A TGO-resistant HfSiO4 adhesive layer material with a coating microstructure for EBC, its preparation method and application

Abstract

The application belongs to the technical field of SiC ceramic matrix composite materials, and discloses an HfSiO4 bonding layer material with a coated microstructure for EBC and resistant to TGO corrosion, a preparation method and application thereof; the preparation method is as follows: HfO2 powder is uniformly mixed with silica sol, then wet ball milling is performed to obtain a slurry; the slurry is dried and ground to obtain a mixed powder; the mixed powder is ground after high-temperature sintering to obtain the HfSiO4 bonding layer material with the coated microstructure for EBC and resistant to TGO corrosion. The process flow of the application is simple, the process is highly feasible, and raw materials are easy to obtain; the environmental barrier coating material prepared by the application is resistant to TGO corrosion, has a thermal expansion coefficient similar to that of SiC / SiC composite material, and the thermal expansion coefficient is adjustable; the anti-dry air oxidation resistance is excellent, and the water-oxygen corrosion resistance is high.

Description

Technical Field

[0001] This invention relates to the field of SiC ceramic matrix composites, and more particularly to an EBC with a coating microstructure that is resistant to heat-grown oxide (TGO) corrosion, an HfSiO4 bonding layer, its preparation method, and its application. Background Technology

[0002] SiC / SiC composite materials are ideal high-temperature structural materials for aero-engines. The high temperature, corrosion, and exhaust erosion of aero-engines cause the surface stability of SiC / SiC composite materials to deteriorate sharply. Environmental barrier coatings (EBCs) can establish a barrier between SiC / SiC composite materials and the harsh engine environment, preventing or reducing the impact of the engine environment on high-temperature structural materials as much as possible.

[0003] Similar to thermal barrier coatings (TBCs), EBCs also require a bonding layer. This bonding layer plays a crucial role, enhancing the adhesion between the EBC surface layer and the SiC / SiC substrate, and preventing oxygen or water vapor from diffusing further through the EBC surface layer. It is an essential component of the EBC system. To date, Si and Si-HfO2 have been commonly used as bonding layers in SiC / SiC composite EBCs. However, Si bonding layers are prone to oxidation, forming thermally grown oxides (TGO, referring to SiO2 in this case), which can lead to cracks and cause EBC delamination, peeling, and failure. The Si-HfO2 binder layer uses HfO2 (up to 2800℃) with a higher melting point to modify the Si binder layer, which can improve the creep strength and high-temperature performance of the binder layer. Simultaneously, HfO2 oxidizes with Si to form SiO2, which in turn forms HfSiO4 at high temperatures. HfSiO4 itself has a thermal expansion coefficient closer to that of the SiC / SiC composite material, thus avoiding CTE mismatch. HfSiO4 has a low oxygen diffusion coefficient, effectively reducing oxygen penetration into the substrate material and suppressing TGO formation. Furthermore, the thermal expansion coefficient can be adjusted using the Si / HfO2 ratio. However, HfO2 itself is a good conductor of oxygen, which is not conducive to hindering oxygen diffusion into the matrix material; precise control of the HfO2 doping amount is difficult, and Si is at risk of further oxidation.

[0004] Therefore, some researchers have proposed using HfSiO4 directly as the bonding layer. However, there are limitations in the chemical reaction: due to thermodynamic and kinetic limitations, it is difficult to completely synthesize HfSiO4 in a 1:1 ratio during subsequent heat treatment from the spraying raw materials HfO2 and SiO2; the heat treatment time is too long (up to hundreds of hours) and micropores are easily generated; and the residual HfO2 is a good conductor of oxygen, which is not conducive to hindering the diffusion of oxygen to the substrate material.

[0005] Therefore, the present invention provides an improved scheme to prepare an EBC HfSiO4 adhesive layer material with a coating microstructure that is resistant to TGO corrosion. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention provides an EBC HfSiO4 adhesive layer material with a coating microstructure resistant to TGO corrosion, its preparation method, and its application.

[0007] The first objective of this invention is to provide a method for preparing an EBC HfSiO4 adhesive layer material with a coated microstructure that is resistant to TGO corrosion, comprising the following steps:

[0008] S1. HfO2 powder and silica sol are mixed at an Hf:Si molar ratio of 1:0.8 to 1.6 and then wet ball milled to obtain a slurry; the slurry is dried and then ground to obtain a mixed powder.

[0009] S2. The mixed powder is sintered at 1450-1600℃ and then ground into powder to obtain an EBC HfSiO4 bonding layer material with a coating microstructure that is resistant to TGO corrosion.

[0010] Preferably, the purity of the HfO2 powder is ≥99.99 wt.%; and / or, the particle size of the HfO2 powder is 3–6 μm.

[0011] Preferably, the purity of the silica sol is 25 wt.%; and / or, the particle size of SiO2 in the silica sol is 8–12 μm.

[0012] Preferably, the ball milling aid in the wet ball milling is anhydrous ethanol, and the ball milling rate is 20-60 Hz, and the ball milling time is 12-24 h.

[0013] Preferably, the drying temperature of the slurry is 60-80°C, and the drying time is 12-24 hours.

[0014] Preferably, the grinding conditions after the slurry is dried are an agate mortar and pestle, and the grinding time is 20 to 40 minutes.

[0015] Preferably, the particle size of the slurry after drying and grinding is 10-15 μm.

[0016] Preferably, the high-temperature sintering time of the mixed powder is 1 to 5 hours.

[0017] Preferably, after high-temperature sintering, the grinding conditions are an agate mortar and pestle, and the grinding time is 30-50 minutes.

[0018] Preferably, the particle size of the powder after high-temperature sintering and grinding is 40–70 μm.

[0019] Another object of the present invention is to provide an HfSiO4 bonding layer material prepared by the above method.

[0020] Another objective of this invention is to improve the application of an HfSiO4 adhesive layer material in the preparation of HfSiO4 adhesive layers.

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

[0022] This invention uses HfO2 powder and silica sol as raw materials to synthesize HfSiO4. By synthesizing HfSiO4, the environmental barrier coating material and SiC / SiC composite material can maintain good thermal expansion matching. After ball milling and sintering, a coating structure is formed to effectively delay the mass transfer process of TGO, thereby delaying the fragmentation and detachment of the entire EBC system.

[0023] The process of this invention is simple, highly feasible, and uses readily available raw materials. Furthermore, the adhesive layer material prepared by this invention is resistant to TGO corrosion, has a thermal expansion coefficient similar to that of SiC / SiC composite materials with adjustable thermal expansion coefficients, and exhibits excellent resistance to dry air oxidation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the microstructure of the adhesive layer formed by the adhesive layer material prepared in this invention.

[0025] Figure 2 The XRD patterns of the coated powder of the present invention were measured at different ratios (Hf:Si);

[0026] Figure 3 The XRD patterns of the coated powder of this invention were measured at different sintering temperatures;

[0027] Figure 4 XRD pattern of uncoated powder prepared in Comparative Example 1;

[0028] Figure 5 TEM image of the uncoated powder prepared for Comparative Example 1;

[0029] Figure 6 The XRD patterns of Comparative Example 1 were measured before and after SiO2 corrosion.

[0030] Figure 7 The XRD patterns of Example 1 before and after SiO2 etching are shown below.

[0031] Figure 8 The image is a TEM image of the coated powder prepared in Example 1. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0034] As described in the background section, common Si binders have low melting points, poor temperature resistance, poor oxidation resistance, and poor resistance to water and oxygen corrosion. While Si-HfO2 binders improve temperature resistance, the Si component still faces the risk of oxidation and water and oxygen corrosion. Furthermore, HfO2 itself is a good conductor of oxygen, which is not conducive to hindering the diffusion of oxygen into the matrix material. In addition, it is difficult to precisely control the amount of HfO2 doping. The HfSiO4 binder recently proposed by researchers has the problems of easily creating micropores inside the binder, excessively long post-processing time, and the presence of residual HfO2, which is also not conducive to hindering the diffusion of oxygen into the matrix material.

[0035] Based on this, the present invention uses silica sol as a raw material to prepare a nano-scale SiO2-coated HfO2 structure by ball milling, followed by high-temperature sintering to obtain a HfSiO4-coated HfO2 microstructure. On one hand, HfSiO4 coating HfO2 inhibits the contact between HfO2 and TGO (SiO2), thereby improving the corrosion resistance of the binder material to TGO. On the other hand, it retains the excellent properties of HfSiO4 itself, such as a thermal expansion coefficient similar to that of SiC / SiC composites and a low oxygen diffusion coefficient. Furthermore, the overall thermal expansion coefficient of the binder can be controlled by adjusting the ratio of silica sol to HfO2. The technical solutions in the embodiments of the present invention will be clearly and completely described below:

[0036] Step 1, mix all the raw materials:

[0037] HfO2 powder and silica sol are mixed at a molar ratio of HfO2 powder to SiO2 of 1:0.8 to 1.6, and then wet ball milled to obtain a slurry. The slurry is dried and then ground to obtain a mixed powder.

[0038] It should be noted that this invention uses silica sol and HfO2 powder as raw materials to synthesize HfSiO4. By synthesizing a certain amount of HfSiO4, the environmental barrier coating material and the SiC / SiC composite material can maintain good thermal expansion matching. On the basis of ensuring good thermal expansion matching between the prepared environmental barrier coating material and the SiC / SiC composite material, the bonding layer raw material is further enhanced to resist TGO corrosion by forming a coating structure.

[0039] To ensure that the overall coefficient of thermal expansion of the environmental barrier coating material finally prepared by this invention maintains good matching with that of the SiC / SiC composite material, in a preferred embodiment of this invention, HfO2 powder and silica sol are first premixed, and then anhydrous ethanol is used as a ball milling aid to ball mill the premixed HfO2 powder and silica sol mixture using a wet ball milling method. This ensures that the HfO2 powder and SiO2 powder are fully mixed and form a coating structure. Preferably, the ball milling rate of the wet ball milling is 20-60 Hz and the ball milling time is 12-24 h.

[0040] To further promote thorough mixing of HfO2 and SiO2, in a preferred embodiment of this invention, HfO2 is added in the form of high-purity powder, while the silica sol SiO2 is added in liquid form. The purity of the HfO2 powder is ≥99.99 wt.%; the particle size of the HfO2 powder is 3–6 μm. The purity of the silica sol is 25 wt.%; the particle size of the SiO2 within the silica sol is 8–12 μm.

[0041] In order to facilitate subsequent high-temperature sintering, in a preferred embodiment of the present invention, the slurry after wet ball milling is further dried to remove excess anhydrous ethanol, and the drying temperature is 60-80°C and the drying time is 12-24 hours.

[0042] To prevent material agglomeration during the drying process, which would hinder high-temperature sintering, the dried product was ground before high-temperature sintering. This ensured that the mixed powder was fully calcined in air during the high-temperature sintering process. However, to prevent other impurities from entering and affecting the subsequent high-temperature solid-state reaction, the grinding time could not be too long. In a preferred embodiment of this invention, the grinding time was 20–40 minutes.

[0043] To avoid the introduction of other impurities during the grinding process, which would be detrimental to the purity of the raw materials for the resulting bonding layer, the mortar used in the grinding process is preferably an agate mortar. The agate mortar is composed of SiO2, which can effectively prevent the introduction of other impurities.

[0044] Step 2, high-temperature sintering:

[0045] The mixed powder is sintered at high temperature and ground into powder to obtain an EBC HfSiO4 bonding layer material with a coating microstructure that is resistant to TGO corrosion.

[0046] It should be noted that, considering that solid-state reactions generally have low activity and require sufficient activation energy to begin before the reaction can start, and that solid-state reaction rates are slow and require sufficient time to proceed, in a preferred embodiment of the present invention, the sintering temperature of high-temperature sintering is 1450–1600°C and the sintering time is 1–5 h, in order to achieve the purpose of high purity and uniformity of the final product.

[0047] The TGO-resistant EBC HfSiO4 adhesive layer material with a coating microstructure obtained by this invention ultimately contains HfSiO4 and HfO2.

[0048] To enable those skilled in the art to further understand the technical solution of the present invention, the technical solution of the present invention will be further described in detail below through specific embodiments and comparative examples.

[0049] Comparative Example 1:

[0050] This comparative example provides an HfSiO4 adhesive layer material for EBC without a coating microstructure, and its preparation method is as follows:

[0051] 1) Using HfO2 powder with a particle size of 6μm and a purity of 99.99wt.% and SiO2 powder with a particle size of 8μm and a purity of 99.99wt.% as raw materials, weigh the corresponding mass of the above HfO2 powder and SiO2 powder according to the equimolar ratio of Hf:Si, and set them aside.

[0052] 2) Mix the weighed HfO2 powder and SiO2 powder to obtain a mixture; add an equal mass of anhydrous ethanol as a ball milling aid to the mixture, and ball mill at a speed of 40 Hz for 20 h to obtain a slurry.

[0053] 3) The slurry obtained above was dried in an oven at 70°C for 24 hours. The dried slurry was then ground in an agate mortar for 30 minutes to obtain a mixed powder with a particle size of about 14 μm.

[0054] 4) The mixed powder obtained above was sintered in air at 1500°C for 2 hours, and the sintered mixed powder was then ground in an agate mortar for 40 minutes. The particle size of the ground powder was about 58 μm, which is the material compared with the HfSiO4 bonding layer material for EBC with a coating microstructure that is resistant to TGO corrosion of the present invention.

[0055] Example 1: (The only difference from Comparative Example 1 is that SiO2 powder is replaced with silica sol)

[0056] This embodiment provides an EBC HfSiO4 adhesive layer material with a coating microstructure that is resistant to TGO corrosion, and its preparation method is as follows:

[0057] 1) Using HfO2 powder with a particle size of 6μm and a purity of 99.99wt.% and silica sol with a particle size of 8μm and a purity of 25wt.% (using water as a solvent) as raw materials, weigh the corresponding mass of the above HfO2 powder and silica sol according to the Hf:Si molar ratio of 1:1, and set them aside.

[0058] 2) After mixing the weighed HfO2 powder and silica sol, a mixture is obtained; an equal mass of anhydrous ethanol is added to the mixture as a ball milling aid, and the mixture is ball milled at a speed of 40 Hz for 20 h to obtain a slurry.

[0059] 3) The slurry obtained above was dried in an oven at 70°C for 24 hours. The dried slurry was then ground in an agate mortar for 30 minutes to obtain a mixed powder with a particle size of about 14 μm.

[0060] 4) The mixed powder obtained above is sintered in air at 1500°C for 2 hours, and the sintered body is ground in an agate mortar for 40 minutes. The particle size of the ground powder is 58 μm, thus obtaining the TGO corrosion resistant HfSiO4 bonding layer material for EBC with a coating microstructure of the present invention.

[0061] Example 2:

[0062] The only difference between this embodiment and Embodiment 1 is that the Hf:Si molar ratio in step 1) is replaced with 1:0.8, while the rest remain the same.

[0063] Example 3:

[0064] The only difference between this embodiment and Embodiment 1 is that the Hf:Si molar ratio in step 1) is replaced with 1:1.8, while the rest remain the same.

[0065] Example 4:

[0066] The only difference between this embodiment and Embodiment 1 is that the sintering temperature in step 3) is replaced with 1300℃, while the rest remain the same.

[0067] Example 5:

[0068] The only difference between this embodiment and Embodiment 1 is that the sintering temperature in step 3) is replaced with 1450℃, while the rest remain the same.

[0069] Example 6:

[0070] The only difference between this embodiment and Embodiment 1 is that the sintering temperature in step 3) is replaced with 1600℃, while the rest remain the same.

[0071] 1. TEM tests were performed on Example 1 and Comparative Example 1, and the results are as follows: Figure 5 and Figure 8 As shown, where Figure 5 The TEM images obtained for the uncoated powder prepared in Comparative Example 1 are shown in Figure (a), which is a microscopic schematic diagram of the uncoated powder, Figure (b) is the Hf elemental distribution map, Figure (c) is the Si elemental distribution map, and Figure (d) is the O elemental distribution map. Figure 8 The images are TEM images of the coated powder. Figure (a) is a microscopic schematic diagram of the coated powder, Figure (b) is the Hf element distribution map, Figure (c) is the Si element distribution map, Figure (d) is the O element distribution map, Figure (e) is a magnified view of Figure (a), Figure (f) is a magnified view of Figure (e), Figure (j) is the lattice fringe spacing of HfSiO4 and HfO2, and Figure (k) is the diffraction spot of HfSiO4. Figure 5 The results show that HfSiO4 in Comparative Example 1 has a plate-like structure and does not have a coating structure. Figure 8 The results in (f) show that HfO2 can be clearly observed to be embedded inside HfSiO4 in Example 1, thus forming a coated structure.

[0072] Furthermore, to verify that the synthesized powder has a coating structure, SiO2 corrosion experiments were conducted on both Example 1 and Comparative Example 1. The synthesized powder and high-purity SiO2 were ground and mixed in a mortar and pestle at a molar ratio of synthesized powder:SiO2 = 1:2. The mixture was then placed in a BN crucible for corrosion, and XRD tests were performed before and after corrosion. The results are as follows: Figure 4 , Figure 6 , Figure 7 As shown, where Figure 4 The XRD pattern of the synthesized uncoated HfSiO4 is shown. Figure 6 The images show the XRD patterns of uncoated powder before and after SiO2 etching. Figure 7 The XRD patterns of the coated powder before and after SiO2 etching are shown. Figure 6 and Figure 7 The comparison showed that no residual HfO2 was found in Comparative Example 1 after SiO2 corrosion, while residual HfO2 was still found in Example 1 after SiO2 corrosion. This indicates that the synthesized powder has a coating structure, and this coating structure is resistant to TGO corrosion. During the corrosion process, the coating structure will delay the mass transfer process of TGO, thereby delaying the shedding and fragmentation process of the entire EBC system and greatly improving the service life of EBC.

[0073] 2. Verify the effect of different molar ratios (Hf:Si) on the product;

[0074] To verify the effect of different molar ratios (Hf:Si) on the product, based on Example 1, only the molar ratio of Hf:Si was changed, and HfSiO4 was synthesized with Hf:Si = 1:0.8 to 1.6. XRD tests were performed on the coated HfSiO4, and the test results are as follows: Figure 4 As shown, from Figure 4 As can be seen, with the decrease of Hf:Si, residual SiO2 will appear when the ratio is greater than 1.6. Therefore, the molar ratio of Hf:Si must be controlled within 1.6 to ensure complete reaction and achieve the goal of no residual SiO2, thereby improving the purity and preparation efficiency of HfSiO4 and reducing preparation costs. When Hf:Si < 0.8, a large amount of residual HfO2 will exacerbate the corrosion of the binder material by oxygen; when Hf:Si > 1.6, residual SiO2 will accelerate the formation of thermally grown oxides in the binder material, thus exacerbating the detachment of the entire EBC.

[0075] 3. Verify the effect of different sintering temperatures on the product.

[0076] To verify the effect of different sintering temperatures on the product, based on Example 1, only the sintering temperature was changed, and HfSiO4 was synthesized in the temperature range of 1450-1600℃. The synthesized HfSiO4 was then subjected to XRD analysis, and the results are as follows: Figure 5 As shown, where Figure 5 XRD patterns showing the effect of different sintering temperatures on the products, from Figure 5 It can be seen that when sintering is carried out at a temperature below 1450℃, residual SiO2 will remain in the product. This is because insufficient activation energy is provided in the solid-state reaction to support the reaction, resulting in incomplete reaction between HfO2 and SiO2, and low purity of the generated HfSiO4. This phenomenon indicates that the reaction needs to be above 1450℃ to be complete. However, excessively high temperatures (above 1600℃) will increase energy consumption, production costs, and equipment wear, as well as accelerate crystal growth, leading to structural instability and affecting the physical and chemical stability of the material. Therefore, the preferred temperature range for this invention is 1450-1600℃.

[0077] To verify the feasibility of using the powder material synthesized in this invention as a bonding layer for SiC / SiC composite materials, 20g of the environmental barrier coating materials prepared in Examples 1-6 and Comparative Example 1 were placed in a graphite mold and sintered in a vacuum hot pressing furnace at 1500℃ / 35MPa for 2h to prepare the block ceramics corresponding to Examples 1-6 and Comparative Example 1.

[0078] The thermal expansion coefficient α (25-1600℃), the mass change rate Δm1 after 100h of dry air treatment at 1500℃, and the mass change rate Δm2 after 100h of water-oxygen corrosion at 1300℃ were tested for the bulk ceramics corresponding to Examples 1-6 and Comparative Example 1. The structures are shown in Table 1.

[0079] Table 1

[0080]

[0081] As shown in Table 1, the environmental barrier coating adhesive materials prepared in Examples 1, 2, 3, 5, and 6 showed significant improvements compared to the uncoated HfSiO4 material prepared in Comparative Example 1 after 100 hours of dry air treatment at 1500℃ and 100 hours of water-oxygen corrosion at 1300℃. Furthermore, the generated HfSiO4 had a suitable CTE value (matching the SiC / SiC composite material). In the EBC, water vapor and oxygen can penetrate through the top and intermediate coatings and react with the SiC matrix to form a TGO layer. The coated HfSiO4 structure can effectively delay the mass transfer process of TGO, thereby delaying the fragmentation and detachment of the entire EBC system.

[0082] As can be seen from the test results in Table 1, compared with Comparative Example 1, the thermal expansion coefficients of the adhesive layer materials in Examples 1, 2, 5, and 6 are still well matched with the SiC / SiC composite material; the mass change after 100 hours of dry air treatment at 1500℃ is minimal, almost zero, indicating that Example 1 has excellent resistance to drying oxidation; the mass change rate after 100 hours of water-oxygen corrosion at 1300℃ is lower than that of the uncoated HfSiO4, indicating that the resistance to water-oxygen corrosion of the coated HfSiO4 has been greatly improved. However, the resistance to water-oxygen corrosion of Example 3 is slightly worse than that of Examples 1, 2, 5, and 6. This is because the Hf:Si ratio is too small, resulting in residual SiO2 in the reaction products. The residual SiO2 will react with water vapor and oxygen to form TGO, which will aggravate the corrosion of the adhesive layer material. However, the overall resistance to water-oxygen corrosion and resistance to air drying are significantly improved compared with the comparative example, indicating that the coated structure has a significant effect. In Example 4, no HfSiO4 was generated during the sintering process at 1300℃. This is because the sintering temperature was too low and did not provide sufficient activation energy to support the reaction. The reaction products consisted of unreacted SiO2 and HfO2, both of which have excellent resistance to high-temperature oxidation. Their mass did not change much under dry air treatment at 1500℃. However, under water-oxygen corrosion at 1300℃, the residual SiO2 in the binder material would react with water vapor and oxygen to form TGO, which would aggravate the corrosion of the binder material and thus exacerbate the weight loss of the bulk ceramic. Therefore, the weight loss due to water-oxygen corrosion was the greatest in Example 4.

[0083] As an application of HfSiO4 as a bonding layer material, the HfSiO4 bonding layer formed on the surface of SiC / SiC composite material has a microstructure as follows: Figure 1 As shown. Methods for forming the bonding layer include atmospheric plasma spraying, physical vapor deposition, and slurry coating, all of which are conventional techniques in this field and will not be described in detail here.

[0084] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for preparing an EBC (Extracorporeal Biofilm Charge) adhesive layer material with a coating microstructure resistant to TGO (Total Volatile Organic Compound) corrosion, characterized in that, Includes the following steps: S1. HfO2 powder and silica sol are mixed at an Hf:Si molar ratio of 1:0.8~1.6, and then wet ball milled to obtain a slurry; the slurry is dried and then ground to obtain a mixed powder. S2. The mixed powder is sintered at 1450~1600 ℃ for 1~5h and then ground into powder to obtain HfSiO4 bonding layer material for EBC with a coating microstructure that is resistant to TGO corrosion. The encapsulated microstructure is a microstructure in which HfSiO4 encapsulates HfO2.

2. The preparation method according to claim 1, characterized in that, The HfO2 powder and silica sol are mixed at an Hf:Si molar ratio of 1:1 to 1.

2.

3. The preparation method according to claim 1, characterized in that, The purity of the HfO2 powder is ≥99.99 wt.%; and / or the particle size of the HfO2 powder is 3~6 μm.

4. The preparation method according to claim 1, characterized in that, The purity of the silica sol is 25 wt.%; and / or the particle size of SiO2 in the silica sol is 8~12 μm.

5. The preparation method according to claim 1, characterized in that, The ball milling aid used in the wet ball milling process is anhydrous ethanol, the ball milling rate is 20~60 Hz, and the ball milling time is 12~24 h.

6. The preparation method according to claim 1, characterized in that, The drying temperature of the slurry is 60~80 ℃, and the drying time is 12~24 h.

7. The preparation method according to claim 1, characterized in that, In step S1, the grinding conditions are an agate mortar and pestle, and the grinding time is 20-40 min; in step S2, the grinding conditions are an agate mortar and pestle, and the grinding time is 30-50 min.

8. The preparation method according to claim 1, characterized in that, In step S1, the particle size after grinding is 10~15 μm; in step S2, the particle size of the powder after grinding is 40~70 μm.

9. An HfSiO4 adhesive layer material, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. The application of the HfSiO4 bonding layer material according to claim 9 in the preparation of HfSiO4 bonding layers.

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