JPH11343803A - Thermal insulation member having clearance control layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal insulation member wherein the occurrence of breaking caused by peeling-off between a base material and a clearance control layer (abrasive layer) is difficult. SOLUTION: In a thermal insulation member prepared in such a manner that a clearance control layer installed to cover the outer periphery of a turbine moving blade and abraded for its surface by the outer periphery of the same to optimize a clearance with the turbine moving blade is formed in the surface of a base material 21, the base material 21 is made of a ceramic base composite material baked by further impregnating a preform made of fiber connected solid ceramic with ceramic, and by thermal spraying ceramic 22 to the surface thereof, the clearance control layer 23 made of porous ceramic is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat shield member usable as, for example, a turbine shroud of a gas turbine. (A layer for optimizing the clearance between the layers, generally called an abradability layer).

[0002]

2. Description of the Related Art FIG. 2 schematically shows a part of a gas turbine. In FIG. 2, L is a turbine axis, 1 is a turbine shroud, 2 is a turbine casing, 3 is a turbine rotor blade, 4 is a turbine vane, and the turbine shroud 1
Are arranged so as to cover the outer periphery of the turbine rotor blade (rotating body) 3. Usually, this turbine shroud 1 is formed in a ring shape by connecting a plurality of segments in a circumferential direction.

In general, the turbine shroud 1 has a turbine blade 3
A clearance control layer (abradability layer) for optimizing the clearance between the base member and the base member is formed of a heat shielding member.

In a conventional turbine shroud, as shown in FIG. 3, a porous ceramic layer (clearance control layer) 13 having an abradability effect is formed on a metal base material 11 via a bond coat layer 12 by thermal spraying. And a heat shield member.

[0005]

However, in the above-mentioned conventional heat shielding member, the linear expansion coefficients of the metal base material 11 and the ceramic layer 13 are greatly different from each other. It was likely to occur. In addition, oxygen passes through the ceramic layer 13 which has a porous shape so as to have abradability, and reaches the metal base material 11 so that the metal base material 11 may be oxidized. There was a problem that the property is low.

[0006] The present invention has been made in view of the above circumstances, it is difficult to cause destruction due to peeling between the base material and the clearance control layer, and does not cause a decrease in durability and reliability due to oxidation of the base material. It is another object of the present invention to provide a heat shielding member capable of achieving both heat shielding of a high-temperature combustion gas and an abradability function for clearance control.

[0007]

As means for solving the above-mentioned problems, a heat shielding member having the following configuration is employed. This heat shield member is installed so as to cover the outer periphery of the rotating body, and a surface is shaved by the outer periphery of the rotating body to form a clearance control layer on the surface of the base material that optimizes clearance between the rotating body and the rotating body. Wherein the base material is made of fiber-bonded three-dimensional ceramics, and the ceramics are sprayed on the surface to form the clearance control layer made of porous ceramics. It is characterized by.

The base material is preferably made of a ceramic-based composite material obtained by further impregnating ceramic into a preform formed of fiber-bonded three-dimensional ceramics and then firing.

The heat shield member is preferably used as a turbine shroud provided so as to cover a turbine rotor blade as the rotating body, with the clearance control layer facing the turbine rotor blade side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a heat shielding member having a clearance control layer according to the present invention will be described with reference to FIG. Drawing 1 is a figure showing a procedure of how to manufacture a heat shielding member of an embodiment. In order to obtain the heat shielding member of the embodiment, first, a preform made of a fiber-bonded three-dimensional ceramic having a shape as shown in FIG. 1 (a) is prepared, and further impregnated with ceramics and fired to obtain a ceramic base. Composite material (C
The base material 21 made of MC) is manufactured.

[0011] Fiber-bonded three-dimensional ceramics include, for example,
After melt-spinning polytitanocarbosilane, the material is made from inorganic fibers made of Si-Ti-C-O synthesized by infusibilization and firing, and the raw material fibers are pressed against the pressing direction during hot pressing. A three-dimensional fabric in which all the fibers extend vertically or diagonally is formed, and this three-dimensional fabric is heat-treated in air to form an oxidized fiber three-dimensional fabric having an oxidized layer on its surface, and the oxidized fiber three-dimensional fabric is pressed in the pressing direction. It is manufactured by hot press molding while making the oxide layers on the surface adhere to each other to form a matrix. Thus, a preform made of the fiber-bonded three-dimensional ceramic is completed. Then, this is further impregnated with ceramics and fired to obtain a base material 21 made of a ceramic-based composite material (CMC).

Since the base material 21 three-dimensionally weaves the fiber SX extending in the X-axis direction, the fiber SY extending in the Y-axis direction, and the fiber SZ extending in the Z-axis direction at the preform stage. It also has high fracture resistance in the thickness direction (Z-axis direction). In addition, a space (pocket) is provided at a portion where the triaxial fibers SX, SY, and SZ intersect.

Therefore, the surface of the base material 21 is
As shown in FIG. 1A, a ceramic 22 is plasma-sprayed to form a clearance control layer 23 made of a porous ceramic as shown in FIG. 1B, which is used as a heat shielding member. In this case, YSZ (yttria-stabilized zirconia) or the like is used as the sprayed ceramics 22 as in the related art.

When the thus obtained heat shielding member is used as a turbine shroud, the clearance control layer 23 is arranged on the outer peripheral side of the turbine moving blade so as to face the side in contact with the turbine moving blade. By doing so, the surface of the clearance control layer 23 is shaved by the outer periphery of the turbine blade, and the clearance with the turbine blade can be optimized.

In this case, the clearance control layer 2
The porous ceramic sprayed layer formed as 3 is
Since the anchoring effect is increased because the fine gaps (pockets) of the base material 21 made of the fiber-bonded three-dimensional ceramics are inserted, the clearance control layer 23 is hardly peeled off from the base material 21.

Further, since the base material 21 is also made of the same ceramics as the clearance control layer 23, the difference in thermal expansion between the base material 21 and the clearance control layer 23 becomes smaller than when a metal base material is used. , Which can prevent peeling. In addition, since the ceramic base composite material (CMC) having excellent heat shielding, high strength, and high toughness is used as the base material 21, the performance such as heat shielding and strength is improved as compared with the case where a metal base material is used. Get higher.

The heat shield member can be widely applied to other than the turbine shroud.

[0018]

As described above, the heat shielding member according to the present invention uses a fiber-bonded three-dimensional ceramic or a ceramic-based composite material obtained by impregnating and firing ceramic as the base material, and sprays the ceramic on the surface thereof. Thus, since the clearance control layer made of porous ceramics is formed, the difference in thermal expansion between the base material and the ceramic sprayed layer as the clearance control layer is reduced, and it is difficult to peel off at the boundary surface. In addition, the fiber-bonded three-dimensional ceramic or the ceramic-based composite material used for the base material has pockets, and the ceramic sprayed layer can penetrate the pockets, so that peeling can be further prevented.

When the base material is a metal as in the prior art, there is a concern that the base material is oxidized by oxygen passing through the porous ceramic layer (clearance control layer). There is no fear of oxidation, and durability and reliability are improved. Furthermore, since the thermal conductivity of the fiber-bonded three-dimensional ceramic or the ceramic-based composite material is lower than that of the metal base material, the cooling air amount of the member can be reduced.

Further, when the heat shielding member according to the present invention is used for a turbine shroud of a gas turbine, it can contribute to improvement of the efficiency of the gas turbine.

[Brief description of the drawings]

1A and 1B are diagrams showing a manufacturing procedure of a heat shielding member according to an embodiment of the present invention, in which FIG. 1A shows a state in which ceramics are sprayed on a surface of a base material, and FIG. FIG. 4 is a view showing a state in which a clearance control layer having a predetermined thickness made of a ceramic is formed.

FIG. 2 is a partial sectional view of the gas turbine.

FIG. 3 is a sectional view of a conventional turbine shroud.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine shroud (heat shielding member) 3 Turbine rotor blade (rotating body) 21 Base material 22 Ceramics 23 Clearance control layer

Claims (3)

[Claims] 1. A clearance control layer that is installed so as to cover the outer periphery of a rotating body and is shaved by the outer periphery of the rotating body to optimize clearance between the rotating body and the base material. A heat shielding member, wherein the base material is made of a fiber-bonded three-dimensional ceramic, and the ceramics are sprayed on a surface of the base material to form the clearance control layer made of a porous ceramic. A heat shield having a characteristic clearance control layer. 2. The ceramic base composite material according to claim 1, wherein the base material is formed by impregnating a ceramic into a preform formed of a fiber-bonded three-dimensional ceramic and further firing the ceramic. Heat shielding member having a clearance control layer. 3. A turbine shroud provided so as to cover a turbine rotor blade serving as the rotating body, wherein the clearance control layer is used facing the turbine rotor blade side. Heat shielding member having a clearance control layer.