A locally adaptive porous substrate incorporating a coating sublimation and method of making the same

Abstract

The application discloses a preparation method of a local self-adaptive porous base combined with a coating sublimation, which is composed of the following steps: screening coating materials according to the safety temperature of the porous base, the sublimation point temperature of the selected coating material is less than or equal to the safety temperature of the porous base minus a predetermined temperature, mixing each coating material with the required additive in the spraying process to obtain a coating material mixture, performing a thermogravimetric analysis on the coating material mixture, obtaining the weight loss and residual amount of each coating material mixture through the test, selecting the coating material mixture with a weight loss ratio greater than or equal to 96% and a residual amount less than or equal to 4% under the condition of being higher than the sublimation point temperature of the coating material, and brushing the coating material mixture to the heated side of the porous base to obtain a self-adaptive porous base; the application can effectively and timely clean dust particles or carbon black impurities caused by incomplete combustion of the flame, can keep the inside of the porous base full of coolant all the time, and is not prone to overheating and thermal damage.

Description

Technical Field

[0001] This invention belongs to the field of heat transfer and flow, and particularly relates to a locally adaptive porous matrix with coating sublimation and its preparation method. Background Technology

[0002] Sweating cooling technology can be considered a biomimetic technology. This technology reduces the surface temperature in high-temperature environments by "sweating," thereby achieving the purpose of thermal protection. During the sweating cooling process, the cooling fluid first flows through the porous wall surface and undergoes strong convection to transfer heat away. Subsequently, a dense liquid film or gas film is formed on the surface of the wall to reduce the heat transfer from the high-temperature mainstream to the wall surface.

[0003] However, in many high-temperature environments, the heat flux density distribution on the heated surface is usually uneven. In localized overheating areas, the coolant evaporates into a gaseous state, increasing fluid resistance and causing a vapor blockage effect. The coolant avoids the overheated vapor zone within the porous material and seeps out through other interconnected channels with lower flow resistance, resulting in higher temperatures in the localized overheating areas, lower cooling efficiency, and even localized high-temperature heat loss in the porous structure. Simultaneously, the uneven temperature distribution on the heated surface and the lower flow rate of the cooling medium in the localized high-temperature areas cause the coolant to preferentially flow out from areas with lower surface heat load. The hot side surface cannot receive a reasonable distribution of coolant. Increasing the coolant supply flow rate can mitigate localized overheating, but it also easily leads to coolant waste and increased negative quality of the equipment.

[0004] A series of problems caused by steam blockage can be overcome by changing the distribution of physical parameters such as the thickness, porosity, and pore size of the porous matrix. However, the process is relatively complex and difficult. Furthermore, it is difficult to design and manufacture a sweating cooling structure that can adapt to the heat flux density distribution under complex or unclear conditions. These shortcomings have hindered the application of sweating cooling in hypersonic new space launch vehicles. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a locally adaptive porous substrate that combines coating sublimation, in order to solve the problems of local overheating, uneven temperature distribution on the heated surface, and difficulty in adapting to complex or unclear heat flux density distribution in existing porous sweating cooling.

[0006] This invention employs the following technical solution: a method for preparing a locally adaptive porous matrix combined with coating sublimation, comprising the following steps:

[0007] Step 1: Select coating materials based on the safe temperature of the porous substrate. The sublimation point temperature of the selected coating material should be ≤ the safe temperature of the porous substrate - the predetermined temperature.

[0008] Step 2: Mix the various coating materials with the additives required during the spraying process to obtain a coating material mixture. Perform thermogravimetric analysis on the coating material mixture to obtain the weight loss and residual amount of each coating material mixture through experiments.

[0009] Step 3: Select a coating material mixture with a weight loss ratio ≥96% and a residual amount ≤4% under conditions above the sublimation temperature of the coating material. Apply this coating material mixture to the heated side of the porous substrate to obtain an adaptive porous substrate.

[0010] The heated side surface of the porous substrate is divided into an exposed area and a coated area. The coated area is coated with a coating material mixture and is used to completely seal the pores on the porous substrate except for the exposed area during sweating and cooling, thereby preventing the leakage of coolant. The exposed area is the exposed heated side surface of the porous substrate and is used to guide the coolant and concentrate its seepage from the exposed area.

[0011] Furthermore, in step 1, two coating materials can be selected, namely a first coating material and a second coating material. The predetermined temperature of the first coating material is 201-400℃, and the predetermined temperature of the second coating material is 100-200℃.

[0012] The first coating material is mixed with the additives required in the spraying process to obtain the first coating mixture; the second coating material is mixed with the additives required in the spraying process to obtain the second coating mixture.

[0013] The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring with the exposed area as the center. The second coating area is far from the exposed area and extends outward in a ring with the exposed area as the center and touches the first coating area.

[0014] The first coating mixture is applied to the first coating area, and the second coating mixture is applied to the second coating area; the coating thickness of the first coating mixture is less than the coating thickness of the second coating mixture.

[0015] Further, in step 1, a coating material is selected, the predetermined temperature of which is 201-400℃ and the thickness of the coating in the coating area is 50-200μm.

[0016] Furthermore, the coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring with the exposed area as the center. The second coating area is far from the exposed area and extends outward in a ring with the exposed area as the center and touches the first coating area. The coating thickness of the first coating area is less than the coating thickness of the second coating area.

[0017] Furthermore, the coating area is positioned around the exposed area, and the exposed area is circular, square, or rectangular.

[0018] Furthermore, the porous matrix is ​​a stainless steel porous plate, a nickel-based alloy porous plate, or a C / SiC composite porous plate. The safe temperature of the nickel-based alloy porous plate is 1000℃, the safe temperature of the C / SiC composite porous plate is 1650℃, and the safe temperature of the stainless steel porous plate is 600℃. The porosity of the porous matrix is ​​10%-40%, and the pore size of the porous matrix is ​​5-100μm.

[0019] Furthermore, the method for coating the coating area in step 3 is as follows:

[0020] The porous substrate is cleaned to remove impurities and then dried.

[0021] Affix a label to the exposed area on the heated side of the porous substrate.

[0022] Apply the coating material mixture repeatedly and evenly to the heated side of the porous substrate, remove the label, and let it stand.

[0023] Furthermore, the method for coating the coating area in step 3 is as follows:

[0024] The porous substrate is cleaned to remove impurities and then dried.

[0025] Labels are affixed to the exposed areas on the heated side of the porous substrate and to the first coating area.

[0026] The second coating mixture was repeatedly and evenly applied to the heated side of the porous substrate, and the label was removed and allowed to stand.

[0027] Labels are affixed to the exposed areas on the heated side of the porous substrate and to the second coating area.

[0028] The first coating mixture is repeatedly and evenly applied to the heated side of the porous substrate, and the label is removed and allowed to stand.

[0029] A locally adaptive porous matrix incorporating coating sublimation, comprising:

[0030] The porous substrate has a heated surface divided into an exposed area and a coated area. The coated area is further divided into a first coated area and a second coated area. The first coated area is close to the exposed area and extends outward in a ring shape with the exposed area as its center. The second coated area is far from the exposed area and extends outward in a ring shape with the exposed area as its center, and is in contact with the first coated area.

[0031] An adaptive coating is applied to a first coating region and a second coating region of a porous substrate, wherein the coating thickness in the first coating region is less than the coating thickness in the second coating region.

[0032] The coating material mixtures for the first coating area and the second coating area are the same.

[0033] A locally adaptive porous matrix incorporating coating sublimation, comprising:

[0034] The porous substrate has a heated surface divided into an exposed area and a coated area. The coated area is further divided into a first coated area and a second coated area. The first coated area is close to the exposed area and extends outward in a ring shape with the exposed area as its center. The second coated area is far from the exposed area and extends outward in a ring shape with the exposed area as its center, and is in contact with the first coated area.

[0035] The first adaptive coating is applied to the first coating area of ​​the porous substrate.

[0036] The second adaptive coating is applied to the second coating area of ​​the porous substrate.

[0037] The coating materials of the first adaptive coating and the second adaptive coating are different, and the coating thickness of the first coating area is less than that of the second coating area.

[0038] The beneficial effects of this invention are:

[0039] 1. In this invention, coolant is always flowing through the exposed area at a certain small flow rate, and the coolant will continuously flow over the coating surface, which can effectively and timely clean dust particles or carbon black impurities from incomplete combustion of flame. On the other hand, due to the coverage of coolant on the porous substrate surface, some impurities with a certain temperature are not easy to undergo thermal reaction or adhesion with the coating, thereby damaging the coating. Therefore, it also protects the coating itself.

[0040] 2. The coating thickness of the first coating mixture of the present invention is less than that of the second coating mixture, that is, the coating thickness of the first coating mixture is 20 to 40 micrometers and the coating thickness of the second coating mixture is 41 to 60 micrometers; this is beneficial for the first coating area to preferentially sublimate and expose the pores, and to perform sweating and cooling. That is, the coating thickness at high temperature is thinner, which allows the coating to quickly pyrolyze and sublimate, so that the porous substrate at high temperature can be sweated and cooled in time, avoiding insufficient coolant flow supply due to vapor blockage effect;

[0041] 3. This invention can keep the interior of a porous matrix consistently filled with coolant from beginning to end. By setting an exposed area, the coolant first completely discharges the gas inside the porous matrix through the porous matrix, and the coolant continuously seeps out through the porous matrix and through the exposed area, forming a liquid film on the heated side of the porous matrix. When the flame comes into contact with the heated side of the porous matrix, the liquid film acts as an insulation, and allows the coolant inside the porous matrix to continuously seep out, keeping it in a state of being filled with coolant.

[0042] 4. The porous substrate of the present invention is not prone to overheating and heat loss because by setting an exposed area, the interior of the porous substrate is kept consistently filled with coolant from beginning to end. This avoids the situation where there is gas inside the porous substrate when the flame first impacts it. Since the specific heat capacity of gas is small and its heat absorption capacity is limited, when the external high temperature environment arrives, the coating and sweating cooling have not yet played their role, causing the porous plate to heat up rapidly, resulting in overheating and heat loss. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the sweating and cooling process of the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0045] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0046] This invention discloses a method for preparing a locally adaptive porous matrix combined with coating sublimation, comprising the following steps:

[0047] Step 1: Select coating materials based on the safe temperature of the porous substrate. The sublimation point temperature of the selected coating material should be ≤ the safe temperature of the porous substrate minus the predetermined temperature. The porous substrate can be a stainless steel porous plate, a nickel-based alloy porous plate, or a C / SiC composite porous plate. The safe temperature of the nickel-based alloy porous plate is 1000℃, the safe temperature of the C / SiC composite porous plate is 1650℃, and the safe temperature of the stainless steel porous plate is 600℃. The porosity of the porous substrate is 10%-40%, and the pore size is 5-100μm.

[0048] Step 2: Mix the various coating materials with the additives required during the spraying process to obtain a coating material mixture. Perform thermogravimetric analysis on the coating material mixture to obtain the weight loss and residual amount of each coating material mixture through experiments.

[0049] Step 3: Select a coating material mixture with a weight loss ratio ≥96% and a residual amount ≤4% under conditions above the sublimation temperature of the coating material. Apply this coating material mixture to the heated side of the porous substrate to obtain an adaptive porous substrate.

[0050] The heated surface of the porous substrate is divided into an exposed area and a coated area. The coated area surrounds the exposed area, which can be circular, square, or rectangular. A coating material mixture is applied to the coated area to completely seal the pores on the porous substrate except for the exposed area during sweating cooling, thereby preventing coolant leakage. The exposed area is the exposed heated surface of the porous substrate and is used to guide the coolant and concentrate its seepage from the exposed area.

[0051] As an example, in step 1, two coating materials can be selected, namely a first coating material and a second coating material. The predetermined temperature of the first coating material is 201-400℃, and the predetermined temperature of the second coating material is 100-200℃.

[0052] The first coating material is mixed with the additives required during the spraying process to obtain the first coating mixture, and the second coating material is mixed with the additives required during the spraying process to obtain the second coating mixture; the coating area is divided into a first coating area and a second coating area, the first coating area is close to the exposed area and extends outward in a ring with the exposed area as the center, and the second coating area is far from the exposed area and extends outward in a ring with the exposed area as the center and touches the first coating area; the first coating mixture is applied to the first coating area, and the second coating mixture is applied to the second coating area; the coating thickness of the first coating mixture is less than the coating thickness of the second coating mixture.

[0053] In this embodiment, the coating method for the coating area in step 3 is as follows:

[0054] The porous substrate is cleaned to remove impurities and then dried.

[0055] Labels are affixed to the exposed areas on the heated side of the porous substrate and to the first coating area.

[0056] The second coating mixture was repeatedly and evenly applied to the heated side of the porous substrate, and the label was removed and allowed to stand.

[0057] Labels are affixed to the exposed areas on the heated side of the porous substrate and to the second coating area.

[0058] The first coating mixture is repeatedly and evenly applied to the heated side of the porous substrate, and the label is removed and allowed to stand.

[0059] In another embodiment, only one coating material is selected in step 1. The predetermined temperature of the material is 201-400°C, and the thickness of the coating in the coating area is 50-200 μm. The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring with the exposed area as its center. The second coating area is far from the exposed area and extends outward in a ring with the exposed area as its center and is in contact with the first coating area. The coating thickness of the first coating area is less than the coating thickness of the second coating area.

[0060] In this embodiment, the coating method for the coating area in step 3 is as follows:

[0061] The porous substrate is cleaned to remove impurities and then dried.

[0062] Affix a label to the exposed area on the heated side of the porous substrate.

[0063] Apply the coating material mixture repeatedly and evenly to the heated side of the porous substrate, remove the label, and let it stand.

[0064] The present invention also discloses a locally adaptive porous substrate combined with coating sublimation, comprising: a porous substrate and an adaptive coating, wherein the heated side surface of the porous substrate is divided into an exposed area and a coated area, and the coated area is divided into a first coated area and a second coated area, wherein the first coated area is close to the exposed area and extends outward in a ring with the exposed area as the center, and the second coated area is far from the exposed area and extends outward in a ring with the exposed area as the center and is in contact with the first coated area.

[0065] An adaptive coating is applied to a first coating region and a second coating region of a porous substrate, wherein the coating thickness of the first coating region is less than the coating thickness of the second coating region, and the coating material mixture of the first coating region and the second coating region is the same.

[0066] The present invention also discloses a locally adaptive porous substrate combined with coating sublimation, comprising: a porous substrate, a first adaptive coating, and a second adaptive coating.

[0067] The heated side surface of the porous substrate is divided into an exposed area and a coated area. The coated area is further divided into a first coated area and a second coated area. The first coated area is close to the exposed area and extends outward in a ring shape with the exposed area as its center. The second coated area is far from the exposed area and extends outward in a ring shape with the exposed area as its center, and is in contact with the first coated area. A first adaptive coating is applied to the first coated area of ​​the porous substrate, and a second adaptive coating is applied to the second coated area of ​​the porous substrate. The coating materials of the first adaptive coating and the second adaptive coating are different, and the coating thickness of the first coated area is less than that of the second coated area.

[0068] The porous matrix of the present invention, such as Figure 1As shown, the heat flux density is highest at the center and gradually decreases towards the edge of the porous substrate. Therefore, the central part of the porous substrate is set as the exposed area, and the coolant is always kept in a state of flow. When a high heat flux environment arrives, it can be directly cooled. The first coating area undergoes ablation and sublimation under high heat flux conditions. When the coating of the first coating area is completely ablated, the sweating cooling at the corresponding position is activated, and the coolant concentrates to seep out from this area and the exposed area for sweating cooling.

[0069] In contrast, other areas with relatively low heat flux density, namely the second coating area, are not ablated or are completely ablated, and the temperature on the heated side will not exceed the pyrolysis temperature of the coating in the second coating area, so the porous substrate will not suffer heat loss; at the same time, the coating in the second coating area plays a role in heat insulation, providing another layer of thermal protection for the porous substrate.

[0070] Example 1

[0071] Step 1: Select coating materials based on the safe temperature of the porous substrate. The sublimation point temperature of the coating material is ≤ the safe temperature of the porous substrate - the predetermined temperature. The selected porous substrate is a nickel-based alloy porous plate with a safe temperature of 1000℃ and a pore size of 23.8μm. The selected predetermined temperature is 300℃.

[0072] Step 2: Mix each coating material with the additives required in the spraying process to obtain a coating material mixture. Perform thermogravimetric analysis on the coating material mixture to obtain the weight loss and residual amount of each coating material mixture through experiments.

[0073] Step 3: Select a coating material mixture with a weight loss ratio ≥96% and a residual amount ≤4% under conditions above the sublimation point temperature of the coating material.

[0074] The selected coating material is E40 epoxy resin. The required additives are: polyamide resin as a coagulant, acetone as a solvent and rheology thickener, waterborne polyurethane as a toughening agent, and red ink dye as a colorant. These are mixed to obtain the coating material mixture. Thermogravimetric analysis results show that at approximately 603℃, the coating material mixture experiences a weight loss of 96%, with a residual weight of 4%. Above 626℃, the weight loss exceeds 98%, with a residual weight of 2%.

[0075] The coating material mixture was applied to the heated side of the porous substrate to obtain an adaptive porous substrate with a coating thickness of 40 μm.

[0076] The coating method in step 3 is as follows:

[0077] Porous substrate surface pretreatment:

[0078] The surface of the porous substrate to be coated is cleaned with butyl acetate to dissolve and remove any oil or dust. Next, the entire porous substrate is immersed in an ultrasonic cleaner containing 95% alcohol at 30°C for 15 minutes to completely dissolve any remaining butyl acetate on the surface and to thoroughly dissolve any other impurities inside and on the surface of the porous substrate. Finally, the porous substrate is immersed in an ultrasonic cleaner containing distilled water at room temperature for 15 minutes. After removal, it is rinsed three times with distilled water to remove any remaining impurities or solutes. Finally, it is dried in a dryer at 150°C for one hour to remove any remaining moisture from the porous substrate. Finally, it is allowed to cool and stand for 3 hours to reach room temperature.

[0079] Preparation of coating material mixture:

[0080] The exposed area on the heated side of the porous substrate is circular with a diameter of 26 mm. The central area with a diameter of 5 mm corresponds to a high heat flux density region, which is designated as the exposed area. Based on the area and thickness of the required coating region, the total mass of the coating is calculated to be 20 g. Acetone solvent evaporates quickly and is not included in the calculation of the total coating mass. All other substances are effective cured products and ultimately exist in solid form.

[0081] Dissolve 8g of E40 epoxy resin and 2g of polyamide resin in acetone. Add 2.5g of waterborne polyurethane to the solution, and add an appropriate amount of acetone to adjust the viscosity of the slurry. Add 15g of red waterborne ink dye to the slurry to color the coating material and increase its visibility. Finally, put all the mixed slurries into a high-speed dispersion homogenizer and stir for 10 minutes at 4kr / min to prepare a uniform coating material mixture.

[0082] Preparation of porous substrate coating:

[0083] During the coating process, a circular white label with a diameter of 5 mm is attached to the exposed area on the heated side of the porous substrate to cover the exposed area. Then, the coating material mixture is repeatedly and evenly applied to the heated side of the porous substrate with a paint brush. Finally, the white label is removed with tweezers, and the coated porous substrate is placed at room temperature for 24 hours to allow the coating on the surface of the porous substrate to cure completely.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a locally adaptive porous matrix combined with coating sublimation, characterized in that, It consists of the following steps: Step 1: Select coating materials based on the safe temperature of the porous substrate. The sublimation point temperature of the selected coating material should be ≤ the safe temperature of the porous substrate - the predetermined temperature. Step 2: Mix the various coating materials with the additives required during the spraying process to obtain a coating material mixture. Perform thermogravimetric analysis on the coating material mixture to obtain the weight loss and residual amount of each coating material mixture through experiments. Step 3: Select a coating material mixture with a weight loss ratio ≥96% and a residual amount ≤4% under conditions higher than the sublimation temperature of the coating material. Apply this coating material mixture to the heated side of the porous substrate to obtain an adaptive porous substrate. The heated side surface of the porous substrate is divided into an exposed area and a coated area. The coated area is coated with a coating material mixture and is used to completely seal the pores on the porous substrate except for the exposed area during sweating and cooling, thereby preventing the leakage of coolant. The exposed area is the exposed heated side surface of the porous substrate and is used to guide the coolant and concentrate its seepage from the exposed area.

2. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 1, characterized in that, In step 1, two coating materials are selected, namely a first coating material and a second coating material. The predetermined temperature of the first coating material is 201-400℃, and the predetermined temperature of the second coating material is 100-200℃. The first coating material is mixed with the additives required in the spraying process to obtain a first coating mixture, and the second coating material is mixed with the additives required in the spraying process to obtain a second coating mixture; The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring with the exposed area as the center. The second coating area is far from the exposed area and extends outward in a ring with the exposed area as the center and touches the first coating area. The first coating mixture is applied to the first coating area, and the second coating mixture is applied to the second coating area; The coating thickness of the first coating mixture is less than that of the second coating mixture.

3. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 1, characterized in that, In step 1, a coating material is selected, the predetermined temperature of which is 201-400℃, and the thickness of the coating in the coating area is 50-200μm.

4. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 3, characterized in that, The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring with the exposed area as the center. The second coating area is far from the exposed area and extends outward in a ring with the exposed area as the center and touches the first coating area. The coating thickness of the first coating area is less than the coating thickness of the second coating area.

5. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 1, characterized in that, The coating area is arranged around the exposed area, and the exposed area is circular or square.

6. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 1, characterized in that, The porous substrate is a stainless steel porous plate, a nickel-based alloy porous plate, or a C / SiC composite porous plate. The safe temperature of the nickel-based alloy porous plate is 1000℃, the safe temperature of the C / SiC composite porous plate is 1650℃, and the safe temperature of the stainless steel porous plate is 600℃. The porosity of the porous substrate is 10%-40%, and the pore size is 5-100μm.

7. The method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 1, characterized in that, in, The coating method for the coating area in step 3 is as follows: The porous substrate is cleaned to remove impurities and then dried. Affix a label to the exposed area on the heated side of the porous substrate. Apply the coating material mixture repeatedly and evenly to the heated side of the porous substrate, remove the label, and let it stand.

8. A method for preparing a locally adaptive porous matrix combined with coating sublimation according to claim 2 or 4, characterized in that, in, The coating method for the coating area in step 3 is as follows: The porous substrate is cleaned to remove impurities and then dried. Labels are affixed to the exposed areas on the heated side of the porous substrate and to the first coating area. The second coating mixture was repeatedly and evenly applied to the heated side of the porous substrate, and the label was removed and allowed to stand. Labels are affixed to the exposed areas on the heated side of the porous substrate and to the second coating area. The first coating mixture is repeatedly and evenly applied to the heated side of the porous substrate, and the label is removed and allowed to stand.

9. A locally adaptive porous matrix with combined coating sublimation, prepared according to the preparation method of claim 1, characterized in that, The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring shape with the exposed area as its center. The second coating area is far from the exposed area and extends outward in a ring shape with the exposed area as its center, and is in contact with the first coating area. An adaptive coating is applied to a first coating region and a second coating region of a porous substrate, wherein the coating thickness in the first coating region is less than the coating thickness in the second coating region. The coating material mixtures in the first coating area and the second coating area are the same.

10. A locally adaptive porous matrix incorporating coating sublimation, Prepared according to the preparation method of claim 1, characterized in that, The coating area is divided into a first coating area and a second coating area. The first coating area is close to the exposed area and extends outward in a ring shape with the exposed area as its center. The second coating area is far from the exposed area and extends outward in a ring shape with the exposed area as its center, and is in contact with the first coating area. The first adaptive coating is applied to the first coating area of ​​the porous substrate. The second adaptive coating is applied to the second coating area of ​​the porous substrate. The coating materials of the first adaptive coating and the second adaptive coating are different, and the coating thickness of the first coating area is less than that of the second coating area.

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