Processing method of high temperature protective coating on high temperature alloy of aircraft engine

Abstract

The invention discloses a processing method of a high-temperature protective coating on an aero-engine high-temperature alloy. First, a substrate surface is ground and polished; then a cold spray gun is used to preheat the substrate; then at least one layer of MCrAlY is cold-sprayed on the substrate surface by the cold spray gun using helium as a carrier gas to form an MCrAlY primer coating; then multiple layers of MCrAlY are cold-sprayed on the substrate surface by the cold spray gun using nitrogen as a carrier gas; finally, the MCrAlY primer coating on the substrate surface and the MCrAlY outer surface coating are vacuum-heat-treated. In this scheme, helium and nitrogen are used as carrier gases to spray MCrAlY in sequence to form an MCrAlY primer coating and an MCrAlY outer surface coating on the substrate surface in sequence, so as to simultaneously ensure that the bonding strength between the MCrAlY coating and the substrate is high, the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of a counterpart, and the performance and service life of the substrate are improved to meet the use requirements in actual application processes.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engine alloy processing technology, and in particular to a processing method for a high-temperature protective coating on an aircraft engine high-temperature alloy. Background Art

[0002] High-temperature alloys are widely used in high-temperature components in gas turbines and aircraft engines due to their high operating temperature, high yield strength and good high-temperature creep performance. Their service conditions are harsh and they are usually faced with multiple influences such as high temperature (temperature of 600-1200°C), friction, oxidation, gas corrosion and complex stress (creep, high and low cycle fatigue, thermal fatigue, etc.). In addition, due to the high cost of raw materials, complex preparation process and long process, they are expensive. Therefore, the surface of high-temperature alloys usually needs to be coated with high-temperature protective coating to improve the performance and service life of high-temperature alloys.

[0003] Since MCrAlY (M represents Co and / or Ni) has good resistance to high-temperature oxidation and corrosion, the existing high-temperature protective coating on the surface of high-temperature alloys usually uses a cold spray gun to spray MCrAlY on the surface of the high-temperature alloy substrate to form a high-temperature protective coating. The MCrAlY coating can form a dense Cr2O3 and Al2O3 oxide film on the surface under high temperature conditions, which can prevent oxygen elements from diffusing into the interior, thereby improving the high-temperature oxidation resistance and corrosion resistance of the substrate. However, the existing MCrAlY coating often has the following problems during processing: 1. In order to ensure the bonding strength between the MCrAlY coating and the substrate, the surface high-temperature hardness and wear resistance of the MCrAlY coating are too high, even exceeding the surface high-temperature hardness and wear resistance of the counterpart, which easily causes wear on the counterpart; 2. In order to ensure that the surface high-temperature hardness and wear resistance of the MCrAlY coating are not higher than that of the counterpart, the bonding strength between the MCrAlY coating and the substrate is too low, and the MCrAlY coating is easy to fall off, which does not meet the requirements of improving the sufficient performance and service life of the high-temperature alloy. Summary of the invention

[0004] The present invention provides a method for processing a high-temperature protective coating on an aircraft engine high-temperature alloy, so as to solve the technical problems that the existing method for processing a high-temperature protective coating on an aircraft engine high-temperature alloy cannot simultaneously ensure that the bonding strength between the MCrAlY coating and the substrate is high and the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart.

[0005] According to one aspect of the present invention, a method for processing a high-temperature protective coating on a high-temperature alloy of an aircraft engine is provided, comprising the following steps: a. grinding and polishing the surface of a substrate; b. preheating the substrate using a cold spray gun; c. using the cold spray gun to cold spray at least one layer of MCrAlY on the surface of the substrate using helium as a carrier gas to form an MCrAlY primer coating; d. using the cold spray gun to cold spray multiple layers of MCrAlY on the surface of the substrate using nitrogen as a carrier gas to form an MCrAlY outer surface coating with a preset thickness; and e. vacuum heat treatment of the MCrAlY primer coating and the MCrAlY outer surface coating on the surface of the substrate.

[0006] Furthermore, in step b, the preheating temperature of the substrate is in the range of 200-600°C.

[0007] Further, in step c, the operating temperature range of helium is 300-1000° C., and the operating pressure of helium is 1-4 MPa.

[0008] Further, in step d, the working temperature range of nitrogen is 500-1000° C., and the working pressure of nitrogen is 2-7 MPa.

[0009] Furthermore, in step e, the vacuum degree of the vacuum heat treatment is not less than 10 -4 Pa, the heat treatment temperature range of vacuum heat treatment is 850-1200℃, and the heat treatment time range of vacuum heat treatment is 2-8h.

[0010] Furthermore, the particle size distribution range of the MCrAlY alloy powder is 5-100 μm.

[0011] Further, in step c, the range of the moving speed of the cold spray gun is 10-1000 mm / s; and / or in step d, the range of the moving speed of the cold spray gun is 10-1000 mm / s.

[0012] Furthermore, the substrate is a nickel-based high-temperature alloy GH625, the preheating temperature is 400°C, the working temperature of helium is 700°C, the number of spray layers of the MCrAlY primer coating is 1, the working temperature of nitrogen is 900°C, the number of spray layers of the MCrAlY outer surface coating is 10, the gun travel speed of the cold spray gun is 200mm / s, the heat treatment temperature of the vacuum heat treatment is 1080°C, and the heat treatment time of the vacuum heat treatment is 4h.

[0013] Furthermore, the interface bonding strength between the sprayed MCrAlY coating and the substrate exceeds 125 MPa, and the high temperature hardness of the surface at 1000°C is 165±20 Hv.

[0014] Furthermore, step a also includes: cleaning and wiping the surface of the substrate.

[0015] The present invention has the following beneficial effects:

[0016] The processing method of the high-temperature protective coating on the aircraft engine high-temperature alloy of the present invention comprises the following steps: firstly grinding and polishing the substrate surface to remove the oxide layer on the substrate surface for the convenience of the subsequent spraying work; then preheating the substrate by using a cold spray gun, so that when spraying MCrAlY, the substrate surface temperature is adapted to the spraying temperature to avoid thermal stress deformation caused by overheating of the substrate; secondly, the plastic deformation capacity of the substrate can be improved by pretreating the substrate, thereby improving the bonding strength between the coating and the substrate; then cold spraying at least one layer of MCrAlY on the substrate surface by using helium as a carrier gas by using a cold spray gun to form an MCrAlY primer coating; since the molecular weight of helium is relatively small, the effect of accelerating MCrAlY particles is good, so that the density of the MCrAlY primer coating is high, and thus the bonding strength between the MCrAlY primer coating and the substrate is high; next, cold spraying multiple layers of MCrAlY on the substrate surface by using nitrogen as a carrier gas by using a cold spray gun to form an MCrAlY outer surface coating with a preset thickness; since nitrogen accelerates MCrAlY particles, the MCrAlY primer coating is formed on the substrate surface; The effect of MCrAlY particles is much lower than that of helium. Therefore, the density and hardness of the MCrAlY outer surface coating are relatively low, ensuring that the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart. At the same time, since the MCrAlY outer surface coating has a preset thickness, it can withstand long-term wear and further improve the service life of the substrate. Finally, the MCrAlY primer coating and the MCrAlY outer surface coating on the substrate surface are vacuum heat treated to form dense Cr2O3 and Al2O3 oxide films to improve the high-temperature oxidation resistance and corrosion resistance of the substrate. In this scheme, helium and nitrogen are used as carrier gases to spray MCrAlY in sequence to form an MCrAlY primer coating and an MCrAlY outer surface coating on the substrate surface in sequence, so as to simultaneously ensure that the bonding strength between the MCrAlY coating and the substrate is high and the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart, and the performance and service life of the substrate are improved to meet the use requirements in actual applications.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1It is a flowchart of the steps of a method for processing a high temperature protective coating on an aerospace engine high temperature alloy according to a preferred embodiment of the present invention;

[0020] Figure 2 This is a SEM image of the cold sprayed powder of MCrAlY in the method for processing a high temperature protective coating on an aircraft engine high temperature alloy according to a preferred embodiment of the present invention;

[0021] Figure 3 This is a SEM cross-sectional view of a cold-sprayed MCrAlY primer coating prepared under 700°C and He conditions according to a processing method for a high-temperature protective coating on an aero-engine high-temperature alloy in a preferred embodiment of the present invention;

[0022] Figure 4 It is a SEM cross-sectional view of a cold-sprayed MCrAlY outer layer coating prepared under 900°C and N2 conditions in a processing method for a high-temperature protective coating on an aero-engine high-temperature alloy according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0024] Figure 1 It is a flowchart of the steps of a method for processing a high temperature protective coating on an aerospace engine high temperature alloy according to a preferred embodiment of the present invention;

[0025] Figure 2 This is a SEM image of the cold sprayed powder of MCrAlY in the method for processing a high temperature protective coating on an aircraft engine high temperature alloy according to a preferred embodiment of the present invention; Figure 3 This is a SEM cross-sectional view of a cold-sprayed MCrAlY primer coating prepared under 700°C and He conditions according to a processing method for a high-temperature protective coating on an aero-engine high-temperature alloy in a preferred embodiment of the present invention; Figure 4 It is a SEM cross-sectional view of a cold-sprayed MCrAlY outer layer coating prepared under 900°C and N2 conditions in a processing method for a high-temperature protective coating on an aero-engine high-temperature alloy according to a preferred embodiment of the present invention.

[0026] like Figure 1-Figure 4As shown, the processing method of the high temperature protective coating on the aircraft engine high temperature alloy of this embodiment includes the following steps: a. grinding and polishing the substrate surface; b. preheating the substrate with a cold spray gun; c. using helium as a carrier gas to cold spray at least one layer of MCrAlY on the substrate surface to form an MCrAlY primer coating; d. using nitrogen as a carrier gas to cold spray multiple layers of MCrAlY on the substrate surface to form an MCrAlY outer surface coating with a preset thickness; e. vacuum heat treatment of the MCrAlY primer coating and the MCrAlY outer surface coating on the substrate surface. Specifically,

[0027] The processing method of the high-temperature protective coating on the aircraft engine high-temperature alloy of the present invention comprises the following steps: firstly grinding and polishing the substrate surface to remove the oxide layer on the substrate surface for the convenience of the subsequent spraying work; then preheating the substrate by using a cold spray gun, so that when spraying MCrAlY, the substrate surface temperature is adapted to the spraying temperature to avoid thermal stress deformation caused by overheating of the substrate; secondly, the plastic deformation capacity of the substrate can be improved by pretreating the substrate, thereby improving the bonding strength between the coating and the substrate; then cold spraying at least one layer of MCrAlY on the substrate surface by using helium as a carrier gas by using a cold spray gun to form an MCrAlY primer coating; since the molecular weight of helium is relatively small, the effect of accelerating MCrAlY particles is good, so that the density of the MCrAlY primer coating is high, and thus the bonding strength between the MCrAlY primer coating and the substrate is high; next, cold spraying multiple layers of MCrAlY on the substrate surface by using nitrogen as a carrier gas by using a cold spray gun to form an MCrAlY outer surface coating with a preset thickness; since nitrogen accelerates MCrAlY particles, the MCrAlY primer coating is formed on the substrate surface; The effect of MCrAlY particles is much lower than that of helium. Therefore, the density and hardness of the MCrAlY outer surface coating are relatively low, ensuring that the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart. At the same time, since the MCrAlY outer surface coating has a preset thickness, it can withstand long-term wear and further improve the service life of the substrate. Finally, the MCrAlY primer coating and the MCrAlY outer surface coating on the substrate surface are vacuum heat treated to form dense Cr2O3 and Al2O3 oxide films to improve the high-temperature oxidation resistance and corrosion resistance of the substrate. In this scheme, helium and nitrogen are used as carrier gases to spray MCrAlY in sequence to form an MCrAlY primer coating and an MCrAlY outer surface coating on the substrate surface in sequence, so as to simultaneously ensure that the bonding strength between the MCrAlY coating and the substrate is high and the surface high-temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart, and the performance and service life of the substrate are improved to meet the use requirements in actual applications.

[0028] like Figure 1As shown, in this embodiment, in step b, the preheating temperature range of the substrate is 200-600°C. Specifically, when the preheating temperature of the substrate is between 200-600°C, when spraying MCrAlY, the substrate surface temperature is adapted to the spraying temperature, avoiding overheating of the substrate and thermal stress deformation, and the heating time and energy consumption are appropriate; when the preheating temperature of the substrate is less than 200°C, when spraying MCrAlY, the substrate surface temperature is too low, and the temperature difference with the impacted powder particles is large, which increases the internal stress of the coating, and the bonding strength between the coating and the substrate is low; when the preheating temperature of the substrate is greater than 600°C, it is easy to cause a large deformation of the substrate, and the heating time is too long, the energy consumption is too high, and the substrate surface is easily oxidized, which is not conducive to the deposition of the MCrAlY coating.

[0029] like Figure 1 As shown, in this embodiment, in step c, the working temperature range of helium is 300-1000°C, and the working pressure of helium is 1-4MPa. Specifically, when the working temperature of helium is between 300-1000°C, and the working pressure of helium is between 1-4MPa, the acceleration effect on MCrAlY particles is appropriate; when the working temperature of helium is less than 300 degrees Celsius, or the working pressure of helium is less than 1MPa, the acceleration effect on MCrAlY particles is poor, resulting in low density of MCrAlY primer coating, and thus the high bonding strength between MCrAlY coating and substrate cannot be guaranteed; when the working pressure of helium is greater than 4MPa, the acceleration effect on MCrAlY particles is strong, which is easy to cause damage to the substrate, thereby causing the performance of the substrate to deteriorate. It should be understood that when the working temperature of helium is higher than 1000°C, it is easy to cause severe oxidation of the powder, and the cold spray gun cannot meet the heat resistance requirements, thereby making it impossible to perform cold spraying.

[0030] like Figure 1As shown, in this embodiment, in step d, the working temperature range of nitrogen is 500-1000°C, and the working pressure of nitrogen is 2-7MPa. Specifically, when the working temperature of nitrogen is between 500-1000°C, and the working pressure of nitrogen is between 2-7MPa, the acceleration effect on MCrAlY particles is appropriate; when the working temperature of nitrogen is less than 500°C, or the working pressure of nitrogen is less than 2MPa, the acceleration effect on MCrAlY particles is poor, resulting in too low density of MCrAlY outer surface coating, and the MCrAlY outer surface coating is very easy to wear, thereby failing to increase the sufficient service life of the substrate; when the working pressure of nitrogen is greater than 7MPa, the acceleration effect on MCrAlY particles is too strong, resulting in too high density of MCrAlY outer surface coating, thereby failing to ensure that the surface high temperature hardness and wear resistance of MCrAlY coating are lower than the surface high temperature hardness and wear resistance of the counterpart, thereby easily causing wear of the counterpart. It should be understood that when the working temperature of nitrogen is higher than 1000°C, it is easy to cause severe oxidation of the powder, and the cold spray gun cannot meet the heat resistance requirements, which makes cold spraying impossible.

[0031] like Figure 1 As shown, in this embodiment, in step e, the vacuum degree of vacuum heat treatment is not less than 10 -4 Pa, the heat treatment temperature range of vacuum heat treatment is 850-1200℃, and the heat treatment time range of vacuum heat treatment is 2-8h. Specifically, when the heat treatment temperature of vacuum heat treatment is between 850-1200℃, the diffusion rate of MCrAlY coating is appropriate, which effectively improves the performance and service life of the substrate; when the heat treatment temperature of vacuum heat treatment is lower than 850℃, the diffusion rate of MCrAlY coating is too slow or even unable to form a diffusion layer, resulting in uneven distribution of crystal structure on the surface of the substrate and strength defects in local areas of the substrate; when the heat treatment temperature of vacuum heat treatment is higher than 1200℃, it will affect the heat treatment state of the substrate and damage the MCrAlY coating, and will not be able to improve the performance and service life of the substrate. It should be understood that the vacuum degree of vacuum heat treatment must be no less than 10 - 4 Pa, can avoid oxidation reaction on the substrate surface during vacuum heat treatment; and the heat treatment temperature of vacuum heat treatment is inversely proportional to the heat treatment time of vacuum heat treatment, that is, the higher the heat treatment temperature of vacuum heat treatment, the shorter the heat treatment time of vacuum heat treatment; that is, the lower the heat treatment temperature of vacuum heat treatment, the longer the heat treatment time of vacuum heat treatment.

[0032] In this embodiment, the particle size distribution range of the MCrAlY alloy powder is 5-100 μm. It should be understood that when the particle size distribution of the MCrAlY alloy powder is between 5-100 μm, the MCrAlY particles are easily combined with the crystal structure on the surface of the substrate, and the density of the MCrAlY coating is ensured, thereby ensuring that the bonding strength between the MCrAlY coating and the substrate is high, and the material cost is appropriate; when the particle size distribution of the MCrAlY alloy powder is less than 5 μm, the preparation of the MCrAlY alloy powder is difficult, and the material cost is too high; when the particle size distribution of the MCrAlY alloy powder is greater than 100 μm; the MCrAlY particles are difficult to combine with the crystal structure on the surface of the substrate. The density of the MCrAlY coating cannot be ensured, and the bonding strength between the MCrAlY coating and the substrate cannot be ensured.

[0033] like Figure 1 As shown, in this embodiment, in step c, the range of the cold spray gun speed is 10-1000 mm / s; and / or in step d, the range of the cold spray gun speed is 10-1000 mm / s. Specifically, when the cold spray gun speed is between 10-1000 mm / s, the MCrAlY coating can be guaranteed to have an appropriate thickness and density; when the cold spray gun speed is lower than 10 mm / s, the deposition rate of the MCrAlY coating is too fast, resulting in increased stress in the coating, and easily causing the substrate temperature to be too high, resulting in severe deformation; when the cold spray gun speed is higher than 1000 mm / s, the deposition rate of the MCrAlY coating is too slow, and the production efficiency is low.

[0034] like Figure 1-Figure 4As shown, in this embodiment, the substrate is a nickel-based high-temperature alloy GH625, the preheating temperature is 400°C, the working temperature of helium is 700°C, the number of spray layers of the MCrAlY primer coating is 1, the working temperature of nitrogen is 900°C, the number of spray layers of the MCrAlY outer surface coating is 10, the gun travel speed of the cold spray gun is 200mm / s, the heat treatment temperature of the vacuum heat treatment is 1080°C, and the heat treatment time of the vacuum heat treatment is 4h. Specifically, when the substrate is a nickel-based high alloy GH625, in step b, the preheating temperature is selected to be 400°C, in step c, the working temperature of helium is selected to be 700°C, the number of spray layers of MCrAlY primer coating is 1, and the travel speed of the cold spray gun is 200mm / s, in step d, the working temperature of nitrogen is selected to be 900°C, the number of spray layers of MCrAlY outer surface coating is 10, and the travel speed of the cold spray gun is 200mm / s, in step e, the heat treatment temperature of vacuum heat treatment is selected to be 1080°C, and the heat treatment time of vacuum heat treatment is selected to be 4h, so as to obtain a processed substrate that can simultaneously ensure that the interface bonding strength between the MCrAlY coating and the substrate is high and the surface high temperature hardness and wear resistance of the MCrAlY coating are lower than the surface high temperature hardness and wear resistance of the counterpart. It should be understood that, if Figure 3 As shown in FIG. 1 , the MCrAlY primer coating prepared by using helium at a working temperature of 700°C is fine and uniform, and has good performance. Figure 4 As shown, the MCrAlY outer surface coating prepared at a working temperature of 900°C using nitrogen is fine and uniform, and has good performance. It should be understood that due to the high cost of helium, using helium to spray only one layer of MCrAlY can reduce costs while meeting design requirements. It should be understood that in a control experiment, if steps a, b, c, and e in the above embodiment are adopted, and the number of spray layers of the MCrAlY primer coating in step c is changed to 10 layers, and the interface bonding strength between the MCrAlY coating and the high-temperature alloy substrate exceeds 125MPa, the bonding strength between the MCrAlY coating and the substrate can be ensured to be high, but the high-temperature hardness of the surface at 1000°C is 190±20Hv, so that the surface high-temperature hardness and wear resistance of the MCrAlY coating are higher than the surface high-temperature hardness and wear resistance of the counterpart, which is easy to cause wear of the counterpart. It should be understood that, in a control experiment, if steps a, b, d, and e in the above embodiment are adopted, the interface bonding strength between the MCrAlY coating and the high-temperature alloy substrate is 56 MPa, and the high-temperature hardness of the surface at 1000°C is 165±20 Hv, that is, the surface high-temperature hardness and wear resistance of the MCrAlY coating can be ensured to be lower than the surface high-temperature hardness and wear resistance of the counterpart, but the bonding strength between the MCrAlY coating and the substrate cannot be guaranteed.

[0035] In this embodiment, the interface bonding strength between the sprayed MCrAlY coating and the substrate exceeds 125MPa, and the high temperature hardness of the surface at 1000°C is 165±20Hv. Specifically, when the interface bonding strength between the MCrAlY coating and the substrate exceeds 125MPa, the interface bonding strength between the MCrAlY coating and the substrate is high, and when the high temperature hardness of the surface at 1000°C is 165±20Hv, the surface high temperature hardness and wear resistance of the MCrAlY coating are lower than those of the counterpart. It should be understood that the MCrAlY powder particles can be observed by a scanning electron microscope; the thickness of the MCrAlY coating can be measured by a vernier caliper or under a scanning electron microscope; and the bonding strength of the MCrAlY coating can be measured by a tensile test.

[0036] In this embodiment, step a further comprises: cleaning and wiping the surface of the substrate. Specifically, after sandpaper is used to grind and polish the surface of the substrate to remove the oxide layer, the substrate is cleaned with alcohol and then wiped clean with a rag. Optionally, the cleaning method is ultrasonic cleaning.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for processing a high temperature protective coating on an aircraft engine high temperature alloy, characterized in that: The following steps are involved: a. Grinding and polishing the substrate surface; b. Use a cold spray gun to preheat the substrate; c. Using helium as carrier gas, a cold spray gun cold sprays a layer of MCrAlY on the surface of the substrate to form an MCrAlY primer coating; d. using a cold spray gun to cold spray 10 layers of MCrAlY on the surface of the substrate using nitrogen as a carrier gas to form an MCrAlY outer surface coating with a preset thickness; e. vacuum heat treatment of the MCrAlY primer coating on the substrate surface and the MCrAlY outer surface coating; The substrate is a nickel-based high-temperature alloy GH625, the preheating temperature is 400°C, the working temperature of helium is 700°C, the working temperature of nitrogen is 900°C, the travel speed of the cold spray gun is 200mm / s, the heat treatment temperature of vacuum heat treatment is 1080°C, and the heat treatment time of vacuum heat treatment is 4h; In step c, the working pressure of helium is 1-4 MPa; In step d, the working pressure of nitrogen is 2-7 MPa.

2. The method for processing high temperature protective coating on high temperature alloy of aircraft engine according to claim 1, characterized in that: In step e, the vacuum degree of the vacuum heat treatment is not less than 10 -4 Pa.

3. The method for processing high temperature protective coating on high temperature alloy of aircraft engine according to claim 1, characterized in that: The particle size distribution range of the MCrAlY alloy powder is 5-100 μm.

4. The method for processing a high temperature protective coating on an aircraft engine high temperature alloy according to any one of claims 1 to 3, characterized in that: The interface bonding strength between the sprayed MCrAlY coating and the substrate exceeds 125MPa, and the high temperature hardness of the surface at 1000℃ is 165±20Hv.

5. The method for processing a high temperature protective coating on an aircraft engine high temperature alloy according to any one of claims 1 to 3, characterized in that: Step a also includes: cleaning and wiping the surface of the substrate.

Images