JPH03199175A - Method for fitting ceramics - Google Patents

Abstract

PURPOSE:To fit ceramics to other ceramics or a metal with superior heat resistance and superior function to buffer mechanical impact, vibration and tensile stress due to the difference in coefft. of thermal expansion by placing an interposer obtd. by superposing a ceramic sheet on a metal sheet at the interface for joining. CONSTITUTION:When ceramics is fitted to other ceramics or a metal, an interposer obtd. by superposing a ceramic sheet on a metal sheet is placed at the interface for joining. Tensile stress due to the difference in coefft. of thermal expansion produced at the interface can be absorbed by allowing the ceramic sheet of the interposer to act as a gradient material. Superior heat resistance at high temp. is ensured and use even in a high-speed flow of gas is enabled.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for fitting ceramics together, particularly for fitting fine ceramics together for high-temperature structures, or for example in gas turbine dynamics. The present invention relates to a method of fitting ceramics when fitting fine ceramics for high-temperature structures and metals, such as when forming blades.

(Conventional technology) Silicon carbide, silicon nitride, aluminum nitride, sialon,
Ceramics for high-temperature structures, such as zirconia and alumina, require extremely advanced performance such as high-temperature strength properties and high-temperature fatigue properties, so it is extremely difficult to make large ones, and it is difficult to make small ones. It is common practice to make things, fit them together, and use them. Furthermore, in order to put ceramics for high-temperature structures into practical use as various products, it has become necessary to fit ceramics and metals.

The performance required when fitting ceramics for high-temperature structures is that the mating parts have excellent heat resistance and high-temperature fatigue properties, as well as mechanical impact force, vibration, and tensile strength due to differences in thermal expansion. For example, it has excellent stress buffering performance.

Conventionally, various methods have been studied for fitting ceramics together or fitting ceramics and metals as outlined above.

For example, when fitting ceramics together, as shown in FIG.
a are provided respectively, and both 1 and 2 are connected to the concave portion 1a and the convex portion 2.
In addition, in the case of fitting a ceramic and a metal directly, as shown in FIG. It is a common practice to provide the recess 1a and the protrusion 3a, respectively, and to directly fit the recess 1a and the projection 3a.

Furthermore, the Central Research Report of the Electric Power Industry (Research Report: 282009, November 1982) states that as shown in FIG. It has been proposed that ceramic wool (ceramic fiber) 4 be interposed.

(Problem to be Solved by the Invention) However, in the case where ceramics 1 and 2 are directly fitted together as shown in Fig. 12 above, there is no problem with heat resistance since both are ceramics. However, when a mechanical impact force is applied, when vibration is applied, or when tensile stress is generated due to a difference in thermal expansion, one of the ceramics 1 may crack or chip.

In addition, in the case where ceramic 1 and metal 3 are directly fitted as shown in Fig. 13, the heat resistance of ceramic 1 is far superior to that of metal 3, so the heat resistance of the fitted part is The properties are largely influenced by the heat resistance of the metal 3. Therefore, when a heat-resistant alloy is used as the metal 3, fitting with heat resistance of about 1000° C. is possible, and there is no problem with heat resistance. However, when mechanical impact force, vibration, or tensile stress due to a difference in thermal expansion occurs, the ceramic 1 may crack or chip.

Furthermore, in the case where ceramic wool 4 is interposed as shown in FIG. 14, cracking and chipping of the ceramic 1 as described above can be prevented as much as possible;
When a fitted body with ceramic wool 4 interposed is used as it is in a moving part or a part where a high-pressure gas flow is present, the ceramic wool 4 may become powdered, shift, come off, or peel off. There is a problem in that the fitting body may lose its cushioning function.

In view of the above, the present invention provides a method for fitting ceramics in which the fitting portion has excellent heat resistance and high-temperature fatigue properties, and is excellent in buffering mechanical impact force, vibration, and tensile stress caused by thermal expansion difference. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the method for fitting ceramics according to the present invention is such that when fitting ceramics to each other or ceramics and metal, a ceramic plate and a metal plate are overlapped at the bonding interface. A layer of ceramic tape made of long ceramic fibers, a ceramic sphere held in a concave groove continuously provided on at least one of the bonding interfaces, or a coating layer of composite ceramics may be interposed. This is what I did.

(Function) According to the present invention configured as described above, the tensile stress due to the difference in coefficient of thermal expansion that occurs at the bonding interface between ceramics or between ceramics and metal is applied to the ceramic plate of the intervening material. By acting as a material, by the flexibility of the ceramic long fibers that make up the layer of the ceramic tape interposed here, by the rolling of ceramic spheres interposed here, or by the intervening here. The slip caused by the low coefficient of friction of the composite ceramic coating layer can be absorbed by each layer, and it also has excellent heat resistance at high temperatures, making it possible to use it even in a high-speed gas flow atmosphere.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a first embodiment of the present invention which is adapted to manufacture a hybrid-type gas turbine g10 consisting of a ceramic blade body 11 and a metal body 12 having excellent heat resistance such as Inconel. This shows an example, and in this hybrid rotor blade 10, a metal lid body 13 having a convex portion 13a at the center of the blade is fitted into the open end of the hollow ceramic blade body 12. .

When fitting the metal lid body 13, there is a gap between the interface between the ceramic wing body 11 and the metal lid body 13, that is, the end surface of the ceramic blade body 11 and the periphery of the convex portion 13a of the metal lid body 13. A ring-shaped interposition 14 is interposed, which is constructed by joining a metal plate 14a and a ceramic plate 14b at a joint 14c.

This interposition 14 is made of, for example, metal nickel (Ni
) and silicon nitride ceramics using an active metal method.

The ceramic plate 14a of this interposition 14 has a coefficient of thermal expansion approximately intermediate between that of the ceramic wing body 11 and the metal lid body 13, and serves as a gradient material, and the metal plate 14b A material with a low elastic modulus is used to fulfill the role of a cushioning material. Thereby, stress caused by mechanical impact force and thermal expansion can be alleviated.

Furthermore, it goes without saying that the ceramic plate 14a of the interposition 14 may be made of zirconia, which has a high heat insulating property.

FIG. 3 shows a disc-shaped interposition 14' formed by joining a disc-shaped ceramic plate 14a' and a disc-shaped metal plate 14b' to each other at a joint 140', and this interposition 14′,
It is arranged at the interface between the convex part 2a of the ceramic 2 and the concave part 5a of the metal 5, which can fit into each other.

In addition, as shown in FIG. 4, an intervening member 14' is formed by separating the ceramic 14a'' and the metal 14b' without joining them, so that the ceramics 14a'' and the metal 14b' come into pressure contact with each other when they are fitted. You can also do this.

FIG. 5 shows a second embodiment, which differs from the first embodiment shown in FIGS. 1 and 2 above in fitting the ceramic wing body 11 and the metal lid body 13. A layer of ceramic tape made of long ceramic fibers is provided at the interface between the ceramic wing body 11 and the metal lid body 13, that is, between the end face of the ceramic wing body 11 and the periphery of the convex portion 13a of the metal lid body 13. 15 and a zirconia plate 16 for heat insulation.

The above-mentioned ceramic tape is made by processing a yarn made of several thousand water bundles of fibers of about 10 μm, for example, into a tape shape without reinforcing other fibers, such as cloth or sleeve. Each end is specially treated to prevent it from unraveling.

In this way, the ceramic wing body 11 and the metal lid body 13
By providing the ceramic tape layer 15 made of ceramic long fibers at the interface with the ceramic tape layer 15, the ceramic long fibers constituting the ceramic tape layer 15 can be easily deformed. Ceramic tape buffers stress and also has excellent corrosion resistance, so it can be used in special environments.

In the above embodiment, the ceramic tape layer 15 is formed by directly pasting the ceramic tape on the interface between the ceramic wing body 11 and the metal lid body 13. It is also possible to use a ceramic tape layer formed by wrapping a ceramic tape around it.

FIG. 6 shows a third embodiment, and the difference from the embodiment shown in FIGS. 1 and 2 above is that the ceramic wing body 1
1 and the metal lid body 13, the interface between the ceramic wing body 11 and the metal lid body 13, that is, between the end surface of the ceramic blade body 11 and the periphery of the convex portion 13a of the metal lid body 13. For example, a ceramic ball 17 is interposed in a concave portion 13b continuously formed in an annular shape on the side of the metal lid 13 and held in such a manner that it cannot escape.

As a result, mechanical shock, vibration, and tensile stress caused by a difference in coefficient of thermal expansion are alleviated by the displacement and bending of the concave portion 13b provided in the metal lid 13. At this time, the ceramic sphere 17 is Move so as to smoothly perform the displacement and bending of 13.

Therefore, the fit is extremely excellent in heat resistance and has an excellent function of buffering mechanical impact force, vibration, and tensile stress caused by differences in thermal expansion coefficients.

Incidentally, it goes without saying that the grooved portion 13b may be provided on the side of the ceramic wing body 11, and the ceramic ball 17 is made of, for example, silicon carbide and has a stable operating temperature of 150°C.
It is at 0°C.

FIG. 7 shows a fourth embodiment, and the difference from the embodiment shown in FIGS. 1 and 2 above is that the ceramic wing body 1
1 and the metal lid body 13, the interface between the ceramic wing body 11 and the metal lid body 13, that is, between the end surface of the ceramic blade body 11 and the periphery of the convex portion 13a of the metal lid body 13. For example, a coating layer 18 made of a composite ceramic based on chromium oxide is provided on the metal lid 13 side, and a zirconia plate 16 is further interposed for heat insulation.

Here, the coating layer 18 of composite ceramics has high wear resistance, so it is suitable for high-speed sliding and can be used even at high temperatures. Furthermore, since the coating layer 18 has excellent impact resistance and corrosion resistance, it can be used in special environments.

As shown in FIG. 8, when fitting the convex part 2a of the ceramic 2 into the concave part 5a of the metal 5, a coating layer 18 of composite ceramics is applied to the inner surface of the concave part 5a of the metal 5.
A plate 16 is interposed as necessary. At this time, as shown in FIG. 9, the metal 5 is composed of two members 5b and 5c, and the surface of one metal 5C is coated. After applying the coating layer 18 by polishing the coating layer 18 to a uniform thickness, the two members 5b and 5c were connected by screws (not shown) to provide the coating layer 18 of composite ceramics. Metal 5 can be obtained.

In addition, in the case of fitting ceramics together, it is desirable to interpose a metal with a coating layer on both contact surfaces with the ceramics.Furthermore, when used at extremely high temperatures, as mentioned above, for example, as a heat insulating material, A zirconia plate 16 can be used to address this.

The results of a thermal cycle test of tensile stress due to the difference in coefficient of thermal expansion using the fitted bodies constructed according to each of the above embodiments and the conventional examples shown in FIGS. 13 and 14 are shown below. It is shown in Figure 10.

As shown in FIG. 11, the test machine at this time had a heater 20 placed in a test chamber having a high-speed gas inlet 19a and a high-speed gas outlet 19b, and the test equipment was placed on top of this heater 20. A test piece A was placed on the test piece A, and a metal water-cooled compression jig 21 was placed on top of the test piece A.

Then, a cycle of heating-cooling-heating was repeated until the temperature reached 1300° C. under a high-speed gas flow atmosphere while applying a load of 1600 kgf.

Here, test piece A is a fitted body in which a ceramic 2 and a metal 5 (see FIGS. 3 and 8) are fitted together; (2) The structure according to the third embodiment (2) The structure according to the third embodiment (4) The ceramic 2 and the metal 5 shown in FIG. 13 are directly fitted together. (2) Ceramic wool 4 is interposed between the ceramic 2 and metal 5 shown in FIG. 14 above, respectively.

As is clear from this experimental result, in the test piece (2) in which the ceramic 2 and the metal 5 were in direct contact, the tensile stress due to the difference in thermal expansion coefficient generated at the interface between the ceramic 2 and the metal 5 could not be absorbed. Ceramic 2 will immediately chip and crack.

In addition, in the test piece (2) with the ceramic wool 4 interposed, the tensile stress due to the difference in thermal expansion coefficient can be absorbed initially, but the ceramic wool 4 may become powdered, shift, come off, or It may peel off and gradually become unable to be absorbed, causing the ceramic 1 to chip or crack.

On the other hand, in the test piece (2) constructed according to the first embodiment, the deformation of the metal 4 and the mating portion of the ceramic plate and the metal plate function like an inclined member, so that the ceramic plate 2 and the metal plate function like inclined members. The tensile stress caused by the difference in thermal expansion coefficient generated at the interface of the metal 5 is absorbed by the above portion, and furthermore, it can be used even in a high-speed gas flow atmosphere.

In the test piece ■ constructed according to the second embodiment,
The tensile stress caused by the difference in coefficient of thermal expansion generated at the interface between the ceramic 2 and the metal 5 is absorbed by the flexibility of the ceramic long fibers constituting the ceramic tape. Moreover, it has excellent heat resistance at high temperatures, and its high elastic modulus not only allows it to withstand mechanical impact and vibration.
It can be used even in high-speed gas flow atmospheres.

In the test piece ■ constructed according to the third embodiment,
The tensile stress caused by the difference in thermal expansion coefficient generated at the interface between the ceramic 2 and the metal 5 is absorbed by the slippage caused by the low coefficient of friction of the coating layer, and furthermore, it can be used even in a high-temperature gas flow atmosphere.

In the test piece ■ constructed according to the fourth embodiment,
The tensile stress due to the difference in thermal expansion coefficient generated at the interface between the ceramic 2 and the metal 5 is absorbed by the rolling of the ceramic sphere held in the recess of the metal 5, and furthermore, it can be used even in a high-pressure gas flow atmosphere.

〔Effect of the invention〕

Since the present invention has the above-described structure, it is possible to provide a method for purchasing ceramics that has extremely high heat resistance and has an excellent function of buffering mechanical impact force, vibration, and tensile stress caused by differences in thermal expansion coefficients. There is an effect like this.

[Brief explanation of drawings]

1 and 2 show a fitted body (turbine rotor blade) constructed using the first embodiment of the present invention, and FIG. 1 is a longitudinal sectional view (a sectional view taken along the line I-I in FIG. 2). , Figure 2 is a perspective view, Figure 3 is a perspective view.
The figure is a sectional view showing a modified example, FIG. 4 is a sectional view showing another embodiment of the insert, and FIGS. 5 to 7 are views corresponding to FIG. Figures 8 and 9 are cross-sectional views showing modified examples of holes using coating layers, Figure 10 is a graph showing the results of a thermal cycle test of tensile stress due to the difference in thermal expansion coefficient, and Figure 11 is a graph showing the results of this thermal cycle. A schematic diagram of the apparatus used in the test, and FIGS. 12 to 14 are cross-sectional views showing conventional examples with holes, respectively. 1.2...ceramics, 3,5...metal, 10.
... Hybrid rotor blade, 11 ... Ceramic blade body, 12 ... Metal main body, 13 ... Metal lid body, 1
3b... Concave portion, 14... Interposition, 14a... Metal plate, 14b... Ceramic plate, 15... Ceramic tape layer, 16... Plate, 17... Ceramic Sphere, 18... coating layer.

Claims (1)

[Scope of Claims] 1. Fitting of ceramics, characterized in that when fitting ceramics to each other or ceramics to metal, an interposition consisting of a ceramic plate and a metal plate is interposed at the bonding interface. Method. 2. A method for fitting ceramics, which comprises interposing a layer of ceramic tape made of long ceramic fibers at the bonding interface when fitting ceramics to each other or ceramics to metal. 3. A method for fitting ceramics, which comprises interposing a ceramic ball held in a concave groove continuously provided on at least one of the bonding interfaces when fitting ceramics together or ceramics and metals. . 4. A method for fitting ceramics, which comprises interposing a coating layer of composite ceramics at the bonding interface when fitting ceramics to each other or ceramics to metal.