A si-based environmental barrier coating layer containing a discrete distribution of a release stabilizer

Abstract

The application discloses a Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers and belongs to the technical field of coating. The application comprises the following steps: step one, cleaning the surface of a ceramic matrix composite workpiece; step two, preheating the ceramic matrix composite workpiece; step three, uniformly mixing Si powder and slow-release stabilizers; ultrasonic melting treatment is performed on the uniformly mixed powder; the melted powder is prepared into spraying powder by adopting a melting atomization method and screening and shaping; step four, the spraying powder is added into a bin and is sprayed on the surface of the preheated ceramic matrix composite workpiece by adopting vacuum plasma spraying, and spraying is performed in an Ar and He gas environment, so that the Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers is obtained. The application reduces the growth rate of TGO and inhibits the phase change of TGO at 220 DEG C by introducing the slow-release stabilizers which are discretely distributed in the bonding layer, slows down the peeling of the surface layer, and prolongs the service life of the environmental barrier coating.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating, and particularly relates to a Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers. BACKGROUND

[0002] Environmental barrier coatings (EBCs) are currently widely used in the surface of ceramic matrix composites (CMC) in aero-engines and gas turbines to resist water-oxygen corrosion caused by high oxygen partial pressure and moisture pressure in high-temperature environments. In order to improve the protective performance and adjust the thermal mismatch between the surface layer and the substrate, the current environmental barrier coating is mostly a multilayer structure, that is, the inner layer is a bonding layer, and the outer layer is a protective layer.

[0003] The commonly used bonding layer is pure Si, which can better bond the substrate and the outer layer, and at the same time has a certain water-oxygen corrosion resistance. However, the thermal generated oxide (TGO) will be generated between the Si bonding layer and the surface layer during service, which produces thermal stress, and at the same time, the phase transition of TGO at 220 DEG C produces phase transition stress, and the oxygen resistance ability of TGO itself is weak, the existence of the two kinds of stress will cause the peeling of the surface layer, and then cause the failure of EBCs. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers, which solves the problem of failure of environmental barrier coating caused by thermal stress and phase transition stress in the prior art.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application discloses a preparation method of a Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers, comprising the following steps:

[0007] Step one, cleaning the surface of the ceramic matrix composite workpiece;

[0008] Step two, preheating treatment of the ceramic matrix composite workpiece;

[0009] Step three, uniformly mixing Si powder and slow-release stabilizers; ultrasonic melting treatment is performed on the uniformly mixed powder; the melted powder is prepared into a spraying powder by using a melting and atomizing method and screening and shaping;

[0010] Step four, adding the spraying powder into a hopper, and spraying on the surface of the preheated ceramic matrix composite workpiece by using vacuum plasma spraying in an Ar and He gas environment to obtain a Si-based environmental barrier bonding layer containing discrete distribution of slow-release stabilizers.

[0011] Preferably, the slow-release stabilizer is Al2O3 or a mixture of Al2O3 and A2O3, wherein A is a +3 valence metal ion, and A is Y, Fe, Co or Ce.

[0012] Further preferably, the number of moles of metal ions in the slow-release stabilizer is 5% to 25% of the number of moles of silicon.

[0013] Preferably, the particle size of the slow-release stabilizer is any one of 30 to 100 nm or 150 to 500 nm, and the slow-release stabilizer is an equiaxial shape with an aspect ratio of 1 to 2.

[0014] Preferably, the surface cleaning in step one is oil removal and sand blasting, and the oil removal is selected from alkali solution oil removal, organic solvent oil removal, metal cleaner oil removal or electrochemical oil removal; the roughness after sand blasting treatment is 5 to 8 Ra.

[0015] Preferably, the preheating temperature in step two is 800 to 1200℃, and the heating temperature in step three is 1430 to 1500℃.

[0016] Preferably, the flow rate of Ar gas is 40 to 70 L / min, the flow rate of He gas is 2 to 5 L / min, the arc voltage of the spraying equipment is 40 to 55 V, the current is 600 to 850 A, the powder feeding speed is 20 to 40 g / min, and the spraying distance is 200 to 300 mm.

[0017] The application also discloses a Si-based environmental barrier bonding layer containing the slow-release stabilizer prepared by the preparation method, wherein the Si-based environmental barrier bonding layer containing the slow-release stabilizer is a dual-phase structure of a Si-based phase and a granular slow-release stabilizer; the Si-based phase is a dense structure with a density of greater than or equal to 95%; and the degree of adjacency between the slow-release stabilizer particles is less than 0.3.

[0018] Preferably, the thickness is 80 to 120 μm.

[0019] The application also discloses application of the Si-based environmental barrier bonding layer containing the slow-release stabilizer to a multilayer environmental barrier coating.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] The application provides a preparation method of a Si-based environmental barrier bonding layer containing a discrete distribution of slow-release stabilizers, which is used for cleaning the surface of a ceramic matrix composite workpiece, can make the prepared spraying powder have stronger bonding force with the surface of the ceramic matrix composite workpiece, can improve the density of the coating through preheating treatment, and has the advantages of less substrate heating, faster spraying speed and less oxidation of the spraying powder. In order to improve the internal stress problem caused by the generation and growth of thermal generated oxides on the traditional environmental barrier coating Si bonding layer, the slow-release stabilizers are introduced into the bonding layer in a discrete distribution to reduce the growth rate of TGO and inhibit the phase change of TGO at 220 DEG C, so that the obtained Si-based environmental barrier bonding layer containing the discrete distribution of slow-release stabilizers can slow down the peeling of the surface layer and prolong the service life of the environmental barrier coating.

[0022] Further, the slow-release stabilizer is a trivalent metal ion oxide, the trivalent metal ion dopes the thermal generated oxide, i.e. SiO2, to reduce the growth rate and hinder the diffusion of oxygen.

[0023] Further, when the content of the slow-release stabilizer is less than 5%, the effect of hindering the growth of TGO is too weak, and when the content is higher than 25%, the thermal expansion coefficient of the whole bonding layer is increased too much, which affects the thermal matching of the bonding layer and the substrate, causes thermal stress in the thermal cycle process, and causes the peeling of the coating. The slow-release stabilizer does not have a chemical reaction with Si, the slow-release stabilizer particles in the bonding layer are preferentially dispersed at the grain boundaries of the bonding layer base phase, can prevent the diffusion of water and oxygen along the grain boundaries, and prolong the service life of the coating.

[0024] Further, the smaller the slow-release stabilizer is, the smaller the distance between the slow-release stabilizer particles is at the same volume fraction, and the better the protection effect on the substrate is, but too small particle size can cause the slow-release stabilizer to agglomerate, and the temperature drops too fast in the spraying process, which affects the density of the whole coating. The particle size of the Si powder is to ensure the spraying quality.

[0025] Further, the purpose of preheating is to make the sprayed coating dense, the porosity of the coating is too large at too low temperature, and the thermal deformation of the workpiece is too large at too high temperature.

[0026] Further, the slow-release stabilizer is a fine particle in a dispersed distribution, and the adjacency degree is less than 0.3, which can more effectively protect the whole bonding layer.

[0027] Further, in order to make the coating and the substrate well combined, sand blasting roughening treatment is performed, and the surface roughness in the range is selected to match the particle size of the spraying powder. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A sectional view of the Si-based environmental barrier bonding layer containing a discrete distribution of slow-release stabilizers prepared by using the plasma spraying technology;

[0029] Figure 2 For Figure 1 Enlarged view of site A.

[0030] Wherein, 1, ceramic matrix composite workpiece; 2, Si-based adhesive layer containing discrete distribution of slow-release stabilizer; 3, Si particles; 4, slow-release stabilizer particles. DETAILED DESCRIPTION

[0031] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0032] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. 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 have to be limited to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0033] Embodiment 1

[0034] The preparation method of the Si-based environmental barrier adhesive layer containing discrete distribution of slow-release stabilizer is characterized by the following steps:

[0035] Step one, clean the surface of the ceramic matrix composite workpiece; the surface of the ceramic matrix composite workpiece is treated for oil removal, oxide removal, and adhesion removal, the oil removal is soaked in 3 mol / L NaOH solution for 30 min, then the surface is dried, and the surface oxide and adhesion are removed by sand blasting, so that the roughness after treatment is 5.0;

[0036] Step two, preheat the ceramic matrix composite workpiece; the preheating temperature is 800℃;

[0037] Step three, uniformly mix Si powder and Al2O3 with a particle size of 30 nm, the mole number of Al is 5% of the mole number of Si; ultrasonic melting treatment is performed on the uniformly mixed powder, the heating temperature for melting is 1430 DEG C; the melted powder is prepared into a spraying powder by using a melting atomization method and screening and shaping;

[0038] Step four, the spraying powder is added into a bin and is sprayed on the surface of the ceramic matrix composite workpiece after preheating treatment by using vacuum plasma spraying, the spraying is performed in an Ar and He gas environment, the flow rate of Ar gas is 40 L / min, the flow rate of He gas is 2 L / min, the arc voltage of the spraying equipment is 40 V, the current is 600 A, the powder feeding speed is 20 g / min, the spraying distance is 200 mm, and a Si-based environmental barrier bonding layer with a thickness of 80 μm and a dense structure and containing a discrete distribution of a slow-release stabilizer is obtained, as shown in Figure 1 and Figure 2 .

[0039] Example 2

[0040] A preparation method of a Si-based environmental barrier bonding layer containing a discrete distribution of a slow-release stabilizer, characterized in that the following steps are performed:

[0041] Step one, clean the surface of the ceramic matrix composite workpiece; perform oil removal, oxide skin removal and adhesive removal treatment on the surface of the ceramic matrix composite workpiece, immerse in 4 mol / L NaOH solution for 30 min for oil removal, then dry the surface, and remove the surface oxide skin and adhesive by using sand blasting, so that the roughness after treatment is 6.0;

[0042] Step two, preheat the ceramic matrix composite workpiece; the preheating temperature is 900 DEG C;

[0043] Step three, uniformly mix Si powder and Al2O3 powder and Y2O3 powder with a particle size of 100 nm, the mole number of Al and Y is 10% of the mole number of Si; ultrasonic melting treatment is performed on the uniformly mixed powder, the heating temperature for melting is 1430 DEG C; the melted powder is prepared into a spraying powder by using a melting atomization method and screening and shaping;

[0044] Step four, the spraying powder is added into a bin and is sprayed on the surface of the ceramic matrix composite workpiece after preheating treatment by using vacuum plasma spraying, the spraying is performed in an Ar and He gas environment, the flow rate of Ar gas is 45 L / min, the flow rate of He gas is 2.5 L / min, the arc voltage of the spraying equipment is 45 V, the current is 700 A, the powder feeding speed is 30 g / min, the spraying distance is 250 mm, and a Si-based environmental barrier bonding layer with a thickness of 90 μm and a dense structure and containing a discrete distribution of a slow-release stabilizer is obtained.

[0045] Example 3

[0046] The preparation method of the Si-based environmental barrier bonding layer containing the discrete distribution of the slow-release stabilizer is characterized in that the following steps are specifically performed:

[0047] Step one, cleaning the surface of the ceramic matrix composite workpiece; the surface of the ceramic matrix composite workpiece is treated for oil removal, oxide skin removal, and adhesion removal, oil removal is selected by immersing in a 4 mol / L NaOH solution for 40 min, then drying the surface, and using sand blasting to remove the surface oxide skin and adhesion, so that the roughness after treatment is 6.5;

[0048] Step two, preheating the ceramic matrix composite workpiece; the preheating temperature is 950°C;

[0049] Step three, uniformly mixing Si powder with Al2O3 powder and Fe2O3 powder with a particle size of 150 nm, the mole number of Al and Fe is 10% of the mole number of Si; the uniformly mixed powder is treated by ultrasonic melting, the heating temperature for melting is 1450°C; the melted powder is prepared into a spraying powder by using a melting atomization method and screening and shaping;

[0050] Step four, adding the spraying powder into the bin and using vacuum plasma spraying on the surface of the preheated ceramic matrix composite workpiece, spraying in an Ar and He gas environment, the flow rate of the Ar gas is 60 L / min, the flow rate of the He gas is 4 L / min, the arc voltage of the spraying equipment is 50 V, the current is 750 A, the powder feeding speed is 35 g / min, the spraying distance is 280 mm, and a dense structure Si-based environmental barrier bonding layer containing the discrete distribution of the slow-release stabilizer with a thickness of 100 μm is obtained.

[0051] Example 4

[0052] The preparation method of the Si-based environmental barrier bonding layer containing the discrete distribution of the slow-release stabilizer is characterized in that the following steps are specifically performed:

[0053] Step one, cleaning the surface of the ceramic matrix composite workpiece; the surface of the ceramic matrix composite workpiece is treated for oil removal, oxide skin removal, and adhesion removal, oil removal is selected by immersing in a 4 mol / L NaOH solution for 50 min, then drying the surface, and using sand blasting to remove the surface oxide skin and adhesion, so that the roughness after treatment is 7.5;

[0054] Step two, preheating the ceramic matrix composite workpiece; the preheating temperature is 1100°C;

[0055] Step three, Si powder and Al2O3 powder and Co2O3 powder with a particle size of 300 nm are mixed uniformly, the mole number of Al and Co is 20% of the mole number of Si; the uniformly mixed powder is subjected to ultrasonic melting treatment, the heating temperature of melting is 1480℃; the melted powder is prepared into a spraying powder by using a melting atomization method and screening and shaping;

[0056] Step four, the spraying powder is added into a bin and is sprayed on the surface of the ceramic matrix composite workpiece after preheating treatment by using vacuum plasma spraying, the spraying is carried out in an Ar and He gas environment, the flow rate of Ar gas is 50L / min, the flow rate of He gas is 3L / min, the arc voltage of the spraying equipment is 50V, the current is 800A, the powder feeding speed is 40g / min, the spraying distance is 260mm, and a Si-based environmental barrier bonding layer with a thickness of 110μm and a compact structure and containing a discrete distribution of a slow-release stabilizer is obtained.

[0057] Example 5

[0058] A preparation method of a Si-based environmental barrier bonding layer containing a discrete distribution of a slow-release stabilizer, characterized in that the following steps are carried out:

[0059] Step one, the surface of the ceramic matrix composite workpiece is cleaned; the surface of the ceramic matrix composite workpiece is treated for oil removal, oxide skin removal and adhesion removal, the oil removal is carried out by immersing in a 3mol / L NaOH solution for 60min, then the surface is dried, and the surface oxide skin and adhesion are removed by sand blasting, so that the roughness after treatment is 8.0;

[0060] Step two, the ceramic matrix composite workpiece is subjected to preheating treatment; the preheating temperature is 1200℃;

[0061] Step three, Si powder and Al2O3 powder and Ce2O3 with a particle size of 500 nm are mixed uniformly, the mole number of Al and Ce is 25% of the mole number of Si; the uniformly mixed powder is subjected to ultrasonic melting treatment, the heating temperature of melting is 1500℃; the melted powder is prepared into a spraying powder by using a melting atomization method and screening and shaping;

[0062] Step four, the spraying powder is added into a bin and is sprayed on the surface of the ceramic matrix composite workpiece after preheating treatment by using vacuum plasma spraying, the spraying is carried out in an Ar and He gas environment, the flow rate of Ar gas is 70L / min, the flow rate of He gas is 5L / min, the arc voltage of the spraying equipment is 55V, the current is 850A, the powder feeding speed is 40g / min, the spraying distance is 300mm, and a Si-based environmental barrier bonding layer with a thickness of 120μm and a compact structure and containing a discrete distribution of a slow-release stabilizer is obtained.

[0063] The above merely illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A method for preparing a Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer, characterized in that: The following steps are involved: Step 1: Cleaning the surface of the ceramic matrix composite workpiece; Step 2: preheating the ceramic matrix composite material workpiece; Step 3: Mix the Si powder and the slow-release stabilizer uniformly; perform ultrasonic melting treatment on the uniformly mixed powder; and prepare a spray powder by melt atomization and screening and shaping the melted powder; The sustained-release stabilizer is Al2O3 or a mixture of Al2O3 and A2O3, A is a +3 valent metal ion, and A is Y, Fe, Co, or Ce; the particle size of the sustained-release stabilizer is any one of 30-100 nm or 150-500 nm, and the sustained-release stabilizer is equiaxed with an aspect ratio of 1-2; the molar number of the metal ion in the sustained-release stabilizer is 5%-25% of the molar number of Si; Step 4: Add the spray powder to the hopper and use vacuum plasma spraying on the surface of the ceramic matrix composite workpiece after preheating treatment in an Ar and He gas environment to obtain a Si-based environmental barrier bonding layer containing a discretely distributed slow-release stabilizer; Among them, the Si-based environmental barrier bonding layer containing discretely distributed slow-release stabilizers is a two-phase structure of discretely distributed Si-based phase and granular slow-release stabilizers; the Si-based phase is a dense structure with a density of ≥95%; and the adjacency between the slow-release stabilizer particles is less than 0.

3.

2. The method for preparing a Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer according to claim 1, wherein: Step 1: Surface cleaning includes degreasing and sandblasting. Degreasing can be done by alkali degreasing, organic solvent degreasing, metal cleaning agent degreasing or electrochemical degreasing. The roughness after sandblasting is 5~8 Ra.

3. The method for preparing a Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer according to claim 1, characterized in that: The preheating temperature in step 2 is 800~1200℃; the heating temperature for melting in step 3 is 1430~1500℃.

4. The method for preparing a Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer according to claim 1, wherein: In step 4, the flow rate of Ar gas is 40~70 L / min, the flow rate of He gas is 2~5 L / min, the arc voltage of the spraying equipment is 40~55 V, the current is 600~850 A, the powder feeding speed is 20~40 g / min, and the spraying distance is 200~300 mm.

5. The Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer prepared by the preparation method according to any one of claims 1 to 4.

6. The Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer according to claim 5, characterized in that: The thickness is 80~120 μm.

7. Use of the Si-based environmental barrier adhesive layer containing a discretely distributed slow-release stabilizer according to claim 5 or 6 in the preparation of a multi-layer environmental barrier coating.

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