Thermal barrier coating

Abstract

The invention relates to the technical field of thermal barrier coatings, in particular to a thermal barrier coating. The thermal barrier coating comprises a thermal insulation layer, the thermal insulation layer comprises a plurality of longitudinal cracks perpendicular to the thickness direction of the thermal insulation layer, one ends of the longitudinal cracks extend to the surface of the thermal insulation layer, the other ends of the longitudinal cracks are located in the thermal insulation layer, and the longitudinal cracks are filled with heat absorption materials. The thermal insulation layer comprises a thermal barrier material, and the thermal barrier material comprises oxide of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium. The thermal barrier coating provided by the embodiment of the invention has excellent thermal insulation capacity.

Description

Technical Field

[0001] The invention relates to the technical field of thermal barrier coatings, and in particular to a thermal barrier coating. Background Art

[0002] Thermal barrier coating is a coating with heat insulation capabilities.

[0003] In the aerospace field, engines, turbine blades and other components are in a high-temperature working environment. In order to protect the above components, thermal barrier coatings need to be sprayed on the surface of the above components to improve their heat resistance. Summary of the invention

[0004] The embodiment of the present invention provides a thermal barrier coating having excellent heat insulation capability.

[0005] An embodiment of the present invention provides a thermal barrier coating, comprising a thermal insulation layer, wherein the thermal insulation layer comprises a plurality of longitudinal cracks perpendicular to the thickness direction of the thermal insulation layer, wherein one end of the longitudinal cracks extends to the surface of the thermal insulation layer, and the other end is located inside the thermal insulation layer, and the longitudinal cracks are filled with heat-absorbing materials. The composition of the thermal insulation layer comprises a thermal barrier material, and the thermal barrier material comprises an oxide of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium.

[0006] In one possible design, the heat absorbing material includes nano-sized kaolin, and the kaolin absorbs liquid.

[0007] In a possible design, the liquid includes water and / or a salt solution, and the salt solution includes a phosphate solution, a chloride solution, and a fluoride solution.

[0008] In a possible design, the space in the longitudinal crack is larger than the volume of the heat absorbing material.

[0009] In a possible design, the volume of the longitudinal cracks accounts for 20-30% of the volume of the thermal insulation layer.

[0010] In a possible design, the longitudinal depth of the longitudinal crack is not less than 65-90% of the thickness of the thermal insulation layer.

[0011] In one possible design, the heat absorbing material includes at least one of a fatty acid solid-liquid phase change material and an alcohol solid-liquid phase change material.

[0012] In a possible design, the thermal insulation layer also includes a vacuum ball with a vacuum environment inside.

[0013] In a possible design, the shell of the vacuum ball is made of silicon dioxide and / or aluminum oxide, and the outer diameter of the vacuum ball is 5 to 10 μm.

[0014] In a possible design, a sealing layer made of the thermal barrier material is provided on one side of the thermal insulation layer away from the protective substrate, and the sealing layer is used to seal the opening of the longitudinal crack located on the surface of the thermal insulation layer;

[0015] The thickness of the heat insulation layer is 50-500 μm, and the thickness of the sealing layer is 5-20 μm.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] In the present invention, the thermal barrier material can have a thickness of tens to hundreds of microns, play a significant role in heat insulation, and can protect the substrate to be protected by the thermal barrier coating from or from being affected by a small amount of high temperature. Although the thermal barrier coating in the prior art can achieve a good insulation effect, its thermal shock stability is poor when the ambient temperature rises instantly, which may lead to a decrease in the service life of the coating. In order to solve the above problems, the present invention proposes a thermal barrier coating with a heat insulation layer having longitudinal cracks. The longitudinal cracks can improve the mechanical properties of the coating and also improve the heat insulation effect. In order to improve its thermal shock stability, a heat absorbing material is filled in the longitudinal cracks. The heat absorbing material has excellent heat absorption performance and large latent heat. When the thermal barrier coating is subjected to an instantaneous high temperature shock, the heat absorbing material can absorb a large amount of heat to form a buffering effect of the heat shock, thereby achieving the effect of improving the thermal stability of the thermal barrier coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of a thermal barrier coating provided in an embodiment of the present invention.

[0020] In the figure:

[0021] 1- Thermal insulation layer;

[0022] 11-longitudinal cracks;

[0023] 12-heat absorbing material;

[0024] 13- Vacuum ball;

[0025] 2- Sealing layer;

[0026] 100-base. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present invention are described at the angles shown in the drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0030] Please refer to Figure 1 An embodiment of the present invention provides a thermal barrier coating, including a thermal insulation layer 1, wherein the thermal insulation layer 1 includes a plurality of longitudinal cracks 11 perpendicular to the thickness direction of the thermal insulation layer 1, wherein one end of the longitudinal cracks 11 extends to the surface of the thermal insulation layer 1, and the other end is located inside the thermal insulation layer 1, and the longitudinal cracks 11 are filled with heat absorbing materials 12. The composition of the thermal insulation layer 1 includes a thermal barrier material, and the thermal barrier material includes an oxide of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium.

[0031] In the present invention, the thermal barrier material can play a significant role in heat insulation at a thickness of tens to hundreds of microns, and can protect the substrate 100 to be protected by the thermal barrier coating from or from being affected by a small amount of high temperature. Although the thermal barrier coating in the prior art can achieve a good insulation effect, its thermal shock stability is poor when the ambient temperature rises instantly, which may lead to a decrease in the service life of the coating. In order to solve the above problems, the present invention proposes a thermal barrier coating with a heat insulation layer 1 having longitudinal cracks 11. The longitudinal cracks can improve the mechanical properties of the coating and also improve the heat insulation effect. In order to improve its thermal shock stability, a heat absorbing material 12 is filled in the longitudinal cracks. The heat absorbing material 12 has excellent heat absorption performance and large latent heat. When the thermal barrier coating is subjected to an instantaneous high temperature shock, the heat absorbing material 12 can absorb a large amount of heat to form a buffering effect of the heat shock, thereby achieving the effect of improving the thermal stability of the thermal barrier coating.

[0032] In this embodiment, the heat insulation layer 1 can be formed on the substrate 100 by plasma spraying technology.

[0033] In some embodiments of the present invention, the heat absorbing material 12 includes nano-sized kaolin clay that absorbs liquid.

[0034] In this embodiment, the heat absorbing material 12 can be kaolin that absorbs liquid. The kaolin has nano-scale particle size, water absorption and water retention properties, and heat insulation properties. It can absorb and store liquid with large latent heat while ensuring the insulation performance of the heat insulation layer 1, so as to absorb heat and buffer during high heat shock. Natural kaolin can be obtained into a nano-scale porous nanostructure through high temperature treatment, acid treatment and ultrasonic dispersion. Its nano-scale particle size can enter the micron-scale longitudinal cracks 11 and absorb high latent heat liquid through capillary water absorption.

[0035] In this embodiment, in order to fill the longitudinal crack 11 with the heat absorbing material 12, all gases are first exhausted under vacuum negative pressure to place the longitudinal crack 11 in a vacuum environment, which facilitates the heat absorbing material 12 to enter the longitudinal crack 11. Then, the heat absorbing material 12 is heated to cover the entire thermal insulation layer 1, and the heat absorbing material 12 near the longitudinal crack 11 partially enters the longitudinal crack 11. A positive pressure is applied to the heat absorbing material 12 covering the thermal insulation layer 1, and ultrasonic waves are applied to fill the longitudinal crack 11 with the heat absorbing material 12.

[0036] In some embodiments of the present invention, the liquid includes water and / or a salt solution, and the salt solution includes a phosphate solution, a chloride solution, and a fluoride solution.

[0037] In this embodiment, water has a relatively high latent heat. Preferably, the salt solution has the advantage of reducing thermal conductivity in addition to having a relatively high latent heat.

[0038] In some embodiments of the present invention, the space in the longitudinal crack 11 is larger than the volume of the heat absorbing material 12 .

[0039] In this embodiment, the space inside the longitudinal crack 11 is larger than the volume of the heat-absorbing material 12 itself. In this way, the heat-absorbing material 12 does not completely occupy the entire space of the longitudinal crack 11, and space is reserved for the heat-absorbing phase change expansion of the heat-absorbing material 12, thereby preventing the heat-absorbing material 12 from widening the longitudinal crack 11 after the heat-absorbing phase change expansion, thereby ultimately shortening the coating life.

[0040] After the heat absorbing material 12 fills the longitudinal cracks 11, the heat absorbing material 12 often completely fills the cracks. In order to make the heat absorbing material 12 partially occupy the longitudinal cracks 11, part of the liquid can be removed after the heat absorbing material 12 completely fills the cracks. Specifically, when the liquid is water, the water in part of the longitudinal cracks 11 can be precisely evaporated by controlling the temperature, humidity and heating time; when the liquid is a salt solution, a salt solution lower than a preset concentration can be first prepared, and then the water in the salt solution in part of the longitudinal cracks 11 can be precisely evaporated by controlling the temperature, humidity and heating time to increase the concentration and reduce the volume.

[0041] In some embodiments of the present invention, the volume of the longitudinal cracks 11 accounts for 20-30% of the volume of the thermal insulation layer 1 .

[0042] In this embodiment, when the longitudinal cracks 11 are within the above volume fraction range, the longitudinal cracks 11 absorb the heat absorbing material 12 and the heat insulation layer 1 has good thermal shock stability and a long service life.

[0043] In some embodiments of the present invention, the depth of the longitudinal crack 11 is not less than 65-90% of the thickness of the thermal insulation layer 1 .

[0044] In this embodiment, the greater longitudinal depth can accommodate more heat-absorbing materials 12 and greatly improve the thermal shock stability, but the longitudinal crack 11 cannot completely penetrate the thermal insulation layer 1. If it completely penetrates, the service life of the thermal insulation layer 1 will be reduced.

[0045] In some embodiments of the present invention, the heat absorbing material 12 includes at least one of a fatty acid solid-liquid phase change material and an alcohol solid-liquid phase change material.

[0046] In this embodiment, both the fatty acid splitting solid-liquid phase change material and the alcohol solid-liquid phase change material have high latent heat and can absorb more heat during phase change. The two have good miscibility and their application can further expand the temperature range of adjusting phase change.

[0047] When the solid-liquid phase change material is filled in the longitudinal crack 11, in order to avoid the solid-phase solid-liquid phase change material absorbing heat and expanding the phase change, and to expand the longitudinal crack 11, it is necessary to reserve expansion space in the longitudinal crack 11, and the longitudinal crack 11 can be filled in a high-temperature vacuum environment. Specifically, the solid-liquid phase change material is heated in a vacuum environment to be in a liquid phase, and the vacuum environment prevents its oxidation. The liquid-phase solid-liquid phase change material is used to soak the thermal insulation layer 1, and a positive pressure is applied to the liquid-phase solid-liquid phase change material, so that the liquid-phase solid-liquid phase change material is immersed in the longitudinal crack 11. After the longitudinal crack 11 is filled, the temperature and pressure are reduced, and the material is taken out. At this time, the solid-liquid phase change material shrinks to a solid phase and is located inside the longitudinal crack 11, and does not completely fill the longitudinal crack 11, leaving expansion space for the endothermic phase change in the later use stage.

[0048] In some embodiments of the present invention, the heat insulation layer 1 further includes a vacuum ball 13 whose interior is a vacuum environment.

[0049] In this embodiment, in order to further increase the thermal insulation performance of the thermal barrier coating, a plurality of vacuum balls 13 are further provided in the thermal insulation layer 1. The interior of the vacuum balls 13 is a vacuum environment, and the vacuum cannot conduct heat, which further increases the thermal insulation performance of the thermal insulation layer 1. In addition, under the same heat transfer path, the smaller the cross-sectional area of ​​heat transfer, the slower the heat conduction speed. The path length of the heat from the outside to the substrate 100 layer is the thickness of the coating. However, in the thermal insulation layer 1 provided with the vacuum balls 13, due to the presence of the vacuum balls 13, the cross-sectional area of ​​the surface parallel to the substrate 100 is reduced, which further increases the thermal insulation effect.

[0050] It should be noted that, since the vacuum balls 13 have a small particle size and are round in shape, they have strong compressive strength and can increase the compressive strength of the thermal insulation layer 1 itself.

[0051] In some embodiments of the present invention, the shell of the vacuum ball 13 is made of silicon dioxide and / or aluminum oxide, and the outer diameter of the vacuum ball 13 is 5-10 μm.

[0052] In this embodiment, the shell of the vacuum ball 13 is made of heat-insulating material, which can ensure its heat-insulating effect. At the same time, the material itself has strong strength. The outer diameter of the vacuum ball 13 within the above range can take into account both strength and heat-insulating effect.

[0053] In some embodiments of the present invention, a sealing layer 4 made of a thermal barrier material is provided on one side of the thermal insulation layer 1 away from the protective substrate 100, and the sealing layer 4 is used to seal the opening of the longitudinal crack 11 located on the surface of the thermal insulation layer 1;

[0054] The thickness of the heat insulating layer 1 is 50 to 500 μm, and that of the sealing layer 4 is 5 to 20 μm.

[0055] It can be understood that the area of ​​the longitudinal crack 11 located on the surface is extremely small. During its operation, the internal heat-absorbing material 12 is almost not in contact with the air, and the degree of oxidation is relatively small. However, in order to further increase its oxidation resistance at high temperatures and increase its service life, a sealing layer 4 can be provided on the outside of the insulation layer 1 to isolate the longitudinal crack 11 from the internal and external environments.

[0056] It should be noted that after obtaining the heat insulating layer 1 filled with the heat absorbing material 12 , the sealing layer 4 can be sprayed in an oxygen-free environment by using the ion spraying technology.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal barrier coating, characterized in that: The invention comprises a heat-insulating layer (1), wherein the heat-insulating layer (1) comprises a plurality of longitudinal cracks (11) perpendicular to the thickness direction of the heat-insulating layer (1), wherein one end of the longitudinal cracks (11) extends to the surface of the heat-insulating layer (1), and the other end is located inside the heat-insulating layer (1), and the longitudinal cracks (11) are filled with heat-absorbing materials (12). The heat-insulating layer (1) comprises a thermal barrier material, and the thermal barrier material comprises an oxide of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium.

2. The thermal barrier coating according to claim 1, characterized in that: The heat absorbing material (12) comprises nano-scale kaolin, and the kaolin absorbs liquid.

3. The thermal barrier coating according to claim 2, characterized in that: The liquid includes water and / or a salt solution, and the salt solution includes a phosphate solution, a chloride solution, and a fluoride solution.

4. The thermal barrier coating according to claim 2, characterized in that: The space in the longitudinal crack (11) is larger than the volume of the heat absorbing material (12).

5. The thermal barrier coating according to claim 1, characterized in that: The volume of the longitudinal cracks (11) accounts for 20 to 30% of the volume of the thermal insulation layer (1).

6. The thermal barrier coating according to claim 1, characterized in that: The longitudinal depth of the longitudinal crack (11) is not less than 65-90% of the thickness of the thermal insulation layer (1).

7. The thermal barrier coating according to claim 1, characterized in that: The heat absorbing material (12) comprises at least one of a fatty acid solid-liquid phase change material and an alcohol solid-liquid phase change material.

8. The thermal barrier coating according to claim 1, characterized in that: The heat insulation layer (1) also includes a vacuum ball (13) whose interior is a vacuum environment.

9. The thermal barrier coating according to claim 8, characterized in that: The shell of the vacuum ball (13) is made of silicon dioxide and / or aluminum oxide, and the outer diameter of the vacuum ball (13) is 5 to 10 μm.

10. The thermal barrier coating according to claim 1, characterized in that: A sealing layer (4) made of the thermal barrier material is provided on the side of the thermal insulation layer (1) away from the protective substrate (100), and the sealing layer (4) is used to seal the opening of the longitudinal crack (11) located on the surface of the thermal insulation layer (1); The thickness of the heat insulation layer (1) is 50 to 500 μm, and the thickness of the sealing layer (4) is 5 to 20 μm.

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