A method for in-situ rapid microcrystallization of MoSi2-ZrSi2-ZrB2 composite powder for anti-oxidation coating of carbon-based composite materials.

Abstract

This invention discloses an in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used in anti-oxidation coatings on carbon-based composite materials. The method involves using powder prepared through combustion synthesis, which is then pulverized and placed into a high-temperature quartz glass test tube fitted with a graphite sleeve. The test tube is then placed inside an induction heating furnace coil for in-situ rapid microcrystallization. Compared to traditional direct heating methods, this method solves the problem of uneven microcrystallization on the powder surface, significantly shortens the microcrystallization cycle, and reduces self-generated defects in the powder caused by in-situ oxidation. After treatment, the microcrystals formed on the powder surface not only act as a particle binder but also as an anti-oxidation layer, enhancing the density of the coating structure and directly providing a physical barrier against oxygen penetration. This method has the advantage of improving the oxygen barrier structure of the anti-oxidation coating, providing a new and effective approach for anti-oxidation treatment of carbon-based composite material surfaces.

Description

Technical Field

[0001] This invention relates to the field of carbon-based composite materials, specifically to an in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used for anti-oxidation coating on the surface of carbon-based composite materials. Background Technology

[0002] Carbon-based composites are promising high-temperature structural components for aerospace applications due to their low density, high specific strength, low coefficient of thermal expansion, and excellent creep resistance. In particular, carbon-based composites exhibit excellent mechanical properties at high temperatures in non-oxidizing atmospheres. However, their significant oxidation susceptibility severely limits their practical application at high temperatures, and applying anti-oxidation coatings to their surfaces is considered one of the effective methods to improve oxidation resistance.

[0003] In the field of antioxidant coatings, ZrB2-based coatings have attracted much attention due to their unique physical and chemical properties, such as moderate density, high melting point, chemical inertness, and high electrical conductivity, and are widely used to provide thermal protection for carbon-based composites under extreme temperatures. However, B2O3, a pure ZrB2 oxidation product, has very low viscosity and significant evaporation at temperatures above 1373 K, making it difficult for ZrB2 alone to provide excellent antioxidant performance. Given the excellent self-sealing ability and low oxygen permeability of the oxidized SiO2 glass, silicon-based ceramic components (such as SiC and ZrSi2) are often used as silicon sources for film formation to further enhance the antioxidant properties of ultra-high temperature ceramic borides. However, the formation process of molten SiO2 glass can only be achieved under high temperature conditions. In sub-high temperature environments, the formation rate of the oxide film in the coating is significantly delayed, its protective effect is weakened, and it is difficult to effectively prevent the penetration of oxygen molecules. Therefore, improving the film-forming performance and oxygen permeation resistance of the coating under sub-high temperature conditions is particularly important.

[0004] Zhu Lu et al. (Zhu Lu. Preparation and High-Temperature Antioxidant Properties of Coatings Based on Recycling Waste Molybdenum Silicon Rods [D]. China University of Mining and Technology, 2022) prepared a complete and dense MoSi2-ZrSi2-SiC multiphase coating using a low-temperature hot-pressing rapid sintering process. Although the coating formed a high-viscosity and crack-free Zr-Si-O multiphase glass film after high-temperature oxidation, effectively hindering further oxygen diffusion, the protective performance of the coating was limited in the early stage of oxidation due to the certain lag in the formation of the self-generated glass film. Zhang Menglin et al. (Zhang Menglin. Preparation and High Oxygen Barrier Mechanism of Hafnium Boride Coating Modified by Transition Metal Silicides [D]. China University of Mining and Technology, 2022) introduced film-forming silicon source MSi2 (M = Ta, Zr, and W) through mechanical blending and utilized the rapid film-forming effect of silicide oxidation to accelerate the dispersion rate of oxide nanocrystals in borosilicate, thereby improving the coating's ability to inhibit oxygen permeation. However, TaSi2 and WSi2 have high oxidation activity in the low-temperature region (600-900℃), while the crystal transformation of ZrO2 leads to significant oxidation loss of the ZrSi2 system in the medium-temperature region (900-1300℃), resulting in poor oxygen barrier effect and thus weakening the anti-oxidation performance of the coating.

[0005] Therefore, in order to improve the application effect of composite coatings in complex environments with a wide temperature range and multiple scales, there is an urgent need for a high-quality powder preparation method that can enhance the protection capabilities at medium and low temperatures and improve the oxygen barrier effect of the structure after coating. Summary of the Invention

[0006] The present invention aims to provide an in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder for anti-oxidation coating on carbon-based composite materials, thereby overcoming the shortcomings of the existing technology.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for in-situ rapid microcrystallization of MoSi2-ZrSi2-ZrB2 composite powder for anti-oxidation coating of carbon-based composite materials specifically includes the following steps:

[0009] 1) Powder preparation and loading: The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was crushed and loaded into a high-temperature quartz glass test tube, and then fitted with a graphite sleeve.

[0010] 2) Placement and start-up of the induction heating furnace: Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and perform in-situ rapid microcrystallization treatment;

[0011] 3) Perform in-situ rapid microcrystallization treatment: Start the in-situ rapid microcrystallization treatment and allow it to cool naturally after the treatment is completed;

[0012] 4) Cooling and product processing: After cooling to room temperature, the powder product in the test tube is separated and ground evenly to obtain MoSi2-ZrSi2-ZrB2 powder with in-situ rapid microcrystallization treatment.

[0013] As a preferred embodiment, the amount of material to be filled in step 1) is 5g to 20g.

[0014] As a preferred embodiment, the in-situ rapid microcrystallization treatment temperature in step 3) is 750–900°C.

[0015] As a preferred embodiment, the in-situ rapid microcrystallization treatment time in step 3) is 150–300 s.

[0016] The advantages of this invention compared to the prior art are:

[0017] 1. The in-situ rapid microcrystallization method for powders involved in this invention can create a dense, antioxidant barrier layer on the powder surface, exhibiting a significant oxygen barrier enhancement effect under medium and low temperature conditions, thereby improving service life at high temperatures. The unique structural design of this powder gives it a wide thermal protection temperature range advantage after coating, demonstrating enhanced protective effects across multiple temperature ranges.

[0018] 2. This invention achieves in-situ nucleation and non-destructive growth of microcrystalline powder structures through rapid microcrystallization treatment, and utilizes efficient energy transfer and uniform temperature distribution characteristics to realize the rapid synthesis of high-quality microcrystalline powders. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the present invention.

[0020] Figure 2 The X-ray diffraction phase analysis results are as follows: the MoSi2-ZrSi2-ZrB2 powder obtained by in-situ rapid microcrystallization treatment in Examples 1 to 4 of the present invention and the MoSi2-ZrSi2-ZrB2 powder obtained by Comparative Example 1 without in-situ rapid microcrystallization treatment.

[0021] Figure 3 The image shows the SEM morphology and EDS spectrum of the MoSi2-ZrSi2-ZrB2 powder obtained by in-situ rapid microcrystallization treatment in Example 1 of this invention.

[0022] Figure 4 The image shows the SEM morphology and EDS spectrum of the MoSi2-ZrSi2-ZrB2 powder obtained by in-situ rapid microcrystallization treatment in Example 2 of this invention.

[0023] Figure 5The image shows the SEM morphology and EDS spectrum of the MoSi2-ZrSi2-ZrB2 powder obtained by in-situ rapid microcrystallization treatment in Example 3 of this invention.

[0024] Figure 6 The image shows the SEM morphology and EDS spectrum of the MoSi2-ZrSi2-ZrB2 powder obtained by in-situ rapid microcrystallization treatment in Example 4 of this invention.

[0025] Figure 7 The image shows the SEM morphology and EDS spectrum of the MoSi2-ZrSi2-ZrB2 powder obtained in Comparative Example 1 of this invention without in-situ rapid microcrystallization treatment. Detailed Implementation

[0026] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0027] Example 1:

[0028] The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used for surface anti-oxidation coating of carbon-based composite materials involved in this embodiment is carried out according to the following steps:

[0029] (1) The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was pulverized and 5g of powder was placed in a high-temperature quartz glass test tube and fitted with a graphite sleeve.

[0030] (2) Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and carry out in-situ rapid microcrystallization treatment.

[0031] (3) Start the in-situ rapid microcrystallization treatment (microcrystallization treatment temperature: 750℃, microcrystallization treatment time: 150s), and allow it to cool naturally after the treatment is completed;

[0032] (4) After cooling to room temperature, separate the powder product in the test tube, grind it evenly, and obtain the in-situ rapid microcrystallization treated MoSi2-ZrSi2-ZrB2 powder.

[0033] The phase structure and microstructure of the powder obtained after in-situ rapid microcrystallization treatment are as follows: Figure 2 and Figure 3 As shown in Table 1, to further verify the quality of the powder after in-situ rapid microcrystallization treatment, the matrix loss rate of the powder obtained in Example 1 after coating and 1700℃ ultra-high temperature static oxidation is shown in Table 1.

[0034] Example 2:

[0035] The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used for surface anti-oxidation coating of carbon-based composite materials involved in this embodiment is carried out according to the following steps:

[0036] (1) The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was pulverized and 10g of the powder was put into a high-temperature quartz glass test tube and fitted with a graphite sleeve.

[0037] (2) Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and carry out in-situ rapid microcrystallization treatment.

[0038] (3) Start the in-situ rapid microcrystallization treatment (microcrystallization treatment temperature: 800℃, microcrystallization treatment time: 200s), and allow it to cool naturally after the treatment is completed;

[0039] (4) After cooling to room temperature, separate the powder product in the test tube, grind it evenly, and obtain the in-situ rapid microcrystallization treated MoSi2-ZrSi2-ZrB2 powder.

[0040] The phase structure and microstructure of the powder obtained after in-situ rapid microcrystallization treatment are as follows: Figure 2 and Figure 4 As shown in Table 1, to further verify the quality of the powder after in-situ rapid microcrystallization treatment, the matrix loss rate of the powder obtained in Example 2 after coating and 1700℃ ultra-high temperature static oxidation is shown in Table 1.

[0041] Example 3:

[0042] The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used for surface anti-oxidation coating of carbon-based composite materials involved in this embodiment is carried out according to the following steps:

[0043] (1) The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was pulverized and 15g of the powder was put into a high-temperature quartz glass test tube and fitted with a graphite sleeve.

[0044] (2) Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and carry out in-situ rapid microcrystallization treatment.

[0045] (3) Start the in-situ rapid microcrystallization treatment (microcrystallization treatment temperature: 850℃, microcrystallization treatment time: 250s), and allow it to cool naturally after the treatment is completed;

[0046] (4) After cooling to room temperature, separate the powder product in the test tube, grind it evenly, and obtain the in-situ rapid microcrystallization treated MoSi2-ZrSi2-ZrB2 powder.

[0047] The phase structure and microstructure of the powder obtained after in-situ rapid microcrystallization treatment are as follows: Figure 2 and Figure 5 As shown in Table 1, to further verify the quality of the powder after in-situ rapid microcrystallization treatment, the matrix loss rate of the powder obtained in Example 3 after coating and 1700℃ ultra-high temperature static oxidation is shown in Table 1.

[0048] Example 4:

[0049] The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder used for surface anti-oxidation coating of carbon-based composite materials involved in this embodiment is carried out according to the following steps:

[0050] (1) The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was pulverized and 20g of powder was put into a high-temperature quartz glass test tube and fitted with a graphite sleeve.

[0051] (2) Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and carry out in-situ rapid microcrystallization treatment.

[0052] (3) Start the in-situ rapid microcrystallization treatment (microcrystallization treatment temperature: 900℃, microcrystallization treatment time: 300s), and allow it to cool naturally after the treatment is completed;

[0053] (4) After cooling to room temperature, separate the powder product in the test tube, grind it evenly, and obtain the in-situ rapid microcrystallization treated MoSi2-ZrSi2-ZrB2 powder.

[0054] The phase structure and microstructure of the powder obtained after in-situ rapid microcrystallization treatment are as follows: Figure 2 and Figure 6 As shown in Table 1, to further verify the quality of the powder after in-situ rapid microcrystallization treatment, the matrix loss rate of the powder obtained in Example 4 after coating and 1700℃ ultra-high temperature static oxidation is shown in Table 1.

[0055] Comparative Example 1:

[0056] The MoSi2-ZrSi2-ZrB2 powder involved in this comparative example is the MoSi2-ZrSi2-ZrB2 powder that has not undergone in-situ rapid microcrystallization treatment, but is directly prepared by combustion synthesis.

[0057] The phase structure and microstructure of the obtained MoSi2-ZrSi2-ZrB2 powder without in-situ rapid microcrystallization treatment are as follows: Figure 2 and Figure 7As shown in Table 1, to further compare and verify the quality of the powder, the matrix loss rate of the powder obtained in Comparative Example 1 after coating and static oxidation at 1700℃ is shown in Table 1.

[0058] It can be observed that the MoSi2-ZrSi2-ZrB2 powder of Comparative Example 1, which did not undergo in-situ rapid microcrystallization treatment, does not contain oxygen. After coating, the powder sample without in-situ rapid microcrystallization treatment lacks surface microcrystals that can act as a particle binder and antioxidant layer. This prevents the coating from becoming denser and provides a physical barrier that directly resists oxygen penetration, resulting in poor oxygen barrier properties and an increased matrix loss rate.

[0059] Table 1 shows the matrix loss rate of the obtained powder after coating and static oxidation at 1700℃.

[0060] <![CDATA[Matrix loss rate / 10 -6 ·g·cm -2 ·s -1 > Example 1 2.12 Example 2 1.26 Example 3 1.34 Example 4 1.58 Comparative Example 1 4.03

[0061] Table 1

[0062] This invention overcomes the problem of uneven microcrystallization on the powder surface during traditional direct heating methods, and has the advantage of in-situ rapid microcrystallization treatment, which greatly shortens the microcrystallization cycle and alleviates the formation of self-generated defects in the powder caused by in-situ oxidation to a certain extent. Furthermore, during coating treatment, the surface microcrystallization of the powder treated with in-situ rapid microcrystallization can act as a particle binder and an antioxidant layer, promoting the densification of the coating structure while also directly providing a physical barrier against oxygen penetration, thus enhancing the oxygen barrier properties of the antioxidant coating structure.

[0063] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An in-situ rapid microcrystallization treatment method of MoSi2-ZrSi2-ZrB2 composite powder for carbon-based composite material surface oxidation-resistant coating, characterized in that, Specifically, the following steps are included: 1) Powder preparation and loading: The MoSi2-ZrSi2-ZrB2 powder prepared by combustion synthesis was crushed and loaded into a high-temperature quartz glass test tube, and then fitted with a graphite sleeve. 2) Placement and start-up of the induction heating furnace: Place the test tube into the coil of the induction heating furnace, turn on the induction heating furnace, and perform in-situ rapid microcrystallization treatment; 3) Perform in-situ rapid microcrystallization treatment: Start the in-situ rapid microcrystallization treatment and allow it to cool naturally after the treatment is completed; 4) Cooling and product processing: After cooling to room temperature, the powder product in the test tube is separated and ground evenly to obtain MoSi2-ZrSi2-ZrB2 powder with in-situ rapid microcrystallization treatment.

2. The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder for surface antioxidant coating of carbon-based composite materials according to claim 1, characterized in that: The amount of powder filling in step 1) is 5g to 20g.

3. The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder for surface antioxidant coating of carbon-based composite materials according to claim 1, characterized in that: The in-situ rapid microcrystallization treatment temperature in step 3) is 750–900℃.

4. The in-situ rapid microcrystallization method for MoSi2-ZrSi2-ZrB2 composite powder for surface anti-oxidation coating of carbon-based composite materials according to claim 1, characterized in that: The in-situ rapid microcrystallization treatment time in step 3) is 150-300s.

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