High temperature oxidation resistant coating, additive manufactured niobium tungsten alloy-nb521 having a high temperature oxidation resistant coating, and methods of making the same

Abstract

The application provides a high-temperature oxidation-resistant coating, an additive manufacturing niobium-tungsten alloy-Nb521 with the high-temperature oxidation-resistant coating and a preparation method of the additive manufacturing niobium-tungsten alloy-Nb521, and relates to the technical field of high-temperature protective coatings. The high-temperature oxidation-resistant coating comprises mixed coating powder and an additive. The mixed coating powder comprises the following components in percentage by mass: MoSi2 is 3.5-5.0 wt%, TiB2 is 1.0-2.0 wt%, ZrO2 is 3.8-6.0 wt%, Nb is 2.0-4.0 wt%, Cr is 3.2-6.8 wt%, W is 4.2-6.0 wt%, Y2O3 is 0.5-1.0 wt%, polyethylene glycol is 1.0-3.0 wt%, and the rest is Si. The additive is anhydrous ethanol. The addition amount of the anhydrous ethanol is 3-5 times the volume of the mixed coating powder. The coating provided by the application has good high-temperature oxidation resistance, the bonding force between the coating and the additive manufacturing niobium-tungsten alloy-Nb521 substrate is strong, the coating structure is dense, and the static use temperature can reach 1850 DEG C.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature protective coating, and particularly relates to a high-temperature oxidation-resistant coating, an additive manufacturing niobium-tungsten alloy-Nb521 with the high-temperature oxidation-resistant coating and a preparation method thereof. BACKGROUND

[0002] The niobium-tungsten alloy is an ideal choice for aerospace high-temperature structural materials due to its high melting point, good high-temperature strength and low density. Traditional niobium-tungsten alloys (such as Nb6621) are mostly formed by pressure processing, which is difficult to manufacture complex structural parts and is high in cost. The additive manufacturing technology, also commonly known as 3D printing, provides a new way for preparing complex structural niobium-tungsten alloy components, but the surface state, grain structure and internal stress formed in the additive manufacturing process are different from those of traditional processes, which leads to the difficulty of direct application of existing high-temperature oxidation-resistant coating systems.

[0003] For example, the Chinese invention patent with the authorization announcement number CN113308689B discloses a niobium-tungsten alloy-Nb6621 high-temperature oxidation-resistant coating material and a preparation method thereof, wherein the niobium-tungsten alloy-Nb6621 high-temperature oxidation-resistant coating material includes, in terms of mass percentage, TaC 5.0-7.0wt%, HfC 4.5-5.5wt%, Al2O3 4.0-4.5wt%, MoSi2 3.5-4.2wt%, Ti 3.0-4.0wt%, ZrO2 2.5-3.0wt%, W 2.0-3.0wt%, Y2O3 1.5-2.0wt%, and Si 66.8-74.0wt%.

[0004] And the above-mentioned niobium-tungsten alloy-Nb6621 high-temperature oxidation-resistant coating material is designed for traditional formed niobium-tungsten alloy-Nb6621. Since the thermal expansion coefficients of different materials are different, the compatibility of niobium-tungsten alloy and coating material is also different, so different alloys must use matching coating. If it is coated on the additive manufacturing niobium-tungsten alloy-Nb521, the phenomenon of poor bonding force, coating cracking or easy peeling will occur, and the purpose of high-temperature oxidation resistance cannot be achieved.

[0005] Therefore, it is urgent to develop a high-temperature oxidation-resistant coating suitable for the additive manufacturing niobium-tungsten alloy-Nb521 to improve its service life in an extremely high-temperature environment. SUMMARY

[0006] Therefore, in view of the above problems, it is necessary to provide a high-temperature oxidation-resistant coating, an additive manufacturing niobium-tungsten alloy-Nb521 with the high-temperature oxidation-resistant coating and a preparation method thereof to improve the service life of the additive manufacturing niobium-tungsten alloy-Nb521 in an extremely high-temperature environment.

[0007] The application solves the technical problems by adopting the technical scheme of

[0008] In a first aspect, the application provides a high-temperature oxidation-resistant coating, comprising mixed coating powder and an additive, wherein the mixed coating powder comprises the following components in percentage by mass:

[0009] MoSi2 is 3.5-5.0wt%, TiB2 is 1.0-2.0wt%, ZrO2 is 3.8-6.0wt%, Nb is 2.0-4.0wt%, Cr is 3.2-6.8wt%, W is 4.2-6.0wt%, Y2O3 is 0.5-1.0wt%, polyethylene glycol is 1.0-3.0wt%, and the rest is Si;

[0010] The additive is anhydrous ethanol, wherein the amount of the anhydrous ethanol added is 3-5 times the volume of the mixed coating powder.

[0011] Preferably, the particle size of MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3 and Si in the mixed coating powder is less than 200 mesh.

[0012] Preferably, the molecular weight of the polyethylene glycol is 3000-8000.

[0013] Preferably, the thickness of the high-temperature oxidation-resistant coating for additive manufacturing niobium tungsten alloy-Nb521 is 60-150μm.

[0014] In a second aspect, the application provides a preparation method of additive manufacturing niobium tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating, comprising the following steps:

[0015] Step 1: mixing MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3, Si and polyethylene glycol according to the proportion to form a mixed coating powder;

[0016] Step 2: adding anhydrous ethanol to the mixed coating powder to form a pretreated slurry;

[0017] Step 3: ball milling and grinding the pretreated slurry for a predetermined time to obtain a coating slurry;

[0018] Step 4: coating the coating slurry on the additive manufacturing niobium tungsten alloy-Nb521 substrate;

[0019] Step 5: vacuum sintering the additive manufacturing niobium tungsten alloy-Nb521 substrate coated with the coating slurry to obtain the additive manufacturing niobium tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating.

[0020] Preferably, in the step 1, the components in the mixed coating powder are as follows in terms of mass percentage:

[0021] MoSi2 is 3.5-5.0wt%, TiB2 is 1.0-2.0wt%, ZrO2 is 3.8-6.0wt%, Nb is 2.0-4.0wt%, Cr is 3.2-6.8wt%, W is 4.2-6.0wt%, Y2O3 is 0.5-1.0wt%, polyethylene glycol is 1.0-3.0wt%, and the balance is Si.

[0022] Preferably, in the step 2, the amount of anhydrous ethanol added is 3-5 times the volume of the mixed coating powder.

[0023] Preferably, in the step 4, the thickness of the coating slurry coated on the additive manufacturing niobium-tungsten alloy-Nb521 substrate is 60-150μm.

[0024] Preferably, in the step 5, the sintering temperature of the sintering treatment is 1300-1600℃, the sintering time is 10-40min, and the vacuum degree is 1.0×10 -2 Pa.

[0025] In a third aspect, the present application provides an additive manufacturing niobium-tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating, which is prepared according to the preparation method of the additive manufacturing niobium-tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating according to the second aspect.

[0026] From the above technical solution, it can be seen that the present application provides a high-temperature oxidation-resistant coating, an additive manufacturing niobium-tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating, and a preparation method thereof, wherein the high-temperature oxidation-resistant coating comprises a mixed coating powder and an additive, and the mixed coating powder comprises the following components in terms of mass percentage: MoSi2 is 3.5-5.0wt%, TiB2 is 1.0-2.0wt%, ZrO2 is 3.8-6.0wt%, Nb is 2.0-4.0wt%, Cr is 3.2-6.8wt%, W is 4.2-6.0wt%, Y2O3 is 0.5-1.0wt%, polyethylene glycol is 1.0-3.0wt%, and the balance is Si; and the additive is anhydrous ethanol, wherein the amount of anhydrous ethanol added is 3-5 times the volume of the mixed coating powder.

[0027] The present application has the following beneficial effects compared with the prior art: the coating provided by the present application not only has good high-temperature oxidation resistance, but also has strong bonding force with the additive manufacturing niobium-tungsten alloy-Nb521 substrate, and the coating structure is dense, and the static use temperature can reach 1850 DEG C. Specifically, the TiB2 added in the mixed coating powder of the present application can form a dense TiO2-B2O3 composite oxide film in a high-temperature environment, which can effectively cover the alloy surface and block the further inward diffusion of oxygen, thereby preventing the additive manufacturing niobium-tungsten alloy-Nb521 from being easily oxidized to form loose and easy-to-peel Nb2O5 and WO3 at high temperature, thereby significantly improving the oxidation resistance of the coating-substrate at high temperature. Meanwhile, the Cr added in the mixed coating powder of the present application has high surface activity, which can improve the wettability between the metal phase (such as Nb and W) and the ceramic phase (TiB2), thereby enhancing the interfacial bonding strength between the coating and the substrate and preventing the coating from cracking or peeling. In addition, the Cr can also reduce the sintering temperature to a certain extent and inhibit the excessive growth of grains during the sintering process, which is beneficial to obtain a coating structure with higher density. ZrO2 and Y2O3 act as sintering aids in the mixed coating powder, which can reduce the sintering temperature of the coating, promote the dense accumulation of powder particles, fill the gaps between other component particles, further inhibit grain growth and reduce internal defects, thereby ensuring the structural integrity of the coating at high temperature. The Nb added in the mixed coating powder of the present application can inhibit the grain coarsening of W through the interfacial diffusion mechanism, and the thermal expansion coefficient of Nb matches the niobium-tungsten alloy substrate, which helps to reduce thermal stress, improve the high-temperature thermal shock resistance of the coating and substrate, and prolong the service life of the additive manufacturing niobium-tungsten alloy-Nb521 substrate under thermal cycling conditions. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed for the description of the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 The surface morphology diagram of the initial high-temperature oxidation-resistant coating of the 6R141 test piece prepared for Example 1.

[0030] Figure 2 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R141 test piece prepared for Example 1 after static test at 1850 DEG C.

[0031] Figure 3 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R145 test piece prepared for Example 2 after room temperature-1800 DEG C. air cooling thermal shock test.

[0032] Figure 4 The surface morphology of the high-temperature oxidation-resistant coating of the 6R146 test piece prepared in Example 2 after room temperature-1800℃ air cooling thermal shock test.

[0033] Figure 5 The surface morphology of the initial high-temperature oxidation-resistant coating of the 6R153 test piece prepared in Example 3.

[0034] Figure 6 The surface morphology of the high-temperature oxidation-resistant coating of the 6R153 test piece prepared in Example 3 after 1850℃ static test.

[0035] Figure 7 The macroscopic photograph of the initial high-temperature oxidation-resistant coating of the 7R141, 7R142 and 7R143 test pieces prepared in Comparative Example.

[0036] Figure 8 The cross-sectional morphology of the high-temperature oxidation-resistant coating of the 7R141 test piece prepared in Comparative Example after room temperature-1800℃ air cooling thermal shock. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0038] In a first aspect, the present application provides a high-temperature oxidation-resistant coating, comprising mixed coating powder and an additive, wherein the mixed coating powder comprises the following components in terms of mass percentage:

[0039] MoSi2 is 3.5-5.0wt%, TiB2 is 1.0-2.0wt%, ZrO2 is 3.8-6.0wt%, Nb is 2.0-4.0wt%, Cr is 3.2-6.8wt%, W is 4.2-6.0wt%, Y2O3 is 0.5-1.0wt%, polyethylene glycol is 1.0-3.0wt%, and the balance is Si;

[0040] The additive is anhydrous ethanol, wherein the addition amount of the anhydrous ethanol is 3-5 times the volume of the mixed coating powder.

[0041] Compared with the prior art, the coating provided by the present application has the advantages of good high-temperature oxidation resistance, strong bonding force between the coating and the additive manufacturing niobium-tungsten alloy-Nb521 substrate, dense coating structure, and a static use temperature of up to 1850 DEG C. Specifically, the TiB2 added in the mixed coating powder can form a dense TiO2-B2O3 composite oxide film in a high-temperature environment, the film layer can effectively cover the alloy surface, block the further inward diffusion of oxygen, and prevent the additive manufacturing niobium-tungsten alloy-Nb521 from being easily oxidized to form loose and easily peeled Nb2O5 and WO3 at high temperatures, thereby significantly improving the oxidation resistance of the coating-substrate at high temperatures. Meanwhile, the Cr added in the mixed coating powder has high surface activity, can improve the wettability between the metal phase (such as Nb and W) and the ceramic phase (TiB2), thereby enhancing the interfacial bonding strength between the coating and the substrate, preventing the coating from cracking or peeling off, and further reducing the sintering temperature, inhibiting the excessive growth of grains in the sintering process, and being conducive to obtaining a coating structure with higher density. The ZrO2 and Y2O3 in the mixed coating powder act as sintering aids, can reduce the sintering temperature of the coating, promote the dense accumulation of powder particles, fill the gaps between other component particles, further inhibit grain growth, reduce internal defects, and thus ensure the structural integrity of the coating at high temperatures. The Nb added in the mixed coating powder can inhibit the grain coarsening of W through the interface diffusion mechanism, and the thermal expansion coefficient of Nb matches the niobium-tungsten alloy substrate, which helps to reduce thermal stress, improve the high-temperature thermal shock resistance of the coating and the substrate, and prolong the service life of the additive manufacturing niobium-tungsten alloy-Nb521 substrate under thermal cycling conditions.

[0042] Further, the particle size of MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3 and Si in the mixed coating powder is less than 200 mesh.

[0043] Further, the molecular weight of the polyethylene glycol is 3000-8000. In this molecular weight range, the polyethylene glycol can provide appropriate viscosity and viscosity. If the molecular weight is too low (such as <3000), the polyethylene glycol is too "thin" and cannot effectively bind and suspend the powder particles, which can easily lead to slurry settling, layering, and easy flow during coating, making it difficult to control the thickness. If the molecular weight is too high (such as >8000), the slurry will be too viscous, the flowability will be poor, and the slurry will be unevenly dispersed during spraying or dipping, which can easily form local over-thickness or accumulation, affecting the uniformity and surface flatness of the coating.

[0044] Further, the thickness of the high-temperature oxidation-resistant coating for the additive manufacturing niobium-tungsten alloy-Nb521 is 60-150 μm.

[0045] In a second aspect, the present application provides a preparation method of additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating, comprising the following steps:

[0046] Step 1: MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3, Si and polyethylene glycol are mixed according to the proportion to form a mixed coating powder;

[0047] Step 2: Add anhydrous ethanol to the mixed coating powder to form a pretreated slurry;

[0048] Step 3: Ball mill the pretreated slurry for a predetermined time to obtain a coating slurry, wherein the predetermined time is 3-5h;

[0049] Step 4: The coating slurry is coated on the additive manufacturing niobium-tungsten alloy-Nb521 substrate, and the coating method can be spraying or dipping;

[0050] Step 5: After vacuum sintering treatment of the additive manufacturing niobium-tungsten alloy-Nb521 substrate coated with the coating slurry, the additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating is prepared.

[0051] Further, in step 1, the components in the mixed coating powder are as follows in terms of mass percentage:

[0052] MoSi2 is 3.5-5.0wt%, TiB2 is 1.0-2.0wt%, ZrO2 is 3.8-6.0wt%, Nb is 2.0-4.0wt%, Cr is 3.2-6.8wt%, W is 4.2-6.0wt%, Y2O3 is 0.5-1.0wt%, polyethylene glycol is 1.0-3.0wt%, and the balance is Si.

[0053] Further, in step 2, the amount of anhydrous ethanol added is 3-5 times the volume of the mixed coating powder.

[0054] Further, in step 4, the thickness of the coating slurry coated on the additive manufacturing niobium-tungsten alloy-Nb521 substrate is 60-150μm.

[0055] Further, in step 5, the sintering temperature of the sintering treatment is 1300-1600℃, the sintering time is 10-40min, and the vacuum degree is 1.0×10 -2 Pa.

[0056] In a third aspect, the present application provides an additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating, which is prepared according to the preparation method of additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating of the second aspect.

[0057] The preparation process of the additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating is shown by the following examples of the present method and the comparative examples of the conventional method.

[0058] Example 1: The component raw materials are weighed according to the mass percentage: MoSi2 is 3.5wt%, TiB2 is 1.0wt%, ZrO2 is 3.8wt%, Nb is 2.0wt%, Cr is 3.2wt%, W is 4.2wt%, Y2O3 is 0.5wt%, and polyethylene glycol is 2.0wt%, and the balance is Si, wherein the particle size of MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3, and Si is less than 200 mesh, and the molecular weight of polyethylene glycol is 3000-8000. The above component raw materials are mixed to obtain a mixed coating powder. Anhydrous ethanol is added to the mixed coating powder, and the amount of anhydrous ethanol added is 4 times the volume of the mixed coating powder. After the pretreated slurry is ground for 4h using a ball mill, a coating slurry is obtained. The coating slurry is dip-coated on the additive manufacturing niobium-tungsten alloy-Nb521 substrate, and the additive manufacturing niobium-tungsten alloy-Nb521 substrate coated with the coating slurry is subjected to vacuum sintering treatment, wherein the sintering temperature of the sintering treatment is 1450℃, the sintering time is 15min, the vacuum degree is 1.0×10 -2 Pa, to obtain the additive manufacturing niobium-tungsten alloy-Nb521 with high-temperature oxidation-resistant coating. Four test pieces are thus made and are sequentially labeled as 6R141, 6R142, 6R143, and 6R144.

[0059] Example 2: Compared with Example 1, in the mixed coating powder of the present example, MoSi2 is 5.0wt%, TiB2 is 2.0wt%, ZrO2 is 6.0wt%, Nb is 4.0wt%, Cr is 6.8wt%, W is 6.0wt%, Y2O3 is 1.0wt%, and polyethylene glycol is 2.0wt%, and the balance is Si. The other conditions are the same as those of Example 1. Four test pieces are made and are sequentially labeled as 6R145, 6R146, 6R147, and 6R148.

[0060] Example 3: Compared with Example 1, in the mixed coating powder of the present example, MoSi2 is 3.8wt%, TiB2 is 1.1wt%, ZrO2 is 5.7wt%, Nb is 3.0wt%, Cr is 4.0wt%, W is 4.6wt%, Y2O3 is 1.0wt%, and polyethylene glycol is 2.0wt%, and the balance is Si. The other conditions are the same as those of Example 1. Four test pieces are made and are sequentially labeled as 6R153, 6R154, 6R155, and 6R156.

[0061] The coating raw material powder is mixed according to the ratio of 5.0wt% TaC, 4.5wt% HfC, 4.0wt% Al2O3, 3.5wt% MoSi2, 3.0wt% Ti, 2.5wt% ZrO2, 2.0wt% W, 1.5wt% Y2O3, and the balance of Si. 2.0wt% polyethylene glycol is added, and then 1.0 times the total volume of the above-mentioned powder of anhydrous ethanol is added, and then the mixture is ground for 8 hours by a ball mill to obtain a coating slurry. The coating slurry is dip-coated on the additive manufacturing niobium-tungsten alloy-Nb521 substrate, and the coated alloy coating piece is sintered at 1500°C, 1.0×10 -2 Pa for 30 minutes in a vacuum to obtain an additive manufacturing niobium-tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating. Four test pieces are thus produced and are sequentially labeled as 7R141, 7R142, 7R143, and 7R144.

[0062] The test pieces produced in Example 1, Example 2, Example 3, and the comparative example are subjected to static detection: the test pieces are directly powered, and in an air environment, the test pieces are heated to the required static oxidation-resistant temperature (such as 1850°C) by power supply, and are kept at temperature until the test pieces fail, and the time from heating to failure of the coating is the static oxidation-resistant life of the coating. The appearance of black spots is the timing cutoff point; and in the experiment, defects such as coating peeling, surface blackening, powder falling, cracking, and bubbling should not occur.

[0063] The test pieces produced in Example 1, Example 2, Example 3, and the comparative example are subjected to thermal shock test: the test pieces are directly powered, and in an air environment, the test pieces are heated to the required temperature (such as 1800°C) by power supply for 10-18s and are kept at temperature for 400-500s, and then the test pieces are air-cooled to room temperature for 20-30s, which is one thermal shock. The above process is repeated until the test pieces fail, and the number of thermal shocks experienced is the thermal shock life of the coating. In the experiment, defects such as coating peeling and surface blackening should not occur.

[0064] Table 1. Performance data of the test pieces produced in Example 1

[0065]

[0066] Table 2. Performance data of the test pieces produced in Example 2

[0067]

[0068] Table 3. Performance data of the test pieces produced in Example 3

[0069]

[0070] Table 4. Performance data of the test pieces produced in the comparative example

[0071]

[0072] Please refer to Table 1 to Table 4, in the "room temperature-1800℃ air cooling thermal shock" test, the thermal shock life of all example test pieces is ≥3 times, the highest can reach 8 times (such as test piece 6R142, 6R146), while the comparative example test pieces (7R141, 7R142) fail after the first thermal shock, the life is only 1 time; in the "1850℃ static" oxidation resistance test, the failure time of the example test pieces is more than 2 hours, the longest is 2 hours and 51 minutes (6R144), while the comparative example test pieces (7R143, 7R144) fail after only 10-12 minutes, compared with the comparative example, the high-temperature oxidation-resistant coating provided by the application makes the thermal shock life of the additive manufacturing niobium-tungsten alloy-Nb521 increase several times, the static oxidation resistance life increases more than one order of magnitude, and the comprehensive performance is greatly improved, which directly verifies the technical advantages described in the background and beneficial effects part of the application, that is, through the synergistic effect of MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3, Si and polyethylene glycol components, the problem of high-temperature oxidation and protection of additive manufacturing niobium-tungsten alloy-Nb521 is effectively solved.

[0073] Figure 1 The surface morphology diagram of the initial high-temperature oxidation-resistant coating of the 6R141 test piece prepared in Example 1 is shown in Figure 2 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R141 test piece prepared in Example 1 after 1850℃ static test is shown in

[0074] Figure 3 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R145 test piece prepared in Example 2 after room temperature-1800℃ air cooling thermal shock test is shown in Figure 4 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R146 test piece prepared in Example 2 after room temperature-1800℃ air cooling thermal shock test is shown in

[0075] Figure 5 The surface morphology diagram of the initial high-temperature oxidation-resistant coating of the 6R153 test piece prepared in Example 3 is shown in Figure 6 The surface morphology diagram of the high-temperature oxidation-resistant coating of the 6R153 test piece prepared in Example 3 after 1850℃ static test is shown in

[0076] Figure 7 The macroscopic photograph of the initial high-temperature oxidation-resistant coating of the 7R141, 7R142, 7R143 test piece prepared in the comparative example is shown in Figure 8 The cross-sectional morphology diagram of the high-temperature oxidation-resistant coating of the 7R141 test piece prepared in the comparative example after room temperature-1800℃ air cooling thermal shock is shown in

[0077] Please refer to Figures 1 to 8 The high-temperature oxidation-resistant coating prepared in the example of the application has the advantages of Figure 1 ,Figure 5 ) initial state presents high density and uniformity. After severe high-temperature static oxidation ( Figure 2 , Figure 6 ) or thermal shock cycle ( Figure 3 , Figure 4 ) test, the high-temperature oxidation-resistant coating structure can still maintain integrity, effectively protecting the additive manufacturing niobium-tungsten alloy-Nb521 substrate. From the initial morphology ( Figure 7 ) of the high-temperature oxidation-resistant coating of the comparative example, it can be observed that the structure is relatively loose, the porosity is relatively high, the bonding strength between the substrate is insufficient, and the initial quality is obviously poor. After thermal shock test ( Figure 8 ), the high-temperature oxidation-resistant coating has serious structural damage, obvious penetrating cracks appear, and even local peeling occurs, completely losing the protection function. These micro-morphology comparisons, together with the macro-performance data in Tables 1 to 4, jointly confirm the significant advantages of the high-temperature oxidation-resistant coating provided by the present application in terms of density, interfacial bonding strength and thermal stress damage resistance.

[0078] The above only discloses the preferred embodiments of the present application, of course, cannot limit the scope of the right of the present application, those skilled in the art can understand that the implementation of all or part of the above-mentioned embodiments, and the equivalent changes made according to the claims of the present application, still belong to the scope covered by the present application.

Claims

1. A method for producing an additive manufactured niobium tungsten alloy - Nb521 with high temperature oxidation resistant coating, characterized in that, The method comprises the following steps: Step 1: mixing MoSi2, TiB2, ZrO2, Nb, Cr, W, Y2O3, Si and polyethylene glycol according to a proportion to form a mixed coating powder; In the step 1, the components in the mixed coating powder are as follows in terms of mass percentage: MoSi2 is 3.5-5.0 wt%, TiB2 is 1.0-2.0 wt%, ZrO2 is 3.8-6.0 wt%, Nb is 2.0-4.0 wt%, Cr is 3.2-6.8 wt%, W is 4.2-6.0 wt%, Y2O3 is 0.5-1.0 wt%, polyethylene glycol is 1.0-3.0 wt%, and the rest is Si; Step 2: adding anhydrous ethanol to the mixed coating powder to form a pretreated slurry; Step 3: ball-milling and grinding the pretreated slurry for a predetermined time to obtain a coating slurry; Step 4: coating the coating slurry on an additive manufacturing niobium tungsten alloy-Nb521 substrate; Step 5: performing vacuum sintering treatment on the additive manufacturing niobium tungsten alloy-Nb521 substrate coated with the coating slurry to obtain an additive manufacturing niobium tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating.

2. The method for preparing additively manufactured niobium-tungsten alloy-Nb521 with a high-temperature anti-oxidation coating as described in claim 1, characterized in that, In the step 2, the amount of the anhydrous ethanol added is 3-5 times the volume of the mixed coating powder.

3. The method for preparing additively manufactured niobium-tungsten alloy-Nb521 with a high-temperature antioxidant coating as described in claim 1, characterized in that, In the step 4, the thickness of the coating slurry coated on the additive manufacturing niobium tungsten alloy-Nb521 substrate is 60-150 μm.

4. The method for preparing additively manufactured niobium-tungsten alloy-Nb521 with a high-temperature antioxidant coating as described in claim 1, characterized in that, The sintering temperature of the sintering treatment in the step 5 is 1300-1600℃, the sintering time is 10-40min, and the vacuum degree is 1.0x10 -2 Pa.

5. Additively manufactured niobium tungsten alloy - Nb521 with high temperature oxidation resistant coating, characterized in that, The additive manufacturing niobium tungsten alloy-Nb521 with a high-temperature oxidation-resistant coating is prepared according to the method of any one of claims 1-4.

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