CN113025951A - Molybdenum alloy containing antioxidant composite coating and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种含抗氧化复合涂层的钼合金及其制备方法，涉及高温合金热防护技术领域，包含钼合金基体及其表面的复合涂层，所述复合涂层至少包含(Mo,X)Si₂相和(Cr,X)Si₂相，所述复合涂层还可以具有双层结构，其外层至少包含(Mo,X)Si₂相和(Cr,X)Si₂相，内层至少包含(Mo,X)₅Si₃相；其中，(Mo,X)Si₂中X代表Cr、Ti或W，(Cr,X)Si₂中X代表Mo、Ti或W，制备方法包括钼合金基体的制备以及在合金表面采用共渗制备复合涂层，本发明采用基体合金化和表面改性相结合，合金化、复合法和多层结构联合改性硅化物涂层的方法制备了(Mo,X)Si₂‑(Cr,X)Si₂基复合涂层保护的钼合金，其具有优异的中温和高温抗氧化能力。The invention discloses a molybdenum alloy containing an anti-oxidation composite coating and a preparation method thereof, and relates to the technical field of thermal protection of high-temperature alloys. X)Si₂ phase and (Cr,X)Si₂ phase, the composite coating may also have a double-layer structure, the outer layer of which at least contains (Mo,X)Si₂ phase and (Cr,X)Si₂ phase, The inner layer contains at least (Mo,X)₅ Si₃ phase; wherein, X in (Mo, X) Si₂ represents Cr, Ti or W, and X in (Cr, X) Si₂ represents Mo, Ti or W, preparation method Including the preparation of molybdenum alloy matrix and the preparation of composite coating by co-infiltration on the surface of the alloy, the invention adopts the method of combining matrix alloying and surface modification, alloying, composite method and multi-layer structure to jointly modify silicide coating. A molybdenum alloy protected by a (Mo,X)Si₂ -(Cr,X)Si₂ -based composite coating has excellent medium and high temperature oxidation resistance.

Description

Molybdenum alloy containing antioxidant composite coating and preparation method thereof

Technical Field

The invention relates to the technical field of high-temperature alloy thermal protection, in particular to a molybdenum alloy containing an antioxidant composite coating and a preparation method thereof.

Background

The molybdenum and the alloy thereof have the advantages of high melting point, low resistivity, high thermal conductivity, low thermal expansion coefficient, high-temperature strength and the like, are key materials for preparing rocket nozzles, nozzle throat liners, radiation shields, heat shields, heating elements and the like, and have wide application prospects in the fields of aerospace, nuclear industry, machinery, metallurgy and the like. However, molybdenum and molybdenum alloys are rapidly oxidized to volatile MoO in an air environment above 600 deg.C₃Severely restricting the use of the material as a high-temperature material.

At present, the high-temperature oxidation resistance of molybdenum mainly comprises alloying and surface modification. The alloying method is to add antioxidant alloy elements (such as zirconium, chromium and aluminum) into molybdenum, and in the high-temperature oxidation process, the antioxidant alloy elements are selectively oxidized, so that the oxidation rate of the molybdenum is slowed down to a certain extent. However, the alloying method has certain limitation in improving the high-temperature oxidation resistance, and a dense and continuous protective oxide film cannot be formed on the surface of the molybdenum alloy by only adding alloying elements. The surface modification can give consideration to the oxidation resistance and the mechanical property of the alloy, and the oxidation resistance of the matrix metal is obviously improved. Silicide coatings (e.g. MoSi)₂Etc.) has the advantages of high melting point, good thermal stability, excellent oxidation resistance, self-healing capability and the like, and is a high-temperature oxidation-resistant coating system which is most widely applied to the surface of refractory metals. According to the current research situation at home and abroad, the silicide coating prepared on the surface of the molybdenum alloy has the main problems that: (1) single MoSi₂Although the coating has excellent high-temperature oxidation resistance, the coating has poor high-temperature oxidation resistance, and the coating can generate 'moulding' pulverization oxidation at 400-600 ℃; (2) MoSi₂The difference of the thermal expansion coefficients between the coating and the matrix is large, cracks are easily generated in the coating and at the joint of the coating and the matrix interface, so that the coating fails and the thermal shock resistance is poor; (3) MoSi₂After oxidation of the coatingSurface formed SiO₂The membrane has good fluidity at high temperature and thus insufficient resistance to gas scouring. The development trend of molybdenum and molybdenum alloy high-temperature oxidation resistant coatings is that the molybdenum and molybdenum alloy high-temperature oxidation resistant coatings have excellent oxidation resistance, thermal shock resistance and gas scouring resistance at a wider use temperature. However, there is no established method to solve the above problems at the same time.

Disclosure of Invention

The invention aims to solve at least one technical problem in the prior art and provides a molybdenum alloy containing an antioxidant composite coating and a preparation method thereof.

The technical solution of the invention is as follows:

a molybdenum alloy containing an oxidation-resistant composite coating, comprising a molybdenum alloy substrate and a composite coating on the surface of the molybdenum alloy substrate, wherein the composite coating at least comprises (Mo, X) Si₂Phase of (Cr, X) Si₂Phase(s) of each other.

Preferably, the composite coating is a double-layer structure, and the outer layer at least comprises (Mo, X) Si₂Phase of (Cr, X) Si₂The inner layer at least comprises (Mo, X)₅Si₃And (4) phase(s).

Preferably, the outer layer and/or the inner layer further comprises Al₂O₃Phase, (Mo, X) Si₂Wherein X represents Cr, Ti or W, (Cr, X) Si₂Wherein X represents Mo, Ti or W.

Preferably, the molybdenum alloy matrix comprises the following composition: 10 to 30 at% Cr, 0 to 15 at% Al, 0 to 30 at% W, 0 to 15 at% Ti, and the balance Mo.

The invention also discloses a preparation method of the molybdenum alloy containing the antioxidant composite coating, which comprises the steps of alloying the substrate to obtain a molybdenum alloy substrate, and then preparing the composite coating on the molybdenum alloy substrate to reduce the difference of the thermal expansion coefficients of the molybdenum alloy substrate and the composite coating. The method specifically comprises the following steps:

the method comprises the following steps: mixing Mo powder, Cr powder, Al powder, W powder and Ti powder in proportion, putting the mixture into a ball mill for ball milling, drying, sequentially performing compression molding on the dried powder, and sintering at low pressure to obtain a molybdenum alloy matrix;

step two: will be described in step oneAfter the molybdenum alloy matrix is ground, polished and cleaned, the molybdenum alloy matrix is placed in a tube furnace, NH is introduced into the tube furnace₃Keeping the temperature at 800-1200 ℃ for 2-5 h at a flow rate of 100-300 ml/min, and then cooling along with the furnace;

step three: mixing silicon powder, sodium fluoride powder, sodium fluosilicate powder and alumina powder according to a certain proportion, and performing ball milling to obtain penetrant powder;

step four: filling the infiltration agent powder obtained in the step three into an alumina crucible, embedding the molybdenum alloy matrix obtained in the step one into the infiltration agent powder obtained in the step three, covering the crucible and using Al₂O₃Sealing the slurry prepared by the powder and the silica sol; and (3) placing the sealed crucible into a high-temperature tube furnace, heating to 1000-1300 ℃ under the protection of argon, preserving the temperature for 15-30 h, and cooling along with the furnace to obtain the molybdenum alloy containing the composite coating.

Preferably, in the first step, the specific conditions of ball milling are as follows: the ball-material ratio is 5-10: 1, the rotating speed is 100-200 r/min, and the ball milling time is 10-40 h.

Preferably, in the step one, the temperature of low-pressure sintering is 1600-1800 ℃, and the temperature is kept for 2-5 hours.

Preferably, in the third step, the penetrant powder is prepared by uniformly mixing the following raw materials in percentage by mass: 20-30% of silicon powder, 2-6% of sodium fluoride powder, 1-3% of sodium fluosilicate powder, 56-70% of alumina powder and 0-5% of yttrium oxide powder.

Preferably, the purity of the silicon powder, the sodium fluoride powder, the sodium fluosilicate powder, the yttrium oxide powder and the aluminum oxide is not lower than 99.0%.

Preferably, in the third step, the ball milling is specifically performed for 1-3 hours by a planetary ball mill at a speed of 100-250 r/min.

The invention has at least one of the following beneficial effects:

(1) the invention adopts the combination of matrix alloying and surface modification, and the alloying and compounding method and the method of multilayer structure combined modification silicide coating to prepare (Mo, X) Si₂-(Cr,X)Si₂Molybdenum alloy protected by base composite coating and having excellent medium temperature and high temperatureAntioxidant ability.

(2) The invention adopts alloying of the matrix and simultaneously prepares the composite coating on the surface thereof, thus reducing the difference of the thermal expansion coefficients of the matrix and the composite coating, forming a compact coating with good interface bonding and improving the thermal shock resistance of the material; (Mo, X) Si prepared on surface of molybdenum alloy by pack cementation₂-(Cr,X)Si₂The base composite coating is compact and uniform, and the combination of the matrix and the coating is good. SiO formed on the surface of the alloy during oxidation₂·Al₂O₃The protective film has larger viscosity and is beneficial to the anti-scouring capability of the material.

(3) The method has the advantages of simple process, convenient operation, low cost, high yield, high efficiency and the like, is suitable for industrial popularization and application, and has important practical value for preparing high-temperature hot end parts in the fields of aerospace, nuclear industry, machinery, metallurgy and the like.

Drawings

FIG. 1 is a graph of the oxidation weight gain at 1300 ℃ after Si-Y co-doping of different substrates of molybdenum-based alloys alone (examples 1-4);

FIG. 2 is a cross-sectional microstructure of a Mo-30Cr-10Al-5W alloy coating in which (a) Si is infiltrated alone (example 3 sample), (b) Si-Y is infiltrated (example 4 sample);

FIG. 3 is a surface texture of Mo-30Cr-10Al-5W alloy after Si-Y co-cementation oxidized for 280 hours at 1300 ℃ (sample of example 4);

FIG. 4 is a graph of the oxidation rate of weight gain for Mo-30Cr-10Al-5W alloy after Si-Y co-cementation, oxidized at 500 deg.C and 900 deg.C for 80 hours (sample of example 4).

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

to verify the effect of the invention, (Mo, X) Si was prepared on the surface of the alloy by two-step method using different base alloys₂-(Cr,X)Si₂And carrying out a cyclic oxidation test for 80-280 h on the composite coating under the atmospheric environment at the temperature of 500-1300 ℃.

Example 1:

the method comprises the following steps: preparation of Mo-based alloy

Mixing materials according to the proportion of 85 at% of Mo and 15 at% of Cr, wet grinding by adopting a planetary ball mill, wherein the ball-material ratio is 5:1, the rotating speed is 120r/min, the ball milling time is 30 hours, and after the ball milling is finished, putting the powder into a vacuum drying oven for drying. And then putting the dried powder into a cold isostatic pressing die for pressing and molding. And (3) sintering the pressed sample at 1600 ℃ and 0.6Mpa under low pressure, and keeping the temperature for 3 hours to prepare the Mo-15Cr matrix alloy.

Step two: preparing (Mo, X) Si on the surface of the alloy obtained in the step one₂-(Cr,X)Si₂Base composite coating

And gradually grinding and polishing the alloy surface by using 240#, 400#, 600# and 1000# silicon carbide abrasive paper, ultrasonically cleaning in absolute ethyl alcohol, and drying. Placing the treated sample in an alumina crucible, placing the alumina crucible in a tube furnace, and introducing NH into the tube furnace₃And the flow is 200ml/min, the surface nitriding treatment is carried out at the temperature of 1000 ℃ for 3 hours, and a nitride transition layer is obtained on the surface of the alloy after the heat preservation is finished. Mixing silicon powder, sodium fluoride powder, sodium fluosilicate powder and alumina powder according to a certain proportion, and then carrying out ball milling for 2 hours at 150 revolutions per minute by a planetary ball mill to obtain penetrant powder; wherein the purity of the silicon powder, the sodium fluoride powder, the sodium fluosilicate powder and the aluminum oxide is not lower than 99.0 percent; wherein, 25 wt% of silicon powder, 4 wt% of sodium fluoride powder, 2 wt% of sodium fluosilicate powder and 69 wt% of alumina powder. Filling the penetrant powder into an alumina crucible, burying the Mo-15Cr matrix alloy subjected to surface nitriding treatment in the penetrant powder, covering the crucible cover and using Al₂O₃Sealing the slurry prepared by the powder and the silica sol; placing the sealed crucible in a high-temperature tube furnace, heating to 1200 ℃ under the protection of argon, and preserving heat for 20 hours to finish Si infiltration treatment to obtain (Mo, Cr) Si₂-(Cr,Mo)Si₂A composite coating; and (3) performing a 150-hour cyclic oxidation experiment on the sample subjected to the Si infiltration treatment at 1300 ℃ in an atmospheric environment, wherein the surface oxide film is compact and complete, the peeling phenomenon is avoided, and the oxidation weight gain rate is 0.43% (refer to figure 1).

Example 2:

the method comprises the following steps: preparation of Mo-based alloy

Proportioning according to the proportion of 75 at% of Mo and 25 at% of Cr, wet grinding by adopting a planetary ball mill, wherein the ball-material ratio is 5:1, the rotating speed is 120r/min, the ball milling time is 30h, and after the ball milling is finished, putting the powder into a vacuum drying oven for drying. And then putting the dried powder into a cold isostatic pressing die for pressing and molding. And (3) sintering the pressed sample at 1600 ℃ and 0.6Mpa under low pressure, and keeping the temperature for 3 hours to prepare the Mo-25Cr matrix alloy.

Step two: preparing (Mo, X) Si on the surface of the alloy obtained in the step one₂-(Cr,X)Si₂Base composite coating

And gradually grinding and polishing the alloy surface by using 240#, 400#, 600# and 1000# silicon carbide abrasive paper, ultrasonically cleaning in absolute ethyl alcohol, and drying. Placing the treated sample in an alumina crucible, placing the alumina crucible in a tube furnace, and introducing NH into the tube furnace₃And the flow is 200ml/min, the surface nitriding treatment is carried out at the temperature of 1000 ℃ for 3 hours, and a nitride transition layer is obtained on the surface of the alloy after the heat preservation is finished. Mixing silicon powder, sodium fluoride powder, sodium fluosilicate powder and alumina powder according to a certain proportion, and then carrying out ball milling for 2 hours at 150 revolutions per minute by a planetary ball mill to obtain penetrant powder; wherein the purity of the silicon powder, the sodium fluoride powder, the sodium fluosilicate powder and the aluminum oxide is not lower than 99.0 percent; wherein, the silicon powder accounts for 25 wt%, the sodium fluoride powder accounts for 4 wt%, the sodium fluosilicate powder accounts for 2 wt%, and the alumina powder accounts for 69 wt%. Filling the penetrant powder into an alumina crucible, burying the Mo-25Cr matrix alloy subjected to surface nitriding treatment in the penetrant powder, covering the crucible cover and using Al₂O₃Sealing the slurry prepared by the powder and the silica sol; placing the sealed crucible in a high-temperature tube furnace, heating to 1200 ℃ under the protection of argon, and preserving heat for 20 hours to finish Si infiltration treatment to obtain (Mo, Cr) Si₂-(Cr,Mo)Si₂A composite coating; and (3) performing a 150-hour cyclic oxidation experiment on the sample subjected to the Si infiltration treatment at 1300 ℃ in an atmospheric environment, wherein the surface oxide film is compact and complete, the peeling phenomenon is avoided, and the oxidation weight gain rate is 0.36% (refer to figure 1).

Example 3:

the method comprises the following steps: preparation of Mo-based alloy

Preparing materials according to the proportion of 30 at% Cr, 10 at% Al, 5 at% W and the balance Mo, wet-grinding by adopting a planetary ball mill, wherein the ball-material ratio is 5:1, the rotating speed is 120r/min, the ball-milling time is 30h, and after the ball-milling is finished, putting the powder into a vacuum drying oven for drying. And then putting the dried powder into a cold isostatic pressing die for pressing and molding. And (3) sintering the pressed sample at 1600 ℃ and 0.6Mpa under low pressure, and keeping the temperature for 3 hours to prepare the Mo-30Cr-10Al-5W matrix alloy.

Step two: preparing (Mo, X) Si on the surface of the alloy obtained in the step one₂-(Cr,X)Si₂Base composite coating

And gradually grinding and polishing the surface of the molybdenum matrix alloy by using 240#, 400#, 600# and 1000# silicon carbide abrasive papers, ultrasonically cleaning in absolute ethyl alcohol, and drying. Placing the treated sample in an alumina crucible, placing the alumina crucible in a tube furnace, and introducing NH into the tube furnace₃And the flow is 200ml/min, the surface nitriding treatment is carried out at the temperature of 1000 ℃ for 3 hours, and a nitride transition layer is obtained on the surface of the alloy after the heat preservation is finished. Mixing silicon powder, sodium fluoride powder, sodium fluosilicate powder and alumina powder according to a certain proportion, and then carrying out ball milling for 2 hours at 150 revolutions per minute by a planetary ball mill to obtain penetrant powder; wherein the purity of the silicon powder, the sodium fluoride powder, the sodium fluosilicate powder and the aluminum oxide is not lower than 99.0 percent; wherein, 25 wt% of silicon powder, 4 wt% of sodium fluoride powder, 2 wt% of sodium fluosilicate powder and 69 wt% of alumina powder. Filling Si penetrant powder into an alumina crucible, burying the Mo-30Cr-10Al-5W matrix alloy subjected to surface nitriding treatment in the penetrant powder, covering the crucible and using Al₂O₃Sealing the slurry prepared by the powder and the silica sol; placing the sealed crucible in a high-temperature tube furnace, heating to 1200 ℃ under the protection of argon, and preserving heat for 20 hours to finish Si infiltration treatment to obtain (Mo, X) Si₂-(Cr,X)Si₂The thickness of the base composite coating was 307 μm (see FIG. 2 a). The sample after the Si infiltration treatment is subjected to a 150-hour cyclic oxidation experiment in an atmospheric environment at 1300 ℃, the surface oxide film is compact and complete, the peeling phenomenon is avoided, and the oxidation weight gain rate is-0.03% (refer to figure 1).

Example 4:

the method comprises the following steps: preparation of Mo-based alloy

Preparing materials according to the proportion of 30 at% Cr, 10 at% Al, 5 at% W and the balance Mo, wet-grinding by adopting a planetary ball mill, wherein the ball-material ratio is 5:1, the rotating speed is 120r/min, the ball-milling time is 30h, and after the ball-milling is finished, putting the powder into a vacuum drying oven for drying. And then putting the dried powder into a cold isostatic pressing die for pressing and molding. And sintering the pressed sample at 1600 ℃ under low pressure, and keeping the temperature for 3 hours to prepare the Mo-30Cr-10Al-5W matrix alloy.

Step two: preparing (Mo, X) Si on the alloy surface obtained in the step one by Si-Y co-infiltration₂-(Cr,X)Si₂Base composite coating

And gradually grinding and polishing the surface of the molybdenum matrix alloy by using 240#, 400#, 600# and 1000# silicon carbide abrasive papers, ultrasonically cleaning in absolute ethyl alcohol, and drying. Placing the treated sample in an alumina crucible, placing the alumina crucible in a tube furnace, and introducing NH into the tube furnace₃And the flow is 200ml/min, the surface nitriding treatment is carried out at the temperature of 1000 ℃ for 3 hours, and a nitride transition layer is obtained on the surface of the alloy after the heat preservation is finished. Mixing silicon powder, sodium fluoride powder, sodium fluosilicate powder, yttrium oxide powder and alumina powder according to a certain proportion, and then carrying out ball milling for 2 hours at 150 revolutions per minute by a planetary ball mill to obtain Si-Y co-infiltration agent powder; wherein the purity of the silicon powder, the sodium fluoride powder, the sodium fluosilicate powder, the yttrium oxide powder and the aluminum oxide is not lower than 99.0 percent; wherein, the silicon powder accounts for 25 wt%, the sodium fluoride powder accounts for 4 wt%, the sodium fluosilicate powder accounts for 2 wt%, the yttrium oxide powder accounts for 3 wt%, and the aluminum oxide powder accounts for 66 wt%. Filling Si-Y co-infiltration agent powder into an alumina crucible, burying the Mo-30Cr-10Al-5W matrix alloy subjected to surface nitriding treatment in the infiltration agent powder, covering the crucible and using Al₂O₃Sealing the slurry prepared by the powder and the silica sol; and (3) placing the sealed crucible into a high-temperature tube furnace, heating to 1200 ℃ under the protection of argon, and preserving heat for 20 hours to obtain the Y modified composite coating.

The thickness of the Y modified composite coating is 488 mu m, the Y modified composite coating is of a double-layer structure, and the outer layer is mainly (Mo, X) Si₂+(Cr,X)Si₂+Al₂O₃The inner layer is mainly (Mo, X)₅Si₃+Al₂O₃Phase (see fig. 2 b). The sample after Si-Y co-permeation is subjected to a 280-hour cyclic oxidation experiment at 1300 ℃ in an atmospheric environment, the surface oxide film is compact and complete, the peeling phenomenon is avoided, and the oxidation weight gain rate is only 0.35 percent (reference attached with the weight)Fig. 1). FIG. 3 shows the microscopic appearance of the oxide film on the surface of the alloy after the alloy is oxidized for 280h at 1300 ℃ in the atmospheric environment, wherein the oxide film is mainly composed of dense SiO₂·Al₂O₃Film and Cr distributed thereon₂O₃And Y₂O₃And (4) forming. The sample after Si-Y co-permeation is subjected to 80h cyclic oxidation experiments at 900 ℃ and 500 ℃ in the atmospheric environment, the oxidation weight gain rates are only 0.14% and 0.02% respectively (refer to figure 4), and no 'Pesting' pulverization oxidation occurs. (Mo, X) Si₂-(Cr,X)Si₂The molybdenum-based alloy protected by the base composite coating has excellent oxidation resistance and good stability within the temperature range of 500-1300 ℃.

Simultaneously using a single MoSi₂The bulk material as a control was found to be completely powdered by oxidation at 500 ℃ for 48h, whereas examples 1 to 4 show, on the one hand, a combination of alloying of the matrix and modification of the coating, in which the coating structure is (Mo, X) Si₂-(Cr,X)Si₂/(Mo,X)₅Si₃The composite coating reduces the difference of the thermal expansion coefficients of the two, and can form a compact coating with good interface combination; on the other hand, referring to the attached figure 1, the alloy in the embodiment undergoes cyclic oxidation times of 31 times (total oxidation time is 280 hours) at 1300 ℃, the surface is compact and complete, no stripping occurs, and the excellent thermal shock resistance can be shown.

In the description of the embodiments of the present invention, it should be understood that "-" and "-" indicate the same range of two numerical values, and the range includes the endpoints. For example: "A-B" means a range of greater than or equal to A and less than or equal to B. "A to B" means a range of not less than A and not more than B.

In the description of the embodiments of the present invention, the term "and/or" herein is only one kind of association relationship describing an associated object, and means that there may be three kinds of relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The above description is only a preferred embodiment of the present invention, and the technical solutions that achieve the objects of the present invention by basically the same means are all within the protection scope of the present invention.

Claims (9)

Translated fromChinese

1.一种含抗氧化复合涂层的钼合金，其特征在于，包含钼合金基体及其表面的复合涂层，所述复合涂层至少包含(Mo,X)Si₂相和(Cr,X)Si₂相。1. A molybdenum alloy containing an anti-oxidation composite coating, characterized in that it comprises a molybdenum alloy matrix and a composite coating on its surface, the composite coating comprising at least (Mo,X)Si phase and (Cr,X₎ ) Si₂ phase.2.根据权利要求1所述的一种含抗氧化复合涂层的钼合金，其特征在于，所述复合涂层为双层结构，外层至少包含(Mo,X)Si₂相和(Cr,X)Si₂相，内层至少包含(Mo,X)₅Si₃相。2 . The molybdenum alloy containing an anti-oxidation composite coating according to claim 1 , wherein the composite coating has a double-layer structure, and the outer layer at least comprises (Mo,X)Si₂ phase and (Cr) 2 . ,X)Si₂ phase, and the inner layer contains at least (Mo,X)₅ Si₃ phase.3.根据权利要求2所述的一种含抗氧化复合涂层的钼合金，其特征在于，所述外层和/或内层还包括Al₂O₃相，所述(Mo,X)Si₂中X代表Cr、Ti或W，(Cr,X)Si₂中X代表Mo、Ti或W。3. The molybdenum alloy containing an anti-oxidation composite coating according to claim 2, wherein the outer layer and/or the inner layer further comprises Al₂ O₃ phase, the (Mo,X)Si X in₂ represents Cr, Ti or W, and X in (Cr,X)Si₂ represents Mo, Ti or W.4.根据权利要求1所述的一种含抗氧化复合涂层的钼合金，其特征在于，所述钼合金基体包含以下成分：10～30at％Cr，0～15at％Al，0～30at％W，0～15at％Ti，余量为Mo。4. The molybdenum alloy containing an anti-oxidation composite coating according to claim 1, wherein the molybdenum alloy matrix comprises the following components: 10-30 at% Cr, 0-15 at% Al, 0-30 at% W, 0 to 15 at% Ti, and Mo as the remainder.5.一种含抗氧化复合涂层的钼合金的制备方法，其特征在于，具体包含以下步骤：5. a preparation method of the molybdenum alloy containing anti-oxidation composite coating, is characterized in that, specifically comprises the following steps:步骤一：Mo粉、Cr粉，Al粉，W粉，Ti粉按比例进行配料，放入球磨机中进行球磨，烘干，然后将烘干后的粉末依序进行压制成型，低压烧结，制得钼合金基体；Step 1: Mo powder, Cr powder, Al powder, W powder, and Ti powder are proportioned according to the proportion, put into a ball mill for ball milling, and dried, and then the dried powder is pressed and molded in sequence, and sintered at low pressure to obtain Molybdenum alloy matrix;步骤二：将步骤一所述的钼合金基体进行打磨、抛光、抛光及清洗后，置于管式炉中，向炉管内通入NH₃，流量为100～300ml/min，在800～1200℃下保温2～5h后随炉冷却；Step 2: After grinding, polishing, polishing and cleaning the molybdenum alloy substrate described in Step 1, place it in a tube furnace, and pass NH₃ into the furnace tube at a flow rate of 100-300ml/min, at 800-1200°C Incubate for 2 to 5 hours and then cool down with the furnace;步骤三：将硅粉、氟化钠粉、氟硅酸钠粉和氧化铝粉按一定比例混合后，球磨得到渗剂粉料；Step 3: after mixing silicon powder, sodium fluoride powder, sodium fluorosilicate powder and alumina powder according to a certain proportion, ball milling to obtain penetration agent powder;步骤四：步骤三所得的渗剂粉料装入氧化铝坩埚中，并将步骤一所得钼合金基体埋于步骤三所得的渗剂粉料中，盖上坩埚盖并用Al₂O₃粉与硅溶胶调配的料浆进行密封；将密封后的坩埚置于高温管式炉中，在氩气保护下加热至1000～1300℃保温15～30h后，随炉冷却，得到含复合涂层的钼合金。Step 4: The infiltration powder obtained in step 3 is loaded into an alumina crucible, and the molybdenum alloy matrix obtained in step 1 is buried in the infiltration powder obtained in step 3, and the crucible is covered with Al₂ O₃ powder and silicon. The slurry prepared by the sol is sealed; the sealed crucible is placed in a high-temperature tube furnace, heated to 1000-1300 °C for 15-30 hours under the protection of argon, and then cooled with the furnace to obtain a molybdenum alloy containing a composite coating .6.根据权利要求5所述的一种含抗氧化复合涂层的钼合金的制备方法，其特征在于，所述步骤一中，球磨的具体条件为：球料比5～10:1，转速100～200r/min，球磨时间10～40h。6 . The preparation method of a molybdenum alloy containing an anti-oxidation composite coating according to claim 5 , wherein, in the step 1, the specific conditions of the ball milling are: 100～200r/min, ball milling time 10～40h.7.根据权利要求5所述的一种含抗氧化复合涂层的钼合金的制备方法，其特征在于，所述步骤一中，低压烧结的温度为1600～1800℃，保温2～5h。7 . The method for preparing a molybdenum alloy containing an anti-oxidation composite coating according to claim 5 , wherein, in the first step, the temperature of low pressure sintering is 1600-1800° C., and the temperature is kept for 2-5 hours. 8 .8.根据权利要求5所述的一种含抗氧化复合涂层的钼合金的制备方法，其特征在于，所述步骤三中，所述渗剂粉料采用以下质量分数的的原料进行球磨混匀制得：硅粉20～30％，氟化钠粉2～6％，氟硅酸钠粉1～3％，氧化铝粉56～70％，还包括氧化钇粉0～5％。8. The preparation method of a molybdenum alloy containing an anti-oxidation composite coating according to claim 5, wherein in the step 3, the infiltrating agent powder is ball-milled and mixed with the raw materials of the following mass fractions Homogeneous preparation: silicon powder 20-30%, sodium fluoride powder 2-6%, sodium fluorosilicate powder 1-3%, alumina powder 56-70%, and yttrium oxide powder 0-5%.9.根据权利要求5所述的一种含抗氧化复合涂层的钼合金的制备方法，其特征在于，所述步骤三中，球磨具体为通过行星式球磨机在100～250r/min下进行球磨1～3h。9 . The method for preparing a molybdenum alloy containing an anti-oxidation composite coating according to claim 5 , wherein in the step 3, the ball milling is specifically carried out by a planetary ball mill at 100-250 r/min. 10 . 1 to 3 hours.

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