A thermal barrier coating

Abstract

The present invention relates to the technical field of thermal barrier coatings, and particularly relates to a thermal barrier coating. An embodiment of the present invention provides a thermal barrier coating, which includes a thermal insulation layer. The thermal insulation layer includes a plurality of longitudinal cracks perpendicular to the thickness direction of the thermal insulation layer. One end of each longitudinal crack extends to the surface of the thermal insulation layer, and the other end is located inside the thermal insulation layer. The longitudinal cracks are filled with a heat-absorbing material. The composition of the thermal insulation layer includes a thermal barrier material, and the thermal barrier material contains oxides of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium. The embodiment of the present invention provides a thermal barrier coating with excellent heat insulation ability.

Description

Technical Field

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

[0002] A thermal barrier coating is a coating with heat insulation ability.

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

[0004] Embodiments of the present invention provide a thermal barrier coating with excellent heat insulation ability.

[0005] Embodiments of the present invention provide a thermal barrier coating, including a heat insulation layer. The heat insulation layer includes a plurality of longitudinal cracks perpendicular to the thickness direction of the heat insulation layer. One end of each longitudinal crack extends to the surface of the heat insulation layer, and the other end is located inside the heat insulation layer. The longitudinal cracks are filled with a heat-absorbing material. The composition of the heat insulation layer includes a thermal barrier material, and the thermal barrier material contains oxides of at least one of strontium, zirconium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium or yttrium.

[0006] In a possible design, the heat-absorbing material includes nano-sized kaolin, and the kaolin absorbs a 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 cracks 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 heat insulation layer.

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

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

[0012] In a possible design, the heat insulation layer further includes vacuum spheres with a vacuum environment inside.

[0013] In a possible design, the preparation material of the shell of the vacuum spheres includes silicon dioxide and / or aluminum oxide, and the outer diameter of the vacuum spheres is 5-10 μm.

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

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

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

[0017] In the present invention, the thermal barrier material can play an obvious heat insulation role at a thickness between dozens and hundreds of micrometers, and can protect the substrate to be protected by the thermal barrier coating from being affected by high temperature or being affected less by high temperature. Although the thermal barrier coating in the prior art can achieve a good heat insulation effect, when the ambient temperature rises instantaneously, its thermal shock stability is poor, which may lead to a decrease in the service life of the coating. 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. To improve its thermal shock stability, an endothermic material is filled in the longitudinal cracks. The endothermic material has excellent endothermic performance and a large latent heat. When the thermal barrier coating is subjected to an instantaneous high temperature impact, the endothermic material can absorb a large amount of heat, forming a buffering effect on the heat impact, 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 technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

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

[0020] In the figure:

[0021] 1 - Heat insulation layer;

[0022] 11 - Longitudinal crack;

[0023] 12 - Endothermic material;

[0024] 13 - Vacuum sphere;

[0025] 2 - Sealing layer;

[0026] 100 - Substrate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0028] In the description of the embodiments of the present invention, unless otherwise clearly defined or limited, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance. Unless otherwise specified or stated, the term "plurality" means two or more. Terms such as "connection" and "fixation" should be understood in a broad sense. For example, "connection" 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 those of ordinary skill in the art, 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 orientation terms such as "upper" and "lower" described in the embodiments of the present invention are described from the angles shown in the accompanying drawings and should not be construed 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 "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0030] Please refer to Figure 1 , the embodiments of the present invention provide a thermal barrier coating, including a thermal insulation layer 1. The thermal insulation layer 1 includes a plurality of longitudinal cracks 11 perpendicular to the thickness direction of the thermal insulation layer 1. One end of the longitudinal crack 11 extends to the surface of the thermal insulation layer 1, and the other end is located inside the thermal insulation layer 1. The longitudinal crack 11 is filled with a heat-absorbing material 12. The composition of the thermal insulation layer 1 includes a thermal barrier material, and the thermal barrier material contains oxides 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 have a thickness ranging from dozens to hundreds of micrometers and can play an obvious heat insulation role, protecting the substrate 100 to be protected by the thermal barrier coating from being affected by high temperatures or being less affected. Although the thermal barrier coatings in the prior art can achieve good heat insulation effects, their thermal shock stability is poor when the ambient temperature rises instantaneously, which may lead to a decrease in the service life of the coating. 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. To improve its thermal shock stability, an endothermic material 12 is filled in the longitudinal cracks. The endothermic material 12 has excellent endothermic properties and a large latent heat. When the thermal barrier coating is subjected to an instantaneous high-temperature impact, the endothermic material 12 can absorb a large amount of heat, forming a buffering effect for the heat impact, 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 endothermic material 12 includes nanoscale kaolin, and the kaolin absorbs a liquid.

[0034] In this embodiment, the endothermic material 12 can be kaolin that absorbs a liquid. The kaolin has a nanoscale particle size, and at the same time has water absorption and water retention properties and heat insulation properties. It can absorb and store a liquid with a large latent heat while ensuring the heat insulation performance of the heat insulation layer 1 for heat absorption buffering during a high-temperature shock. Natural kaolin can be processed by high temperature, acid treatment, and ultrasonic dispersion to obtain a nanoscale porous nanostructure. Its nanoscale particle size can enter the micron-scale longitudinal cracks 11 and absorb a high-latent heat liquid through capillary water absorption.

[0035] In this embodiment, in order to fill the endothermic material 12 into the longitudinal cracks 11, first, all gases are exhausted under vacuum negative pressure to make the longitudinal cracks 11 in a vacuum environment, facilitating the entry of the endothermic material 12 into the longitudinal cracks 11. Then, the endothermic material 12 is heated to cover the entire heat insulation layer 1. The part of the endothermic material 12 close to the longitudinal cracks 11 enters the longitudinal cracks 11. A positive pressure is comprehensively applied to the endothermic material 12 covering the heat insulation layer 1, and ultrasonic waves are applied to make the endothermic material 12 fill the longitudinal cracks 11.

[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 high latent heat. Preferably, in addition to having a high latent heat, the salt solution also has the advantage of reducing the thermal conductivity.

[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. With this setting, the heat-absorbing material 12 does not completely occupy the entire space of the longitudinal crack 11, leaving room for the heat-absorbing phase change expansion of the heat-absorbing material 12, preventing the longitudinal crack 11 from widening after the heat-absorbing material 12 undergoes heat-absorbing phase change expansion, and ultimately shortening the coating life.

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

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

[0042] In this embodiment, when the longitudinal crack 11 is within the above volume fraction range, the longitudinal crack 11, while absorbing the heat-absorbing material 12, the thermal insulation layer 1 has better thermal shock stability and a longer service life.

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

[0044] In this embodiment, a larger depth length can accommodate more heat-absorbing material 12, greatly improving 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 decrease.

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

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

[0047] When filling the longitudinal crack 11 with the solid-liquid phase change material, in order to avoid the expansion of the solid-liquid phase change material in the solid phase due to endothermic phase change and the enlargement of the longitudinal crack 11, an expansion space needs to be reserved 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 make it in a liquid phase. The vacuum environment prevents its oxidation. The heat insulation layer 1 is soaked with the liquid-phase solid-liquid phase change material, and a positive pressure is applied to the liquid-phase solid-liquid phase change material to make the liquid-phase solid-liquid phase change material immerse into the longitudinal crack 11. After the longitudinal crack 11 is filled, the material is taken out after cooling and depressurization. At this time, the solid-liquid phase change material shrinks into a solid phase and is located inside the longitudinal crack 11, and does not completely fill the longitudinal crack 11, leaving an expansion space for 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 sphere 13 with a vacuum environment inside.

[0049] In this embodiment, in order to further increase the heat insulation performance of the thermal barrier coating, a plurality of vacuum spheres 13 are further provided in the heat insulation layer 1. The inside of the vacuum sphere 13 is a vacuum environment, and vacuum cannot conduct heat, further increasing the heat insulation performance of the heat 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 external heat transfer to the substrate 100 layer is the thickness of the coating. However, in the heat insulation layer 1 provided with the vacuum spheres 13, due to the existence of the vacuum spheres 13, the cross-sectional area parallel to the surface of the substrate 100 is reduced, further increasing the heat insulation effect.

[0050] It should be noted that since the particle size of the vacuum sphere 13 is small and it is circular, it has strong compressive strength and can increase the compressive strength of the heat insulation layer 1 itself.

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

[0052] In this embodiment, the shell of the vacuum sphere 13 is a heat insulation material, which can ensure its heat insulation effect. At the same time, the material itself has strong strength. The outer diameter of the vacuum sphere 13 within the above range can balance the strength and heat insulation effect.

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

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

[0055] It can be understood that the longitudinal crack 11 has a very small area on the surface. During its operation, the internal heat-absorbing material 12 hardly contacts the air, and the degree of oxidation is relatively small. However, in order to further increase its oxidation resistance at high temperatures and extend its service life, a sealing layer 4 can be provided outside the heat insulation layer 1 to isolate the internal and external environments of its longitudinal crack 11.

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

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various 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 a heat-absorbing material (12), and the composition of 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; The heat absorbing material (12) comprises nano-scale kaolin, and the kaolin absorbs liquid.

2. The thermal barrier coating according to claim 1, 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.

3. The thermal barrier coating according to claim 1, characterized in that: The space in the longitudinal crack (11) is larger than the volume of the heat absorbing material (12).

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

5. 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).

6. 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.

7. 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.

8. The thermal barrier coating according to claim 7, 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.

9. The thermal barrier coating according to claim 1, characterized in that: A sealing layer (4) made of the thermal barrier material is provided on a side of the thermal insulation layer (1) away from the protective substrate (100), the sealing layer (4) being 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 50-500 μm, and the thickness of the sealing layer (4) is 5-20 μm.

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