A si-based bond coat spray powder containing a release stabilizer and a method of making the same

Abstract

The application discloses a Si-based bonding layer spraying powder containing a slow-release stabilizer and a preparation method thereof, and belongs to the field of powder processing technology. The Si-based bonding layer spraying powder containing the slow-release stabilizer has a compact structure in an equiaxed shape, the length-width ratio of the equiaxed shape is 1-2, the compactness is greater than 95%, and the particle size of the Si-based bonding layer spraying powder containing the slow-release stabilizer is 5-135 microns. The powder preparation method comprises the following steps: step one, uniformly mixing Si powder and slow-release stabilizer powder; step two, performing ultrasonic melting treatment on the uniformly mixed powder; step three, preparing the powder by adopting a melting atomization method on the melted powder in step two; and screening and shaping to obtain the Si-based bonding layer spraying powder containing the slow-release stabilizer. The Si-based bonding layer spraying powder containing the slow-release stabilizer prepared by the application has the advantages that the slow-release stabilizer is uniformly dispersed and the particle size is consistent.

Description

Technical Field

[0001] The invention belongs to the technical field of powder processing, and particularly relates to a Si-based bonding layer spray powder containing a slow-release stabilizer and a preparation method thereof. Background Art

[0002] The hot-end components of aircraft engines are subjected to harsh environments characterized by high temperatures, high pressures, and high erosion. As thrust-to-weight ratios continue to increase, service temperatures have exceeded the melting point of Ni-based superalloys. For example, the inlet temperature of a turbine engine with a thrust-to-weight ratio of 10 has reached 1577°C to 1707°C, while the service temperature of Ni-based superalloys is only 1050°C. Even with film cooling technology, their temperature resistance still falls short of service requirements. Ceramic matrix composites (CMCs) with SiC or SiN matrices offer high-temperature resistance and high specific strength, and have been used in the hot-end components of aircraft engines. At high temperatures, CMCs form a protective SiO2 film on their surface. However, fuel combustion generates water vapor, which can severely corrode the SiO2 and the matrix, leading to rapid component failure.

[0003] Environmental barrier coatings (EBCs) form a barrier on hot-end components, preventing corrosion from water vapor and oxygen, effectively extending the service life of aircraft engines. EBCs generally consist of a bonding layer, an intermediate layer, and a surface layer. Currently, silicon is commonly used as the bonding layer, mullite as the intermediate layer, and a rare earth silicate as the surface layer. The silicon bonding layer has a thermal expansion coefficient similar to that of the substrate and a certain degree of resistance to water and oxygen corrosion. However, during service, oxygen penetrating from the outside will oxidize the bonding layer, forming a layer of thermally generated oxide (TGO) between the bonding layer and the intermediate layer. This volume change can cause the EBCs to peel and fail.

[0004] The material currently used in the bonding layer is pure Si, which has a weak barrier to oxygen and is easily oxidized. If it can be modified to reduce its oxidation rate or the production of phase-change oxidation products, it will help improve the service performance of EBCs.

[0005] The existing technology uses ultrasonic treatment to evenly disperse solid slow-release stabilizer particles in the Si-based melt. If the powder is not mixed evenly or the two-phase co-deposition is not evenly distributed, the generated powder will separate into two phases, affecting the uniformity of the powder and thus the performance of the coating sprayed with the powder. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a Si-based bonding layer spray powder containing a slow-release stabilizer and a preparation method thereof, so as to solve the problem in the prior art that the two phases of the prepared powder are separated by ultrasonic treatment of the powder, thereby affecting the performance of the coating formed by powder spraying.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention discloses a method for preparing a Si-based adhesive layer spray powder containing a slow-release stabilizer, which is specifically carried out according to the following steps:

[0009] Step 1: Evenly mix Si powder and slow-release stabilizer powder; wherein the slow-release stabilizer is Al2O3, or a mixture of Al2O3 and A2O3, and A in the A2O3 is Y, Fe, Co, or Ce with a valence of +3;

[0010] Step 2: ultrasonically melting the uniformly mixed powder;

[0011] Step 3: The molten powder in step 2 is subjected to melt atomization and sieving and shaping to obtain Si-based bonding layer spray powder containing a slow-release stabilizer.

[0012] Preferably, the particle size of the sustained-release stabilizer is 30-100 nm or 150-500 nm.

[0013] Preferably, in step 1, the molar number of the +3-valent metal ion in the sustained-release stabilizer is 5% to 35% of the molar number of the Si powder.

[0014] Preferably, in step 1, the mixing is carried out uniformly by ball milling or manual mixing.

[0015] Further preferably, the ball-to-material ratio in the ball milling mixture is 1:1, the rotation speed is 200 rpm, and the time is 12 hours.

[0016] Preferably, in step 2, the ultrasonication time is 30 to 60 minutes.

[0017] Preferably, in step 2, the melting heating temperature is 1430-1500° C., and the heating rate is 8-12° C. / min.

[0018] Preferably, in step three, the gas pressure for atomization by melt atomization is between 0.2 and 0.35 MPa.

[0019] The present invention also discloses a Si-based bonding layer spray powder containing a sustained-release stabilizer prepared by the above-mentioned preparation method. The Si-based bonding layer spray powder containing a sustained-release stabilizer has an equiaxed dense structure, an aspect ratio of the equiaxed shape of 1 to 2, a density >95%, and a powder particle size of 5 to 135 μm of the sustained-release stabilizer discretely distributed in the base phase Si.

[0020] The present invention also discloses the application of the Si-based bonding layer spraying powder containing a slow-release stabilizer to the bonding layer of a multi-layer environmental barrier coating on the surface of a ceramic-based composite material.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention discloses a method for preparing a Si-based bonding layer spray powder containing a slow-release stabilizer. By adding a slow-release stabilizer to Si powder, mixing the powder uniformly, and then subjecting it to ultrasonic melting treatment, the slow-release dispersant is evenly dispersed within the Si powder. The slow-release stabilizer is evenly dispersed, with a controllable and consistent particle size, overcoming the shortcomings of conventional uneven powder mixing or uneven two-phase co-deposition. The prepared Si-based bonding layer spray powder containing a slow-release stabilizer, with the slow-release stabilizer discretely distributed within the powder, can effectively extend the service life of conventional single-phase Si bonding layers, slowing TGO growth and overcoming the destructive effects of phase transition stress on the coating.

[0023] Furthermore, when melting is performed by ultrasonic treatment, if the time is too short, uniform dispersion cannot be achieved, and if the time is too long, energy is wasted.

[0024] Furthermore, the particle size of the sustained-release stabilizer can ensure that the sustained-release stabilizer particles are evenly distributed in the multi-phase powder.

[0025] Furthermore, the molar number of the trivalent metal ion of the sustained-release stabilizer can ensure that the sustained-release stabilizer plays a sustained-release stabilizing role. If the molar number is too low, the sustained-release stabilizing role is limited. If the molar number is too high, the thermal expansion coefficient of the powder will change too much, and the thermal mismatch between the sprayed coating and the substrate will be too large.

[0026] Furthermore, the base phase of the composite powder is Si, and the slow-release stabilizer is the second phase. The selected temperature is higher than the melting point of Si but lower than the melting point of the slow-release stabilizer, so as to obtain a melt with a discrete distribution of the slow-release stabilizer, thereby preparing for an equiaxed powder. The heating rate is used to gradually melt the powder. If it is too slow, the low-temperature stage will be too long and the powder will be severely oxidized. If it is too fast, the heating will be uneven and the temperature control will be inaccurate.

[0027] Furthermore, the gas pressure of the melt atomization method can ensure the shape and particle size distribution of the powder of the slow-release stabilizer discretely distributed in the base phase Si.

[0028] The present invention also discloses a Si-based bonding layer spray powder containing a slow-release stabilizer. Compared with the prior art, the slow-release stabilizer is dispersed evenly in the composite powder produced by the present invention, whereas the slow-release stabilizer is dispersed evenly in the powder of the base phase Si. Thus, the sprayed coating can maximize the discrete slow-release stabilizing effect of the slow-release stabilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of Si-based bonding layer spray powder containing slow-release stabilizer. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] Example 1

[0033] Step 1: Mix Si powder and Al2O3 powder evenly. The mixing method can be ball milling or manual mixing. The molar number of Al2O3 powder is 5% of Si powder. The ball milling process is selected as follows: ball-to-material ratio is 1:1, rotation speed is 200 rpm, and duration is 12 hours.

[0034] Step 2: Heat the evenly mixed powder so that the mixed powder is melted by heat, but only the Si powder is completely melted, and the Al2O3 powder still maintains its complete structure. The heating temperature is 1430℃, the heating rate is 8℃ / min, and the Al2O3 powder particles are evenly dispersed in the Si melt, and the Al2O3 powder does not segregate. This purpose can be achieved by subjecting the melt to 47KHz ultrasonic treatment for 30min.

[0035] Step 3: The melted and evenly mixed powder of step 2 is subjected to a powder making process, and a powder is prepared by a melt atomization method, and the atomization gas pressure is 0.2 MPa; the powder is screened and shaped to remove the satellite particles on the surface of the large particle powder, or to remove the sharp edges and corners on the surface of the particles, to obtain a powder with a discrete distribution of sustained-release stabilizer in the base phase Si with an aspect ratio of 1, the powder particle size is 5 μm, and the overall structure is dense, such as Figure 1 As shown, the sustained-release stabilizer is uniformly dispersed in the Si powder.

[0036] Example 2

[0037] Step 1: Mix Si powder, Al2O3 powder and Y2O3 powder evenly, with the molar ratio of Al2O3 powder to Y2O3 powder being 1:1. The mixing method can be ball milling or manual mixing, wherein the total molar number of Al2O3 powder and Y2O3 powder is 10% of Si powder. The ball milling process is selected as follows: ball-to-material ratio is 1:1, rotation speed is 200 rpm, and duration is 12 hours;

[0038] Step 2: Heat the mixed powders until the mixed powders are melted, but only the Si powder is completely melted, while the Y2O3 powder still maintains its intact structure. The heating temperature is 1440°C, the heating rate is 10°C / min, and the Y2O3 powder particles are evenly dispersed in the Si melt without segregation of the Y2O3 powder. This can be achieved by subjecting the melt to 47KHz ultrasonic treatment for 35min.

[0039] Step three, the melted and evenly mixed powder of step two is subjected to powder making treatment, and the powder is prepared by melt atomization method. The atomization gas pressure is 0.25 MPa. The powder is screened and shaped to remove the satellite particles on the surface of the large particles or the sharp edges on the surface of the particles to obtain a powder with a discrete distribution of sustained-release stabilizer in the base phase Si with an aspect ratio of 2, and the powder particle size is 15 μm.

[0040] Example 3

[0041] Step 1: Mix Si powder, Al2O3 powder and Fe2O3 powder evenly. The mixing method can be ball milling or manual mixing. The molar number of Al2O3 powder and Fe2O3 powder is 20% of Si powder. The ball milling process is selected as follows: ball-to-material ratio is 1:1, the speed is 200 rpm, and the mixing time is 12 hours.

[0042] Step 2: Heat the mixed powders until the mixed powders are melted, but only the Si powder is completely melted, while the Fe2O3 powder still maintains its intact structure. The heating temperature is 1450°C, the heating rate is 12°C / min, and the Fe2O3 powder particles are evenly dispersed in the Si melt without segregation of the Fe2O3 powder. This can be achieved by subjecting the melt to 47KHz ultrasonic treatment for 40min.

[0043] Step three, the melted and evenly mixed powder of step two is subjected to powder making treatment, and the powder is prepared by melt atomization method. The atomization gas pressure is 0.29 MPa. The powder is screened and shaped to remove the satellite particles on the surface of the large particles or the sharp edges on the surface of the particles to obtain a powder with a discrete distribution of sustained-release stabilizer in the base phase Si with an aspect ratio of 1.5, and the powder particle size is 50 μm.

[0044] Example 4

[0045] Step 1: Mix Si powder, Al2O3 powder and Co2O3 powder evenly. The mixing method can be ball milling or manual mixing. The molar number of Al2O3 powder and Co2O3 powder is 25% of Si powder. The ball milling process is selected as follows: ball-to-material ratio is 1:1, the speed is 200 rpm, and the mixing time is 12 hours.

[0046] Step 2: Heat the mixed powder until the mixed powder is melted, but only the Si powder is completely melted, and the Co2O3 powder still maintains its intact structure. The heating temperature is 1470°C, the heating rate is 10°C / min, and the Co2O3 powder particles are evenly dispersed in the Si melt, and the Co2O3 powder does not segregate. This can be achieved by subjecting the melt to 47KHz ultrasonic treatment for 50min.

[0047] Step three, the melted and evenly mixed powder of step two is subjected to powder making treatment, and the powder is prepared by melt atomization method. The atomization gas pressure is 0.32MPa. The powder is screened and shaped to remove the satellite particles on the surface of the large particles or the sharp edges on the surface of the particles to obtain a powder with a discrete distribution of sustained-release stabilizer in the base phase Si with an aspect ratio of 2, and the powder particle size is 90μm.

[0048] Example 5

[0049] Step 1: Mix Si powder, Al2O3 powder and Ce2O3 powder evenly. The mixing method can be ball milling or manual mixing. The molar number of Al2O3 powder and Ce2O3 powder is 35% of Si powder. The ball milling process is selected as follows: ball-to-material ratio is 1:1, rotation speed is 200 rpm, and duration is 12 hours;

[0050] Step 2: Heat the mixed powder until the mixed powder is melted, but only the Si powder is completely melted, and the Ce2O3 powder still maintains its complete structure. The heating temperature is 1500℃, the heating rate is 10℃ / min, and the Ce2O3 powder particles are evenly dispersed in the Si melt, and the Ce2O3 powder does not segregate. This can be achieved by subjecting the melt to 47KHz ultrasonic treatment for 60min.

[0051] Step three, the melted and evenly mixed powder of step two is subjected to powder making treatment, and the powder is prepared by melt atomization method. The atomization gas pressure is 0.35 MPa. The powder is screened and shaped to remove the satellite particles on the surface of the large particles or the sharp edges on the surface of the particles to obtain a powder with a discrete distribution of sustained-release stabilizer in the base phase Si with an aspect ratio of 2, and the powder particle size is 135 μm.

[0052] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a Si-based bonding layer spray powder containing a slow-release stabilizer, characterized in that: Follow these steps: Step 1: Evenly mix Si powder and a sustained-release stabilizer powder having a particle size of 30-100 nm or 150-500 nm; wherein the sustained-release stabilizer is Al2O3, or a mixture of Al2O3 and A2O3, and A in the A2O3 is Y, Fe, Co, or Ce with a valence of +3; Step 2: ultrasonically melt the uniformly mixed powder at a melting temperature of 1430-1500°C and a heating rate of 8-12°C / min; Step 3: The melted powder in step 2 is subjected to melt atomization and sieving and shaping, with the gas pressure of the melt atomization method being 0.2-0.35 MPa, to obtain a Si-based bonding layer spray powder containing a slow-release stabilizer; Among them, the Si-based bonding layer spray powder containing a slow-release stabilizer has an equiaxed dense structure with an aspect ratio of 1 to 2 and a density of >95%. The powder particle size of the slow-release stabilizer discretely distributed in the base phase Si is 5 to 135 μm.

2. The method for preparing a Si-based bonding layer spray powder containing a slow-release stabilizer according to claim 1, characterized in that: In step 1, the molar number of the +3-valent metal ion in the sustained-release stabilizer is 5% to 35% of the molar number of the Si powder.

3. The method for preparing a Si-based bonding layer spray powder containing a slow-release stabilizer according to claim 1, characterized in that: In step 1, the mixing is carried out by either ball milling or manual mixing.

4. The method for preparing a Si-based bonding layer spray powder containing a slow-release stabilizer according to claim 3, characterized in that: The ball-to-material ratio in the ball milling mixture was 1:1, the rotation speed was 200 rpm, and the time was 12 h.

5. The method for preparing a Si-based adhesive layer spray powder containing a slow-release stabilizer according to claim 1, characterized in that: In step 2, the ultrasonication time is 30 to 60 minutes.

6. The Si-based adhesive layer spray powder containing a slow-release stabilizer prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the Si-based bonding layer spray powder containing a slow-release stabilizer according to claim 6 in preparing a bonding layer of a multi-layer environmental barrier coating on the surface of a ceramic-based composite material.

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