for turbines and gas turbines.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the structure of a combination member of the present invention.

FIG. 2 is a sectional view showing the structure of the gas turbine component of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotating member 2 ... Ceramic member 3, 13 ... Gap 11 ... Turbine rotor 11a ... Shaft part 11b ... Blade part 12 ... Turbine shroud

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02C 7/28 C04B 35/58 102D

Claims (10)

[Claims] 1. A combined member comprising a rotating member made of ceramics and a ceramic member provided adjacent to the rotating member, wherein the hardness of the rotating member is 13 to 16G.
Pa, the hardness of the ceramic member is 5 to 10 GPa, the porosity of the rotating member and the ceramic member is 5% or less, and the minimum gap between the rotating member and the ceramic member is 1 mm or less. . 2. The combination member according to claim 1, wherein a thermal expansion coefficient of said rotating member is larger than a thermal expansion coefficient of said ceramic member. 3. The rotating member and the ceramic member have a hardness difference of 4 to 10 GPa.
Or the combination member according to 2. 4. The combination member according to claim 1, wherein said rotating member is made of a silicon nitride-based sintered body, and said ceramic member is made of a cordierite-based sintered body. 5. The combination member according to claim 4, wherein said cordierite-based sintered body contains a rare earth oxide in a ratio of 0.5 to 20% by weight. 6. The temperature of the cordierite-based sintered body is 1000 ° C.
The combined member according to claim 4, wherein the strength is 80 MPa or more. 7. The cordierite-based sintered body is silicon nitride,
7. The composition according to claim 4, wherein at least one of silicon carbide and silicon oxynitride is contained in a proportion of 40% by weight or less.
The combination member according to any one of the above. 8. At least a part of a ceramic member having a porosity of 5% or less and a hardness of 5 to 10 GPa is arranged so as to be in contact with a rotating member made of a ceramic having a porosity of 5% or less and a hardness of 13 to 16 GPa. A method for manufacturing a combination member, comprising: rotating a rotating member to remove at least a part of the ceramic member by contact abrasion, and reducing a minimum gap between the ceramic member and the rotating member to 1 mm or less. 9. The method according to claim 8, wherein the ceramic member and the rotating member are contact-weared while being heated to 800 to 1500 ° C. 10. A gas turbine component comprising a turbine rotor and a turbine shroud, wherein the turbine rotor and the turbine shroud are formed by using the combination member according to any one of claims 1 to 7. Turbine parts.