High-temperature oxidation-resistant metal-based composite material coating and preparation method thereof

Abstract

The invention discloses a high-temperature oxidation-resistant metal-based composite material coating and a preparation method thereof. The high-temperature oxidation-resistant metal-based composite material coating comprises a metal matrix and an oxide strengthening phase distributed in the metal matrix, the metal matrix is a nickel-based medium-entropy alloy and comprises the following chemical components in percentage by mass: 20 to 30 percent of Co, 19 to 30 percent of Cr, 8 to 12 percent of Al, 3.5 to 5 percent of Ta, 0.3 to 1.5 percent of Y, less than 0.02 percent of impurities (C, S and O) in total and the balance of Ni, and the metal matrix comprises the following elements in percentage by mass: 20 to 30 percent of Co, 19 to 30 percent of Cr, 8 to 12 percent of Al, 3.5 to 5 percent of Ta, 0.3 to 1.5 percent of Y, less than 0.02 percent of impurities (C, S and O) and the balance of Ni; the oxide strengthening phase comprises at least one of Y2O3, ZrO2 or Al 2O3; the coating disclosed by the invention has a more compact microstructure, and the coating has higher strength and associativity; the coating has better high-temperature oxidation resistance, and the service life of the coating is effectively prolonged; according to the additive manufacturing method used in the invention, a compact high-temperature oxidation-resistant metal-based composite material coating is successfully prepared, and after heat treatment, a compact and complete aluminum oxide layer can be quickly formed in the initial stage of oxidation, so that the coating is protected from being oxidized; and the method is not limited by the surface shape of the base material and is easy to manufacture the structured coating.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature resistant and antioxidant coating materials, and particularly to a metal matrix composite coating with high-temperature oxidation resistance and a preparation method thereof. Background Art

[0002] There is a thermal barrier coating on the surface of hot-end components of gas turbines and aeroengines. It consists of a ceramic top layer and a bond coat, providing thermal insulation and antioxidant protection for the superalloy substrate. When the components serve in a high-temperature environment, oxygen permeates through the ceramic layer, and a thermally grown oxide layer will form between the bond coat and the ceramic layer interface. The denseness and integrity of this oxide layer are the key to protecting the superalloy substrate from oxidation erosion.

[0003] One of the important reasons for the high operation and maintenance costs of existing gas turbine hot-end components is that the substrate of the hot-end components is damaged due to the failure and shedding of the coating, resulting in a low service life of the hot-end components. Research shows that one of the main reasons for coating failure is the damage of the integrity of the thermally grown oxide layer, the reduction of antioxidant performance, and the weakening of the interfacial bonding strength between it and the bond coat and the ceramic layer. Therefore, the dynamic growth process and state of the thermally grown oxide layer are related to the performance and life of the entire thermal barrier coating system, and determine the service life of the hot-end components.

[0004] The thermally grown oxide layer is the product of the oxidation of the surface layer of the bond coat material. Its dynamic growth process is closely related to the composition and microstructure of the bond coat material. The existing manufacturing method of the bond coat is thermal spraying methods such as plasma spraying. On the one hand, its antioxidant performance is acceptable. On the other hand, the bonding strength between the bond coat metal and the substrate needs to be tested by ASTM C633-13(2021) to determine whether the film bonding strength is qualified; on this basis, the higher the tensile strength of the bond coat metal material, the more capable it is of withstanding load stress. Practical application experience data shows that the room-temperature tensile strength level of the thermally sprayed bond coat metal is only about 100-200 MPa.

[0005] Therefore, improving the current bond coat, enhancing its antioxidant performance and adhesion to the superalloy substrate, enabling it to have a longer service life, and reducing the maintenance cost of the hot-end components are of great significance for the long-term normal operation of gas turbines and ensuring power and power supply.

[0006] In summary, a metal matrix composite coating with high-temperature oxidation resistance and a preparation method thereof are proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide a metal matrix composite coating with high-temperature oxidation resistance and a preparation method thereof to solve the problems in the prior art.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A metal matrix composite coating with high temperature oxidation resistance, comprising a metal matrix and oxide strengthening phases distributed in the metal matrix;

[0010] The metal matrix is a nickel-based medium entropy alloy, and its chemical components are Ni, Co, Cr, Al, Ta and Y. The mass content of each element is as follows: Co: 20%-30%, Cr: 19%-30%, Al: 8%-12%, Ta: 3.5%-5%, Y: 0.3%-1.5%, and the sum of the contents of impurities (C, S, O) is less than 0.02%, and the balance is Ni;

[0011] The oxide strengthening phase includes at least one of Y2O3, ZrO2 or Al2O3.

[0012] In a preferred embodiment, the oxide strengthening phase is nano-sized oxide particles, and the particle size of the nano-sized oxide particles is 2-200 nm.

[0013] In a preferred embodiment, the particle size of the nano-sized oxide particles is 5-20 nm.

[0014] In a preferred embodiment, the mass percentage of the oxide strengthening phase in the metal matrix composite coating is 0%-5%.

[0015] In a preferred embodiment, the mass percentage of the oxide strengthening phase in the metal matrix composite coating is 0% or 0.4% or 0.6% or 0.8%.

[0016] In a preferred embodiment, the thickness of the metal matrix composite coating is controlled within 1-5 mm.

[0017] In a preferred embodiment, the thickness of the metal matrix composite coating is controlled within 2-3 mm.

[0018] In addition, the present application also provides a preparation method for a metal matrix composite coating with high temperature oxidation resistance, comprising the following steps:

[0019] S1, pretreatment of nano-sized particles, cleaning, activating, plating and post-treatment of nano-sized particles;

[0020] S2, preparation of nano-particle reinforced composite spherical powder. Pure substance particles or master alloy particles of Ni, Co, Cr, Al, Ta, Y, pretreated nano-sized particles and a dispersant are subjected to mechanical alloying in a high-energy ball mill under a protective atmosphere to obtain non-spherical micron-sized powder, and then this non-spherical micron-sized powder is spheroidized by plasma;

[0021] S3. Prepare the coating by additive manufacturing. Screen the prepared spherical powder of the nanoparticle-reinforced composite material to obtain the powder for preparing the additive manufacturing coating, and use the powder bed fusion or directed energy deposition process to prepare the additive coating;

[0022] S4. Prepare the coating by heat treatment. Perform two heat treatments on the prepared coating, namely, hold at 1080 °C for 4 hours and hold at 870 °C for 20 hours.

[0023] In a preferred embodiment, the technical indexes of the powder prepared by the powder bed fusion process are as follows:

[0024] Particle size D10 = 20 ± 5 um, D50 = 25 ± 5 um, D90 = 50 ± 5 um; Flowability (Hall flow rate) < 25 s / 50 g; Oxygen content < 500 ppm.

[0025] In a preferred embodiment, the technical indexes of the powder prepared by the directed energy deposition process are as follows:

[0026] Particle size D10 = 50 ± 5 um, D50 = 70 ± 5 um, D90 = 100 ± 5 um; Flowability (Hall flow rate) < 25 s / 50 g; Oxygen content < 500 ppm.

[0027] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0028] A high-temperature oxidation-resistant metal matrix composite coating and its preparation method provided by this application. The high-temperature oxidation-resistant metal matrix composite coating prepared by additive manufacturing has a denser microstructure, and the coating has higher strength and bonding properties; The method of adding nanoscale oxides by metal alloying enables the nanoscale oxides to act uniformly inside the metal matrix, making the heat treatment more refined and dispersed, reducing the growth rate of the thermally grown oxide layer, having better high-temperature oxidation resistance, and effectively extending the service life of the coating; The additive manufacturing methods used in this application, including powder bed fusion and directed energy deposition, successfully prepare a dense high-temperature oxidation-resistant metal matrix composite coating. After heat treatment, it is beneficial to quickly form a dense and complete alumina layer in the initial stage of oxidation, further protecting the coating from oxidation; The coating is prepared on the high-temperature alloy substrate of the hot-end component through additive manufacturing, which is not limited by the surface shape of the substrate and is easy to realize the manufacturing of structured coatings. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required for the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0030] Figure 1 It is the process flow chart for preparing the high-temperature oxidation-resistant metal matrix composite coating of the present invention;

[0031] Figure 2 It is a schematic diagram showing the variation law of oxidation weight gain and oxidation rate of the additive manufacturing and sprayed coating of the present invention with time;

[0032] Figure 3 It is a schematic diagram of the microstructure of the coating after heat treatment of the present invention;

[0033] Figure 4 It is a schematic diagram showing the variation law of the microstructure of the coating with different oxide contents and the TGO thickness at 1000 °C with time of the present invention;

[0034] Figure 5 It is for the present invention containing 1% Y 2 O 3 Schematic diagram of the room temperature tensile strength (engineering stress-strain curve) of the coating. Specific embodiments

[0035] In order to enable those skilled in the art of the present technology to better understand the solutions of this application, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of this application.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of this application described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] In this application, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0038] Moreover, in addition to being used to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the terms "mounted", "arranged", "provided with", "connected", "linked", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there is internal communication between two devices, elements or components. 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.

[0040] It should be noted that, without conflict, the embodiments and features in the embodiments of this application can be combined with each other. The following will refer to the drawings and combine with embodiments to detail this application.

[0041] Embodiment 1

[0042] This application provides a metal matrix composite coating with high-temperature oxidation resistance, including a metal matrix and oxide strengthening phases distributed in the metal matrix; the thickness of the metal matrix composite coating is controlled within 1 - 5 mm; more specifically, the thickness of the metal matrix composite coating is controlled within 2 - 3 mm;

[0043] The metal matrix is a nickel-based medium-entropy alloy, and its chemical components are Ni, Co, Cr, Al, Ta, and Y. The mass content of each element is as follows: Co: 20% - 30%, Cr: 19% - 30%, Al: 8% - 12%, Ta: 3.5% - 5%, Y: 0.3% - 1.5%, the sum of the contents of impurities (C, S, O) is less than 0.02%, and Ni: the balance;

[0044] The oxide strengthening phase includes at least one of Y2O3, ZrO2 or Al2O3; the oxide strengthening phase is nano-sized oxide particles, and the particle size of the nano-sized oxide particles is 2-200 nm. Further, the particle size of the nano-sized oxide particles is 5-20 nm; the mass percentage of the oxide strengthening phase in the metal matrix composite coating is 0%-5%, specifically 0% or 0.4% or 0.6% or 0.8% or 1%.

[0045] Example 2

[0046] The chemical composition of the metal matrix composite coating includes: 22-24% of Co, 19-21% of Cr, 8-9% of Al, 3.5-4.5% of Ta, 0.3-0.9% of Y, and the sum of the contents of impurities (C, S, O) is less than 0.02%. In this example, by weight percentage, the chemical composition of the metal matrix includes: 23% of Co, 20% of Cr, 8.5% of Al, 4% of Ta, 0.6% of Y, and the sum of the contents of impurities (C, S, O) is less than 0.02%, and the balance is Ni.

[0047] Compared with the coating prepared by the traditional spraying method, the mass per unit area of the coating prepared by the spraying method increases by about 23.0 g / m2 after oxidation at 1000 °C for 120 hours, and the thickness of the oxide layer is 2.417 μm; while the mass per unit area of the additive manufacturing coating of the present invention increases by about 10.0 g / m2 after oxidation at 1000 °C for 120 hours, and the thickness of the oxide layer is 2.023 μm. The coating in this application has stronger oxidation resistance, and the test results are shown in the appendix Figure 2 。

[0048] Example 3

[0049] As Figure 3 shown, the microstructure of the high-temperature oxidation-resistant metal matrix composite coating after heat treatment under different additive manufacturing methods. Further, the heat treatment method in this example is specifically DED and PBF.

[0050] Further, by weight percentage, the chemical composition of the metal matrix of the coating includes: 22-24% of Co, 19-21% of Cr, 8-9% of Al, 3.5-4.5% of Ta, 0.3-0.9% of Y, and the sum of the contents of impurities (C, S, O) < 0.02%. In this example, by weight percentage, the chemical composition of the metal matrix includes: 23% of Co, 20% of Cr, 8.5% of Al, 4% of Ta, 0.6% of Y, and the sum of the contents of impurities (C, S, O) < 0.02%, and the balance is Ni.

[0051] The coating structure fabricated by DED shows precipitated granular or dendritic β-NiAl phases on the γ / γ’ matrix, while the coating fabricated by PBF shows precipitated irregular polygonal β-NiAl phases on the γ / γ’ matrix.

[0052] Example 4

[0053] This application provides a high-temperature oxidation-resistant metal matrix composite coating, which includes a metal matrix and oxide strengthening phases distributed in the metal matrix; by weight percentage, the chemical composition of the metal matrix includes: 22-24% Co, 19-21% Cr, 8-9% Al, 3.5-4.5% Ta, 0.3-0.9% Y, and the sum of the contents of impurities (C, S, O) < 0.02%. In this example, by weight percentage, the chemical composition of the metal matrix includes: 23% Co, 20% Cr, 8.5% Al, 4% Ta, 0.6% Y, and the sum of the contents of impurities (C, S, O) < 0.02%, and the balance is Ni;

[0054] The oxide strengthening phase includes Y 2 O 3 、ZrO 2 or Al 2 O 3 or more than one of them. Specifically, the oxide strengthening phase is Al 2 O 3 , and it is in the shape of ellipsoids or irregular particles;

[0055] As Figure 4 shown in a, b, c, d in

[0056] As Figure 4 shown in e in 2 , the addition of nano-scale oxides makes the precipitated β-NiAl phases during the heat treatment process more refined and dispersed; specifically, the regions with darker contrast in the figure are β-NiAl phases, and the regions with lighter contrast are γ / γ’ matrix. 2 , and the high-temperature oxidation performance is improved by about 2 times.

[0057] Example 5

[0058] As shown in the appendix Figure 1 , this application also proposes a preparation method for a high-temperature oxidation-resistant metal matrix composite coating, which includes the following steps:

[0059] S1, Pretreatment of nanoscale particles, including cleaning, activation, plating, and post-treatment of the nanoscale particles;

[0060] S2, Preparation of spherical powder of nanocomposite reinforced with nanoparticles. Pure substance particles or master alloy particles of Ni, Co, Cr, Al, Ta, Y, pretreated nanoscale particles, and a dispersant are subjected to mechanical alloying in a high-energy ball mill under a protective atmosphere to obtain non-spherical micron-scale powder, and then this non-spherical micron-scale powder is spheroidized by plasma;

[0061] S3, Preparation of coating by additive manufacturing. The prepared spherical powder of nanocomposite reinforced with nanoparticles is screened to obtain powder for preparing the additive manufacturing coating, and the additive coating is prepared by powder bed fusion (abbreviation: PBF) or directed energy deposition (abbreviation: DED) process;

[0062] The technical indexes of the powder prepared by the powder bed fusion PBF process are as follows:

[0063] Particle size D10 = 20 ± 5um, D50 = 25 ± 5um, D90 = 50 ± 5um; Flowability (Hall flow rate) < 25s / 50g; Oxygen content < 500ppm;

[0064] Furthermore, the characteristics of the coating prepared by the PBF method are that the coating can only be prepared on a flat surface. When preparing, a superalloy is used as the substrate. The technical indexes of the prepared coating are: Density > 98%, thickness is 0.3 - 3mm; The microstructure characteristics are: single-phase structure;

[0065] The technical indexes of the powder prepared by the directed energy deposition DED process are as follows:

[0066] Particle size D10 = 50 ± 5um, D50 = 70 ± 5um, D90 = 100 ± 5um; Flowability (Hall flow rate) < 25s / 50g; Oxygen content < 500ppm;

[0067] Furthermore, the characteristics of the coating prepared by the DED method are that the coating can be prepared on a flat surface or a curved surface. The technical indexes of the prepared coating are: Density > 98%, thickness is 1 - 5mm; The microstructure characteristics are: γ single-phase structure;

[0068] S4, Preparation of coating by heat treatment. The prepared coating is heat-treated twice, at 1080°C for 4 hours and 870°C for 20 hours respectively; The microstructure characteristics are: granular or dendritic β-NiAl phase precipitates on the γ / γ' matrix.

[0069] The presence of uniformly distributed nanoscale oxides makes the coating have higher room temperature strength and high temperature strength. The tensile strength of the DED coating without adding nanoscale oxides is about 500MPa, such asFigure 5 As shown, the tensile strength of the high-temperature oxidation-resistant metal matrix composite coating of the present application is 683 MPa at room temperature and 453 MPa at 800 °C.

[0070] A high-temperature oxidation-resistant metal matrix composite coating and a preparation method thereof provided by the present application. The high-temperature oxidation-resistant metal matrix composite coating prepared by additive manufacturing has a denser microstructure, and the coating has higher strength and bonding properties; the method of adding nano-scale oxides by metal alloying enables the nano-scale oxides to act uniformly inside the metal matrix, making the heat treatment more refined and dispersed, reducing the growth rate of the thermally grown oxide layer, having better high-temperature oxidation resistance, and effectively extending the service life of the coating; the additive manufacturing method used in the present application, including powder bed fusion and directed energy deposition, successfully prepares a dense high-temperature oxidation-resistant metal matrix composite coating. After heat treatment, it is beneficial to quickly form a dense and complete alumina layer in the initial stage of oxidation, further protecting the coating from oxidation; the coating is prepared on the high-temperature alloy substrate of the hot-end component through additive manufacturing, which is not limited by the surface shape of the substrate and is easy to realize the manufacturing of the structured coating.

[0071] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, 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 high temperature oxidation resistant metal matrix composite coating, characterized in that: It comprises a metal matrix and an oxide strengthening phase distributed in the metal matrix; The metal matrix is ​​a nickel-based medium entropy alloy, and its chemical composition is Ni, Co, Cr, Al, Ta and Y, wherein the mass content of each element is: Co: 20%-30%, Cr: 19%-30%, Al: 8%-12%, Ta: 3.5%-5%, Y: 0.3%-1.5%, the sum of impurity (C, S, O) content is less than 0.02%, Ni: balance; The oxide strengthening phase includes at least one of Y2O3, ZrO2 or Al2O3.

2. The high temperature oxidation resistant metal matrix composite material coating according to claim 1, characterized in that: The oxide reinforcement phase is nano-scale oxide particles, and the particle size of the nano-scale oxide particles is 2-200 nm.

3. The high temperature oxidation resistant metal matrix composite material coating according to claim 2, characterized in that: The particle size of the nano-scale oxide particles is 5-20 nm.

4. The high temperature oxidation resistant metal matrix composite material coating according to claim 1, characterized in that: The mass percentage of the oxide reinforcement phase in the metal matrix composite coating is 0%-5%.

5. The high temperature oxidation resistant metal matrix composite material coating according to claim 4, characterized in that: The mass percentage of the oxide reinforcement phase in the metal matrix composite coating is 0% or 0.4% or 0.6% or 0.8%.

6. The high temperature oxidation resistant metal matrix composite material coating according to claim 1, characterized in that: The thickness of the metal matrix composite material coating is controlled at 1-5 mm.

7. The high temperature oxidation resistant metal matrix composite material coating according to claim 6, characterized in that: The thickness of the metal matrix composite material coating is controlled at 2-3 mm.

8. A method for preparing a high temperature oxidation resistant metal matrix composite material coating, characterized in that: The steps include: S1, pretreatment of nano-scale particles, cleaning, activation, plating and post-treatment of nano-scale particles; S2, preparation of spherical powder of nanoparticle-reinforced composite material, wherein pure material particles or intermediate alloy particles of Ni, Co, Cr, Al, Ta, Y, pretreated nano-scale particles and dispersant are subjected to mechanical alloying process in a high-energy ball mill under a protective atmosphere to obtain non-spherical micron-scale powder, and then the non-spherical micron-scale powder is subjected to plasma spheroidization and powdering; S3, preparing the coating by additive manufacturing, screening the prepared spherical powder of the nanoparticle-reinforced composite material to obtain powder for preparing the coating by additive manufacturing, and preparing the additive coating by a process of powder bed fusion or directed energy deposition; S4, coating heat treatment preparation, the prepared coating is heat treated twice, respectively at 1080°C for 4 hours and at 870°C for 20 hours.

9. The method for preparing a high temperature oxidation resistant metal matrix composite material coating according to claim 8, characterized in that: The technical indicators of the powder prepared by the powder bed fusion process are: Particle size D10 = 20 ± 5um, D50 = 25 ± 5um, D90 = 50 ± 5um; fluidity (Hall flow rate) < 25s / 50g; oxygen content < 500ppm.

10. The method for preparing a high temperature oxidation resistant metal matrix composite material coating according to claim 8, characterized in that: The technical indicators of the powder prepared by the directed energy deposition process are: Particle size D10 = 50 ± 5um, D50 = 70 ± 5um, D90 = 100 ± 5um; fluidity (Hall flow rate) < 25s / 50g; oxygen content < 500ppm.

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