JPH11124662A - Self-repairing heat-insulating film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-insulating film capable of prolonging thermal fatigue life by self-repairing micro cracks due to repeated heating and cooling, and its production. SOLUTION: As to this self-repairing heat-insulating film, a ZrO2 type ceramic film is formed as a top coating layer 13 and a bond coating layer 12 to be a ground coat is formed into a gradient layer composed of NiCrAlY alloy and ZrO2 Y2 O3 , and further, the component concentration of Zr is decreased on the base material 11 side and is made gradient so that it is increased with the approach to the top coating layer 13 side. By this method, the heat-insulating film having self-repairing property can be obtained and thermal fatigue life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-healing heat-insulating film and a method for manufacturing the same, and more particularly to a heat-insulating film capable of self-healing micro cracks caused by repeated heating and cooling, and a method for manufacturing the same. is there.

[0002]

2. Description of the Related Art In equipment used in a high-temperature environment such as an aircraft engine, a boiler, and a refuse disposal apparatus, a base material is protected from high temperatures by providing a heat insulating film on the base material surface.

As such a heat insulating film, for example, a ZrO2 ceramic film is formed on the inner wall of a combustion chamber of an aircraft jet engine by plasma spraying.

When the ZrO2 ceramic coating is subjected to plasma spraying, after the surface to be sprayed of the base metal is blast-treated, as shown in FIG. NiCrA as film
The Y alloy 2 is plasma-sprayed, and a ZrO2-based ceramic 3 which is a heat insulating film is plasma-sprayed on the undercoat 2.

[0005]

However, in the heat insulating coating 4 composed of such a two-layer coating of the ZrO2 ceramics 3 formed by plasma spraying, the combustion chamber of an aircraft jet engine in which heating and cooling are repeatedly performed. When used for a wall or the like, there is a problem that micro-cracks are generated in the coating film 4 due to thermal strain, and the cracks gradually grow, thereby shortening the thermal fatigue life.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and a heat insulating film capable of extending a thermal fatigue life by self-repairing micro cracks generated when heating and cooling are repeated, and a method of manufacturing the same. Is to provide.

[0007]

According to a first aspect of the present invention, there is provided a self-healing heat-insulating coating comprising: a bond coating layer provided on a surface of a base material and serving as a base;
A heat-insulating coating comprising a heat-insulating top coating layer provided through the bond coating layer, wherein the bond coating layer is constituted by a gradient layer in which the component concentration is changed from the substrate side toward the top coating layer. It is characterized by having done.

[0008] Here, the self-healing property means a function of eliminating an initial fatigue crack. According to this self-healing heat insulating film, the bond coating layer serving as a base provided between the substrate surface and the top coating layer as the heat insulating film is a gradient layer in which the component concentrations are sequentially changed, and this gradient layer is provided. In the thermal barrier coating, the crack propagation phenomenon observed when the temperature rises tends to shrink and disappear as the temperature decreases, and it has been confirmed by an experiment that it has self-healing properties against microcracks.

According to a second aspect of the present invention, there is provided a self-healing heat insulating film according to the first aspect, wherein the top coating layer is a ZrO2 ceramic film, and the bond coating layer is NiCrAlY. Alloy and ZrO2
A gradient layer composed of Y2 O3, wherein the component concentration of NiCrAlY alloy is high on the base material side, and the component concentration of ZrO2Y2O3 is high on the top coating layer side. It is.

According to this self-healing heat insulating film, a specific heat insulating film is Zr as a top coating layer.
An O2-based ceramic film is formed, and a bond coating layer serving as an underlayer is a gradient layer composed of NiCrAlY alloy and ZrO2Y2O3. On the base material side, the component concentration of Zr is reduced, and this is changed to a top coating layer side. In order to obtain a heat-insulating film having a self-healing property, the thermal fatigue life is prolonged.

Further, according to a third aspect of the present invention, there is provided a method for producing a self-healing heat insulating film, comprising: a bond coating layer provided on the surface of the base material and serving as a base; and a heat insulating film provided via the bond coating layer. When forming a heat insulating film composed of a top coating layer, the bond coating layer is formed by inclining the component concentration from the substrate side toward the top coating layer by plasma spraying, and then the top coating layer is plasma sprayed. It is characterized by being formed by.

According to the method for producing a self-healing heat insulating film, the bond coating layer serving as the base is formed by plasma spraying with the component concentration being inclined from the substrate side toward the top coating layer, and then the heat insulating top layer is formed. The coating layer is formed by plasma spraying, and the thermal insulation coating provided with the bond coating layer with the gradient of component concentration shows that the crack expansion phenomenon seen when the temperature rises tends to shrink and disappear as the temperature decreases. It has been confirmed through experiments that it has self-healing properties against microcracks.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a self-healing heat-insulating coating according to the third aspect, wherein the bond coating layer is formed of NiC on the substrate side.
r Al Y alloy has a high component concentration, and on the top coating layer side, ZrO2Y2O3 component concentration is increased and plasma sprayed, and then ZrO2 ceramic is plasma sprayed to form the top coating layer. It is assumed that.

According to this method for producing a self-healing heat-insulating coating, as a specific heat-insulating coating, the bond concentration of the NiCrAlY alloy is increased on the substrate side, and ZrO2 on the top coating layer side. After increasing the component concentration of Y2 O3 and forming by plasma spraying, a ZrO2 based ceramic is plasma sprayed to form a top coating layer, thereby obtaining a self-healing heat insulating film and a thermal fatigue life. I try to make it longer.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a self-healing heat-insulating coating of the present invention and a method for manufacturing the same will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view according to one embodiment of the self-healing heat insulating film of the present invention.

The self-healing heat-insulating coating 10 comprises a substrate 11
Is formed of a bond coating layer 12 serving as an underlayer and a top coating layer 13 having heat insulating properties, but the bond coating layer 12 is not a single layer but is formed of a gradient layer in which the component concentrations are sequentially changed.

The base material 11 of the self-healing heat-insulating coating 10 is made of a metal material such as stainless steel, carbon steel, or a heat-resistant metal, and the top coating layer 13 is made of a heat-insulating ceramic material. Can be Also. As the bond coating layer 12 serving as a base, a metal-based alloy, a ceramic material, or a mixture thereof is used. From the properties close to the base material, the concentrations of the components are sequentially changed to change the properties close to the top coating layer. It becomes a graded layer.

The bond coating layer 12 and the top coating layer 13 are formed by a plasma spraying method.
100% on the side, and this is the bond coating layer 12
Is formed in a plurality of layers at 0% on the surface, or is formed in a gradient layer so as to have a continuous component concentration.

By using such plasma spraying,
The inclined layer can be easily formed, and the self-healing heat insulating film 10 can be obtained.

The heat-insulating coating 1 having the top coating layer 13 made of a heat-insulating ceramic due to the presence of the bond coating layer 12 made of such a gradient layer.
In the case of 0, the crack width of the micro-crack tends to increase as the temperature rises by experiments with repeated heating and cooling, but it has been confirmed that the crack width tends to shrink when the temperature decreases due to cooling. I found that there is.

Although the mechanism of this self-healing property is not always clear, since the bond coating layer 12 is formed as a gradient layer, the bond between the metal of the base material 11 and the top coating layer 13 of the heat insulating ceramic is provided. Although there is a difference in the coefficient of thermal expansion, it may be one of the factors that the difference in the coefficient of thermal expansion between adjacent particles is small and changes continuously. Top coating layer 13 from material 11 side
It is conceivable that one of the factors may be that a part of the alloy component whose component concentration is changed toward the temperature is melted when the temperature rises and melts out along the crack.

According to such a self-healing heat-insulating coating 10, even if a micro-crack is generated due to the self-healing property of the heat-insulating coating itself, it is repaired, and the thermal fatigue life is not shortened by the expansion of the conventional micro-cracks. , Can extend the thermal fatigue life.

[0023]

Next, a specific example of the self-healing heat insulating film 10 and a method of manufacturing the same will be described.

1) Test Material Stainless steel and carbon steel were prepared as base materials for the self-healing heat-insulating coating (both 100 × 50 × 30). Particle size of 44 to 10 μm as a thermal spray material for the bond coating layer
m of NiCrAlY alloy powder (Ni: 76.24, Cr: 1
7.06, Al: 5.84, Y: 0.27%) and 8 vol% Y2O3
Zr O2 powder (Z
rO2.8% Y2O3, hereinafter simply referred to as 8YSZ. ) Were prepared and mixed for use.

Then, in order to make the bond coating layer an inclined layer, the base material side is made of 100% concentration of NiCrAlY alloy powder, and a mixture of NiCrAlY alloy powder and 8YSZ is mixed with NiCrAlY powder. 90% Al Y alloy powder
8YSZ is increased by 10% from 10% while the outermost surface is made of NiCrAlY alloy powder with 10% and 8Y.
SZ was adjusted to 90%.

As the thermal spray material for the top coating layer, 8YSZ prepared for the gradient layer of the bond coating layer was used.

2) Formation of Coating The formation of the thermal spray coating by the plasma spraying method is performed in advance by using the base material 11
Blast treatment (# 36 alumina grit,
After air pressure of 5 kg / cm 2), only NiCrAlY alloy powder (100%) was plasma sprayed as the first layer of the bond coating layer 12. The plasma spraying in this case was performed under the spraying conditions shown in Table 1.

A mixture of two components, NiCrAlY alloy powder and 8YSZ, was sprayed onto the plasma sprayed coating of 100% concentration NiCrAlY alloy powder while changing the respective component concentrations. The thickness of the entire bond coating layer 12 was about 0.3 mm.

After the bond coating layer 12 thus formed as the inclined layer was formed by plasma spraying, only 8YSZ (100%) was plasma sprayed as the top coating layer 13 to a thickness of about 0.2 mm. The plasma spraying in this case was performed under the spraying conditions shown in Table 1.

[0030]

[Table 1]

3) Evaluation of thermal insulation film In order to evaluate the 8YSZ-NiCrAlY alloy film, the heating, cooling and repetition in an argon gas atmosphere using a high-temperature microscope are used to evolve and reduce cracks generated in the cross section of the film. The annihilation situation was observed. In this case, the temperature range is set from room temperature to 950 ° C., and the heating and cooling times are each set to one.
The retention time at 950 ° C. was 0 minute and 1 minute. As a result, microcracks were found to occur with increasing temperature in both the stainless steel base and the carbon steel base, but the microcracks conversely shrank during the cooling process, and almost normal temperature It was confirmed that it had returned to its original state and exhibited self-healing properties.

Further, in order to clarify the self-healing property of the heat insulating film, attention is paid to one of the micro cracks generated in the film, the change in the width of the micro crack is measured, and the relationship between the crack width and the temperature is examined. The results are shown in FIGS.

As is clear from the figure, in any of the thermal insulation coatings shown in FIG. 2 showing the case where the base material is made of stainless steel and FIG. 3 showing the case where the base material is made of carbon steel, cracks are generated with increasing temperature. Although the width was increased, it was reduced during the cooling process, indicating that this heat insulating film has self-healing properties.

The thermal fatigue life was also evaluated. As shown in FIG. 4, the self-healing heat-insulating coating of the present invention was 100% NiCr as a conventional bond coating layer.
It has been found that the life can be greatly increased as compared with the one made of the AlY alloy film.

[0035]

According to the self-healing heat-insulating coating according to the first aspect of the present invention, as described above in detail with reference to one embodiment, the distance between the surface of the base material and the top coating layer as the heat-insulating coating is improved. In the thermal insulation coating with this graded layer, the crack expansion phenomena observed when the temperature rises tend to shrink and disappear as the temperature decreases, because the bond coating layer, which is the base layer to be provided, is a graded layer in which the component concentrations are changed sequentially. Was observed, and it was confirmed by an experiment that it had self-healing properties against microcracks.

According to the self-healing heat-insulating film of the second aspect of the present invention, as a specific heat-insulating film, a ZrO2-based ceramic film is formed as a top coating layer, and a bond coating layer serving as a base is formed. Ni Cr Al
A gradient layer composed of a Y alloy and ZrO2Y2O3 is formed. The component concentration of Zr is lowered on the base material side, and is gradually increased on the top coating layer side. A film can be obtained and the thermal fatigue life can be extended.

Further, according to the method for producing a self-healing heat-insulating coating according to the third aspect of the present invention, the component concentration of the bond coating layer as a base is inclined from the substrate side toward the top coating layer by plasma spraying. After forming, the thermal insulation top coating layer was formed by plasma spraying, so the thermal insulation coating provided with the bond coating layer with the gradient of the component concentration caused the crack expansion phenomenon seen at the time of temperature rise to increase. The tendency to shrink and disappear with the decrease of the temperature was observed, and it was confirmed by an experiment that there was a self-healing property against micro cracks.

According to the method for producing a self-healing heat-insulating film according to the fourth aspect of the present invention, as a specific heat-insulating film, a bond coating layer is formed of NiCrAlY on the substrate side.
Increase the alloy component concentration, and on the top coating layer side,
After the ZrO2Y2O3 component concentration is increased and formed by plasma spraying, the ZrO2 based ceramic is plasma sprayed to form a top coating layer, thereby obtaining a self-healing heat insulating film. As well as prolonging the thermal fatigue life.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view according to an embodiment of a self-healing heat insulating film of the present invention.

FIG. 2 is a graph showing a relationship between a crack width and a temperature in a heating and cooling process according to an embodiment of the self-healing heat insulating film of the present invention.

FIG. 3 is a graph showing a relationship between a crack width and a temperature in a heating and cooling process according to another embodiment of the self-healing heat insulating film of the present invention.

FIG. 4 is a graph showing a thermal fatigue life according to an embodiment of the self-healing heat insulating film of the present invention.

FIG. 5 is a cross-sectional view showing the structure of a conventional two-layer heat insulating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Self-healing thermal insulation film 11 Substrate 12 Bond coating layer 13 Top coating layer

Claims (4)

[Claims] 1. A heat insulating film comprising a bond coating layer provided on a base material surface and serving as a base, and a heat insulating top coating layer provided via the bond coating layer, wherein the bond coating layer is A self-healing heat-insulating coating, comprising a gradient layer in which the component concentration is changed from the substrate side toward the top coating layer. 2. The method according to claim 1, wherein the top coating layer is a ZrO2 ceramic coating, and the bond coating layer is Ni.
The gradient layer is composed of a CrAlY alloy and ZrO2Y2O3, and the NiCrAlY alloy has a high component concentration on the base material side, and the ZrO2Y2O3
2. The self-healing heat-insulating coating according to claim 1, wherein the component concentration of O2 Y2 O3 is increased. 3. When forming a heat insulating film composed of a bond coating layer provided on a base material surface and serving as a base, and a heat insulating top coating layer provided through the bond coating layer, the bond coating layer A method for producing a self-healing heat-insulating coating, characterized in that a component concentration is inclined from the substrate side to the top coating layer by plasma spraying, and then the top coating layer is formed by plasma spraying. 4. The bond coating layer is plasma-sprayed by increasing the component concentration of NiCrAlY alloy on the base material side and increasing the component concentration of ZrO2Y2O3 on the top coating layer side. The method for producing a self-healing heat-insulating coating according to claim 3, wherein the top coating layer is formed by plasma spraying a system ceramic.