A self-healing, antioxidant, biomimetic glass film and its preparation method

Abstract

This invention belongs to the field of high-temperature antioxidant coatings, specifically relating to a method for preparing a self-healing antioxidant biomimetic glass film. The invention involves coating a ceramic substrate with a layer of multiphase glass powder composed of silica sol, borosilicate glass powder, nano-HfO2 powder, and nano-Ta2O5 powder. After "drainage drying—heat treatment—wide-temperature-range heat treatment," a biomimetic glass film is formed. This method effectively avoids the self-damage caused by oxidation of silicon-based ceramics, as well as the poor film formation effect and weak self-healing repair ability due to severe high-temperature oxidation. Simultaneously, it ensures the uniform dispersion of high-temperature refractory oxides in the glass film, guaranteeing the high-temperature stability of the glass film and effectively improving the antioxidant performance of silicon-based ceramics. The preparation method disclosed in this invention is simple to operate, cost-effective, and the prepared biomimetic glass film has good adhesion to the ceramic substrate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-temperature oxidation-resistant coatings, and particularly relates to a self-healing oxidation-resistant biomimetic glass film and a preparation method thereof. BACKGROUND

[0002] Silicon-based ceramics such as SiC and MoSi2, and super-high-temperature borides such as HfB2, ZrB2 and TaB2 have excellent properties such as high melting point, chemical stability and high-temperature resistance, and a low-oxygen-permeable boron / silicon-based glass film can be generated on the surface after oxidation, so they are widely used as oxidation-resistant ceramic coating materials for carbon structural materials. However, the oxidation rate of boron / silicon-based ceramic coatings is low in a low-temperature environment, and the generated amorphous glass film is not uniform and complete, so it is difficult to effectively repair defects such as pores and cracks in the coating; the boron / silicon-based ceramic coating is severely oxidized at a high temperature of 1500°C or above, the coating components are rapidly oxidized and expanded, and a large amount of volatile gas is generated, so the number of defects such as pores and cracks in the coating increases greatly, the stability of the glass film is poor, and the repair ability is weakened. Based on the above problems, in order to improve the oxidation resistance of ceramic materials, researchers design the structure and oxidation method of the ceramic coating, such as designing a porous pre-coating and pre-oxidizing the ceramic coating to form a film for regulation, but these methods still have the disadvantages of high porosity of the ceramic coating material, many oxidation active points, and poor self-generating film effect.

[0003] Document 1 "SiC-Si coating with micro-pores to protect carbon / carbon composites against oxidation. Xiaofei Zhu, Yulei Zhang, Yangyang Su, Yanqin Fu, Pei Zhang. Journal of the European Ceramic Society, 2021, 41(1):114-120." discloses a method for preparing a double-layer SiC-Si ceramic coating with micro-pores by a two-step method. The method first prepares a SiC-Si inner coating by embedding, and then prepares a SiC-Si outer coating containing a micro-porous structure by a slurry method and a heat treatment process. The method is easy to operate and simple in process control, oxygen can diffuse into the porous ceramic through the micro-pores, and more SiO2 glass is generated to protect the substrate from oxidation. However, the coating prepared by this method has high porosity, low density and many oxidation active points, and the generated silicon-based glass may not heal the pores in time at a high temperature of 1500°C or above, so oxygen will further penetrate into the interior through the pores, and the large amount of volatile gas generated by the oxidation of the coating can damage the integrity of the glass film, thereby causing more and more defects in the ceramic coating and weakening the oxygen-blocking ability.

[0004] Document 2“Effect of flm-forming regulation of the self-formed compound layer on the oxidation inhibition capacity of HfB2-SiC coating. Binbin Wu, Peipei Wang, Xuanru Ren, Mingcheng Zhang, Yuexing Chen, Tengfei Kan, Dalin Shi, Xueqin Kang, Peizhong Feng. Ceramics International, 2022, 48(15): 22039-22052.” discloses a method of preparing an oxidation-resistant glass film by pre-oxidation treatment on the surface of a ceramic coating. The method regulates the film formation of HfB2-SiC ceramic coating at different pre-oxidation temperatures and different pre-oxidation times, and it is found that pre-oxidizing the ceramic coating at a suitable temperature for a suitable time can avoid its severe oxidation damage at 1700℃, and improve the dynamic stability and oxygen resistance of the coating. However, the pre-oxidation self-generated film is still formed on the basis of damaging the coating itself, and problems such as coating loss, reaction leaving oxidation holes, and uneven distribution of phases in the glass film occur during the oxidation of the self-generated film. In addition, during the initial pre-oxidation stage, oxygen can still diffuse through the pores in the coating to the interior of the coating and the substrate.

[0005] Avoiding the damage of the self-generated film of the ceramic material and improving the quality of the film are the key to improving the high-temperature oxidation resistance of boron / silicon-based ceramic materials. SUMMARY

[0006] The present application provides a self-healing oxidation-resistant biomimetic glass film and a preparation method. The method of "slurry brushing-drainage-heat treatment" is used to prepare a complex biomimetic glass film, which has good bonding effect between the prepared glass film and the ceramic substrate, thereby solving the problems of severe oxidation of ceramic materials in high-temperature environments, large increase in defects such as pores, poor self-generated film effect, and weakened oxidation-resistant self-repairing ability, and providing a simple and effective method for improving the oxidation resistance of boron / silicon-based ceramic materials.

[0007] The technical solution of the present application is as follows:

[0008] A self-healing oxidation-resistant biomimetic glass film and a preparation method, the steps are as follows:

[0009] S1. After polishing and polishing the ZrB2-SiC ceramic substrate, ultrasonic cleaning is performed, and the substrate is placed in an oven for drying, and is ready for use;

[0010] S2. The borosilicate glass powder, HfO2 powder, Ta2O5 powder are placed in a ball mill in proportion, mixed and stirred uniformly for standby;

[0011] S3. The mixed powder is heat treated to form a molten composite glass, which is taken out and cooled to room temperature;

[0012] S4. The treated composite glass is placed in a mortar and broken, and after breaking, it is placed in a ball mill for ball milling and refinement;

[0013] S5. The ground composite glass powder is placed in a silicon sol, and magnetically mixed and stirred to prepare a slurry for standby;

[0014] S6. The slurry obtained in S5 is evenly brushed on the surface of the ceramic substrate obtained in S1, and is placed in an oven for drainage drying for standby, to obtain a sample;

[0015] S7. The dried sample is placed in a resistance furnace for heat treatment for standby;

[0016] S8. The sample obtained in S7 is placed in an oxidation furnace for film formation with the furnace temperature rising at a uniform speed, from room temperature to 1600℃, to complete the preparation of the biomimetic glass film.

[0017] As an improvement, the mass ratio of the borosilicate glass powder, HfO2 powder, Ta2O5 powder in S2 step is: 7-15:8-18:0-2.

[0018] As an improvement, the mixing and stirring time in S2 step is 2.5-3.5 hours.

[0019] As an improvement, the heat treatment temperature in S3 step is 1300℃, and the heat treatment time is 20-40min.

[0020] As an improvement, the ball milling and refinement in S4 step uses a high-energy ball mill, and the ball milling and refinement time is 4-5h.

[0021] As an improvement, the mass ratio of silicon sol to composite glass powder in S5 step is 10:23.

[0022] As an improvement, the temperature of the oven in S6 step is 400℃, and the drying time is 2-3h.

[0023] As an improvement, the temperature of the resistance furnace heat treatment in S7 step is 1100-1300℃, and the heat treatment time is 2h.

[0024] As an improvement, the temperature rising rate of the uniform temperature rising in S8 step is 5℃ / min.

[0025] The research and development inspiration of the present application comes from Pinus massoniana. When Pinus massoniana is injured, the wound will quickly flow out of the resin to prevent the invasion of bacteria, and the terpenoids in the resin will undergo specific variation and participate in the stress response of the plant, so as to promote the wound to heal as soon as possible and realize rapid self-repair. The resin acid and terpenes are mainly composed of the resin acid and terpenes, the terpenes are volatile substances, the resin acid is non-volatile substance, the high-temperature volatile borosilicate glass can be used as 'terpenes', and the difficult-to-melt HfO2 and Ta2O5 can be used as'resin acid'. The antioxidant biomimetic glass film simulating the wound self-healing repair mechanism of Pinus massoniana is prepared. When the cracking (wound) caused by alternating thermal stress of high and low temperature occurs, the flowing glass film (resin) quickly fills the crack (wound), promotes the rapid healing of the crack (wound), and prevents the invasion of oxygen (bacteria) into the coating and the substrate.

[0026] The technical advantage of the present application is that:

[0027] 1. A layer of complex glass powder composed of silica sol and borosilicate glass powder, nano HfO2 powder and nano Ta2O5 powder is brushed on the surface of the ceramic substrate, and after 'drainage drying-heat treatment-wide temperature range heat treatment', a biomimetic glass film is formed. The method can effectively avoid the self-damage of the silicon-based ceramic oxidation, and the poor self-film effect and weak self-healing repair ability caused by high-temperature severe oxidation; at the same time, the high-temperature refractory oxide is uniformly dispersed in the glass film, which ensures the high-temperature stability of the glass film and effectively improves the oxidation resistance of the silicon-based ceramic.

[0028] 2. The preparation method disclosed by the present application is simple in operation, saves cost, and the prepared biomimetic glass film has good combination with the ceramic substrate. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is the preparation process flow chart of the present application.

[0030] Figure 2 is the macroscopic photo of the ceramic substrate surface after brushing the complex glass powder and drying in the embodiment of the present application.

[0031] Figure 3 is the surface backscattered electron microscope photo of the biomimetic glass film prepared in the embodiment of the present application: Figure 3 (a) is HT0; Figure 3 (b) is HT5; Figure 3 (c) is HT10; Figure 3 (d) is HT15.

[0032] Figure 4 is the weight change curve of the four samples prepared in the embodiment of the present application after oxidation at 1700 DEG C. DETAILED DESCRIPTION

[0033] The application will be described in detail and specifically below through specific examples, so that the application can be better understood. However, the following examples do not limit the protection scope of the application. Example 1

[0034] This embodiment discloses a self-healing antioxidant biomimetic glass film and a preparation method, and the steps are as follows:

[0035] S1. After polishing and polishing the ZrB2-SiC ceramic matrix, ultrasonic cleaning is performed, and the ceramic matrix is placed in an oven for drying and standby.

[0036] S2. The borosilicate glass powder, HfO2 powder and Ta2O5 powder are placed in a ball mill in a mass ratio of 10:13:0, ball-milled for 3 hours, and stirred uniformly for standby.

[0037] S3. The mixed powder is heat treated at 1300℃ for 30 minutes to form a molten composite glass, which is taken out and cooled to room temperature.

[0038] S4. The treated composite glass is placed in a mortar and crushed with a pestle. After crushing, it is placed in a high-energy ball mill and ball-milled for 5 hours for standby.

[0039] S5. The ground composite glass powder is placed in a silicon sol, and the mass ratio of the silicon sol to the composite glass powder is 10:23. The mixture is stirred magnetically for 2 hours to prepare a slurry for standby.

[0040] S6. The slurry obtained in S5 is evenly brushed on the surface of the ceramic matrix obtained in S1, and is placed in an oven at a temperature of 400℃ for 2 hours for drainage drying for standby. The sample is denoted as HT0, and the macroscopic morphology after brushing and drying is shown in Figure 2 .

[0041] S7. The dried HT0 sample is placed in a 1300℃ electric resistance furnace for heat treatment for 2 hours for standby.

[0042] S8. The sample obtained in S7 is placed in an oxidation furnace and heated with the furnace at a rate of 5℃ / min from room temperature to 1600℃ to form a film, and the biomimetic glass film is prepared for standby. The surface micro-morphology of the prepared biomimetic glass film is shown in Figure 3 (a).

[0043] S9. The sample coated with the biomimetic glass film in S8 is weighed and recorded on an analytical balance, and then is placed in an oxidation furnace heated to 1700℃ for oxidation test. The sample is taken out every 10 minutes for weighing, and the cumulative weight change is shown in Figure 4 .

[0044] After the above steps, the HT0 sample is prepared and oxidized at 1700℃ for 100 minutes, and the weight gain is 1.138×10-2 g / cm 2 . Example 2

[0045] The embodiment discloses a self-healing antioxidant biomimetic glass film and a preparation method, and steps are as follows:

[0046] S1. After polishing and polishing the ZrB2-SiC ceramic matrix, ultrasonic cleaning is performed, and the ceramic matrix is placed in an oven for drying, and is ready for use.

[0047] S2. Borosilicate glass powder, HfO2 powder and Ta2O5 powder are placed in a ball mill in a mass ratio of 15:18:1, ball-milled for 3 hours, and stirred uniformly for standby.

[0048] S3. The mixed powder is heat treated at 1300 DEG C for 30 minutes to form a molten composite glass, and the composite glass is taken out and cooled to room temperature.

[0049] S4. The treated composite glass is placed in a mortar and crushed with a pestle, and after crushing, it is placed in a high-energy ball mill for 5 hours for standby.

[0050] S5. The ground composite glass powder is placed in a silicon sol, and the mass ratio of the silicon sol to the composite glass powder is 10:23, and the mixture is stirred for 2 hours by magnetic force to prepare a slurry for standby.

[0051] S6. The slurry obtained in S5 is uniformly brushed on the surface of the ceramic matrix obtained in S1, and is placed in an oven at a temperature of 400 DEG C for 2 hours for drainage drying for standby. The macroscopic morphology of the sample after brushing and drying is shown in Figure 2 .

[0052] S7. The dried HT5 sample is placed in a 1300 DEG C electric resistance furnace for heat treatment for 2 hours for standby.

[0053] S8. The sample obtained in S7 is placed in an oxidation furnace and heated with the furnace to form a film, and the heating rate is 5 DEG C / min, and the temperature is increased from room temperature to 1600 DEG C, and the biomimetic glass film is prepared for standby. The surface micro-morphology of the prepared biomimetic glass film is shown in Figure 3 (b).

[0054] S9. The sample coated with the biomimetic glass film in S8 is weighed on an analytical balance and recorded, and then is placed in an oxidation furnace heated to 1700 DEG C for oxidation test, and the sample is taken out every 10 minutes for weighing, and the cumulative weight change is shown in Figure 4 .

[0055] After the above steps, the HT5 sample is prepared and is oxidized at 1700 DEG C for 100 minutes, and the weight gain is 1.023x10 -2 g / cm 2 . Example 3

[0056] The embodiment discloses a self-healing antioxidant biomimetic glass film and a preparation method, and steps are as follows:

[0057] S1. After polishing and polishing the ZrB2-SiC ceramic matrix, ultrasonic cleaning is performed, and the ceramic matrix is placed in an oven for drying, and is ready for use.

[0058] S2. Borosilicate glass powder, HfO2 powder and Ta2O5 powder are placed in a ball mill in a mass ratio of 7:8:1, ball milling is performed for 3 hours, and stirring is uniformly performed, and the mixture is ready for use.

[0059] S3. The mixed powder is heat treated at 1300 DEG C for 30 minutes, so that the powder is formed into a molten composite glass, and the composite glass is taken out and cooled to room temperature.

[0060] S4. The treated composite glass is placed in a mortar, and is broken by a pestle, and after the breaking is completed, the composite glass is placed in a high-energy ball mill and ball milled for 5 hours, and is ready for use.

[0061] S5. The milled composite glass powder is placed in a silicon sol, the mass ratio of the silicon sol to the composite glass powder is 10:23, and magnetic mixing and stirring are performed for 2 hours, so that a slurry is prepared and is ready for use.

[0062] S6. The slurry obtained in S5 is uniformly brushed on the ceramic matrix surface obtained in S1, and is placed in an oven at a temperature of 400 DEG C for 2 hours, and is subjected to drainage drying and is ready for use. The sample is recorded as HT10, and the macroscopic morphology of the sample after brushing and drying is as shown in Figure 2 .

[0063] S7. The dried HT10 sample is placed in a 1300 DEG C electric resistance furnace and is heat treated for 2 hours and is ready for use.

[0064] S8. The sample obtained in S7 is placed in an oxidation furnace and is formed into a film along with the furnace, the heating rate is 5 DEG C / min, the temperature is increased from room temperature to 1600 DEG C, the biomimetic glass film is prepared, and is ready for use. The surface micro-morphology of the prepared biomimetic glass film is as shown in Figure 3 (c). With the increase of the content of Ta2O5 in the biomimetic glass film, the uniform dispersibility of the refractory oxide in the glass film is improved.

[0065] S9. The sample coated with the biomimetic glass film in S8 is weighed on an analytical balance and is recorded, and then is placed in an oxidation furnace heated to 1700 DEG C for oxidation test, the sample is taken out and weighed every 10 minutes, and the cumulative weight change is as shown in Figure 4 .

[0066] After the above steps, the HT10 sample is prepared and is oxidized at 1700 DEG C for 100 minutes, and the weight gain is only 0.721x10 -2 g / cm 2, compared with HT0, HT5, HT15 samples, respectively decreased by 36.6%, 29.5% and 27.0%. HT10 sample has the smallest weight change at 1700℃ and the best oxidation resistance. The appropriate addition of Ta2O5 and its interaction with HfO2 and SiO2 make the HT10 sample glass film have the best self-healing repairability. Example 4

[0067] The embodiment discloses a self-healing oxidation-resistant biomimetic glass film and a preparation method, and the steps are as follows:

[0068] S1. After polishing and polishing the ZrB2-SiC ceramic matrix, ultrasonic cleaning is performed, and the ceramic matrix is placed in an oven for drying and standby.

[0069] S2. The borosilicate glass powder, HfO2 powder and Ta2O5 powder are placed in a ball mill in a mass ratio of 10:11:2, ball-milled for 3 hours, and stirred uniformly for standby.

[0070] S3. The mixed powder is heat-treated at 1300℃ for 30 minutes to form a molten complex glass, and the complex glass is taken out and cooled to room temperature.

[0071] S4. The treated complex glass is placed in a mortar and crushed with a pestle, and after crushing, it is placed in a high-energy ball mill for 5 hours for standby.

[0072] S5. The ground complex glass powder is placed in a silicon sol, and the mass ratio of the silicon sol to the complex glass powder is 10:23, and the mixture is stirred for 2 hours to prepare a slurry for standby.

[0073] S6. The slurry obtained in S5 is uniformly brushed on the surface of the ceramic matrix obtained in S1, and is placed in an oven at a temperature of 400℃ for 2 hours for drainage drying for standby. The sample is denoted as HT15, and the macroscopic morphology of the sample after brushing and drying is shown in Figure 2 .

[0074] S7. The dried HT15 sample is placed in a 1300℃ electric resistance furnace for heat treatment for 2 hours for standby.

[0075] S8. The sample obtained in S7 is placed in an oxidation furnace for film formation with the furnace, and the heating rate is 5℃ / min, and the temperature is increased from room temperature to 1600℃, and the biomimetic glass film is prepared for standby. The surface micro-morphology of the prepared biomimetic glass film is shown in Figure 3 (d).

[0076] S9. The sample coated with the biomimetic glass film in S8 is weighed and recorded on an analytical balance, and then is placed in an oxidation furnace heated to 1700℃ for oxidation test, and the sample is taken out and weighed every 10 minutes, and the cumulative weight change is calculated as shown in Figure 4 .

[0077] After the above steps, the HT15 sample is prepared to be oxidized at 1700 DEG C for 100 minutes, and the weight gain is 0.990*10 -2 g / cm 2 The strong complexation of excess Ta2O5 in the glass film leads to the weakened self-healing repair ability of the glass film, and the oxidation resistance is reduced compared with the HT10 sample.

[0078] The water content in the silica sol described in all the above examples is 70%; the purity of the HfO2 powder and the Ta2O5 powder is > 99.95%, and the particle size is 1000 mesh.

[0079] The specific embodiments of the present application are described in detail above, but it is only as an example, and the present application is not equivalent to the specific embodiments described above. Any equivalent modification and substitution of the present application for those skilled in the art are also within the scope of the present application. Therefore, any equivalent transformation and modification made without departing from the spirit and scope of the present application should be covered within the scope of the present application.

Claims

1. A method for preparing a self-healing antioxidant biomimetic glass film, characterized in that, The steps are as follows: S1. After polishing and polishing the ZrB2-SiC ceramic matrix, ultrasonic cleaning, drying in an oven, standby; S2. Borosilicate glass powder, HfO2 powder, Ta2O5 powder are placed in a ball mill in proportion, mixed and stirred uniformly, standby, the mass ratio of the borosilicate glass powder, HfO2 powder, Ta2O5 powder is: 7-15:8-18:0-2; S3. Heat treatment is performed on the mixed powder to form a molten complex glass, which is taken out and cooled to room temperature; S4. The treated complex glass is placed in a mortar and broken, and after breaking, it is placed in a ball mill for ball milling; S5. Put the ground complex glass powder into the silica sol, and mix and stir with magnetic force to prepare a slurry for standby; S6. The slurry obtained in S5 is evenly brushed on the surface of the ceramic matrix obtained in S1, and is placed in an oven for drainage drying standby, to obtain a sample; S7. The dried sample is placed in a resistance furnace for heat treatment standby; S8. The sample obtained in S7 is placed in an oxidation furnace to form a film with the furnace, and the temperature is uniformly increased from room temperature to 1600℃, to complete the preparation of the biomimetic glass film.

2. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The mixing and stirring time in S2 step is 2.5-3.5 hours.

3. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The heat treatment temperature in S3 step is 1300℃, and the heat treatment time is 20-40min.

4. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, In S4 step, high-energy ball milling is used for ball milling, and the ball milling time is 4-5h.

5. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The mass ratio of silica sol to complex glass powder in S5 step is 10:

23.

6. The method of claim 1, wherein the self-healing antioxidant biomimetic glass film is prepared by the steps of: The temperature of the oven in S6 step is 400℃, and the drying time is 2-3h.

7. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The temperature of the resistance furnace heat treatment in S7 step is 1100-1300℃, and the heat treatment time is 2h.

8. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The temperature increasing rate of the uniform temperature increasing in S8 step is 5℃ / min.

9. The method for preparing a self-healing, antioxidant, biomimetic glass film according to claim 1, characterized in that, The water content of the silica sol in S5 step is 70%.

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