Wide-temperature-zone gradient protective coating with cobweb bionic structure and preparation method of wide-temperature-zone gradient protective coating

Abstract

The invention discloses a wide-temperature-range gradient protective coating with a cobweb bionic structure and a preparation method thereof, and in the surface cobweb bionic structure, a cobweb structure phase is an oxide phase, and the rest phase is a high-boron glass phase. The preparation method comprises the steps of raw material mixing, densification treatment, polishing and high-temperature oxidation treatment. Compared with the prior art, the method has the advantages that on the basis of the idea of a surface cobweb bionic structure, through bionic of a cobweb structure and a transition metal oxide grid framework, the high-content liquid glass phase is fixed by utilizing the surface tension of the liquid glass phase according to the liquid locking and fixing effect of the liquid glass phase at a high temperature; the sealing effect is achieved, oxygen penetration and permeation are resisted, the sealing protection effect is achieved, and the advantage of improving the wide-temperature-zone protection effect of the coating is achieved.

Description

Technical Field

[0001] The present invention relates to the field of coating structure design, in particular to a wide temperature range gradient protective coating with a surface spider web bionic structure and a preparation method thereof Background Art

[0002] With the development of future science and technology such as deep earth, deep sea and deep space, various fields have more stringent requirements for high temperature strength and oxidation resistance of materials. Carbon materials not only exhibit excellent high temperature mechanical properties, but are also structural materials that can continue to be used in environments exceeding 3000°C. Carbon materials have extremely low density and can effectively reduce the mass of aircraft. However, without any antioxidant treatment, carbon materials begin to oxidize in an aerobic environment at 400°C, and rapidly oxidize at 500°C, resulting in a shortened service life or even failure of the carbon material. The coating can effectively isolate the carbon material from contact with external oxygen, thereby achieving oxidation protection for a longer time and at higher temperatures.

[0003] The protective coating technology can effectively isolate the carbon material from the external oxygen, thus achieving the oxidation protection effect that can continuously ensure the service capability of the material for a longer time and at a higher temperature. Since the oxygen diffusion coefficient of SiO2 is low, it is 10-13 g·cm at 1200°C. -2 ·s -1 , so it can effectively provide protection for the carbon matrix during the oxidation process. SiO2 generated by the oxidation of silicide is amorphous at high temperatures and has good fluidity. It can form a protective film on the surface of the material, effectively preventing oxygen from contacting and reacting with the internal material. Among these silicides, MoSi2 has shown antioxidant properties that exceed other silicide coatings in many studies. Thanks to the fact that the metal oxide MoO3 generated by MoSi2 is extremely volatile at high temperatures and does not affect the flow and spreading of SiO2, the growth and development of the glass film during the oxidation process is more uniform and sufficient, forming a denser and more stable internal structure, showing better antioxidant ability. Based on this, boride-MoSi2-based high-temperature resistant protective coatings represented by MoSi2 show great potential in high-temperature oxidation protection.

[0004] Yang Qingqing et al. (Yang Qingqing. Research on the Antioxidation Mechanism of MoSi2-HfB2-SiC Coating [D]. China University of Mining and Technology, 2022) used a boride-MoSi2-based gradient protective coating to effectively protect carbon materials by pre-oxidation of the coating, and showed good anti-oxidation effect in an ultra-high temperature environment of 1700°C. However, in the early stage of pre-oxidation film formation of the coating, oxygen will quickly penetrate into the structural defects of the coating to form penetrating channel defects; and the pre-oxidation method is based on the oxidation loss of the system's own components, which is not conducive to the sealing and oxygen barrier of the coating. High content boron glass (HCBG), as a special high-temperature resistant glass, has great potential applications in the field of anti-oxidation protection. If a protective layer containing HCBG can be laid on the surface of the coating in advance to form a gradient coating protection structure, it is expected to further broaden the application of boride-silicon-based protective coatings in wide temperature range protection. However, due to the fluidity of the glass phase, its content in the coating system should not be too high (usually less than 20 vol.%), but the optimization effect of a lower content is limited; and a high-content glass phase exhibits strong fluidity during the protection process in a wide temperature range, making it difficult to provide stable protection for a dynamic temperature environment. Therefore, a feasible solution is urgently needed to solve the current problems and improve the good protection effect of the gradient protective coating in a wide temperature range. Summary of the invention

[0005] In order to solve the drawbacks of the above-mentioned prior art, the present invention aims to provide a wide temperature range gradient protective coating with a surface spider web bionic structure and a preparation method thereof.

[0006] The present invention adopts the following technical solutions to achieve the above-mentioned purpose:

[0007] A wide temperature range gradient protective coating with a surface spider web bionic structure, wherein the spider web structure phase is an oxide phase and the remaining phase is an HCBG high-boron glass phase.

[0008] A method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure, specifically comprising the following steps:

[0009] 1) Mixing raw materials: Mix ZrB2, MoSi2, and HCBG powders according to volume ratio to prepare ZrB2-MoSi2-HCBG precursor powder;

[0010] 2) Densification treatment: The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix;

[0011] 3) Polishing: After the treatment is completed, the sample is taken out and the ZrB2-MoSi2-HCBG wide temperature range protective coating is obtained after polishing;

[0012] 4) High-temperature oxidation treatment: The ZrB2-MoSi2-HCBG wide-temperature-range protective coating is placed in a high-temperature oxidation furnace for rapid oxidation treatment to obtain a wide-temperature-range gradient protective coating with a surface spider web bionic structure.

[0013] As a preferred solution, the volume ratio of ZrB2, MoSi2, and HCBG powder raw materials in step 1) is

[0014] 30~32.5:30~32.5:35~40.

[0015] As a preferred solution, the coating densification treatment temperature in step 2) is 1200-1250°C.

[0016] As a preferred solution, the rapid oxidation treatment time in step 4) is 80 to 100 minutes.

[0017] The advantages of the present invention compared with the prior art are: based on the idea of ​​surface spider web bionic structure, through spider web structure bionics, through the transition metal oxide grid architecture for the "liquid locking and fixing" effect of the liquid glass phase at high temperature, and then using the surface tension of the liquid glass phase to fix the high-content liquid glass phase, it plays a sealing role to resist oxygen penetration and sealing protection, which has the advantage of improving the protective effect of the coating in a wide temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the surface morphology of the wide temperature range gradient protective coating with a surface spider web bionic structure obtained in Example 1 of the present invention.

[0019] Figure 2 This is the surface morphology of the wide temperature range gradient protective coating with a surface spider web bionic structure obtained in Example 2 of the present invention.

[0020] Figure 3 This is the surface morphology of the wide temperature range gradient protective coating with a surface spider web bionic structure obtained in Example 3 of the present invention.

[0021] Figure 4 This is the surface morphology of the conventional wide temperature range gradient protective coating obtained in Comparative Example 1 of the present invention.

[0022] Figure 5 This is the surface morphology of the conventional wide temperature range protective coating obtained in Comparative Example 2 of the present invention.

[0023] Figure 6 This is a graph of the oxidation weight gain after wide temperature range protection of the wide temperature range gradient protective coating obtained in Examples 1 to 3 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0024] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0025] Embodiment 1:

[0026] The present embodiment relates to a preferred solution for a wide temperature range gradient protective coating having a surface spider web bionic structure, wherein the spider web structure phase in the surface spider web bionic structure is an oxide phase and the remaining phase is an HCBG glass phase.

[0027] A method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure as described above is carried out according to the following steps:

[0028] (1) ZrB2, MoSi2, and HCBG powders were mixed in a volume ratio of 32.5:32.5:35 to prepare a ZrB2-MoSi2-HCBG precursor powder with a volume ratio of 32.5:32.5:35.

[0029] (2) The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix at 1200°C.

[0030] (3) After the treatment is completed, the sample is taken out and polished to obtain the ZrB2-MoSi2-HCBG wide temperature range protective coating.

[0031] (4) The ZrB2-MoSi2-HCBG wide temperature range protective coating was placed in a high temperature oxidation furnace for 80 minutes of rapid oxidation treatment to obtain a wide temperature range gradient protective coating with a surface spider web bionic structure.

[0032] This embodiment provides a preferred ratio of a wide temperature range gradient protective coating with a surface spider web bionic structure and a preparation method thereof, wherein the surface morphology is as follows Figure 1 As shown, the oxidation weight gain results after wide temperature range protection are as follows Figure 6 As shown in the figure, it can be seen that the high temperature resistant protective coating provided in this embodiment exhibits a significant spider web structure. Thanks to the surface spider web bionic structure, the gradient protective coating of this embodiment exhibits a good protective effect in a wide temperature range.

[0033] Embodiment 2:

[0034] The present embodiment relates to a preferred solution for a wide temperature range gradient protective coating having a surface spider web bionic structure, wherein the spider web structure phase in the surface spider web bionic structure is an oxide phase and the remaining phase is an HCBG glass phase.

[0035] A method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure as described above is carried out according to the following steps:

[0036] (1) ZrB2, MoSi2, and HCBG powders were mixed in a volume ratio of 31.25:31.25:37.5 to prepare a ZrB2-MoSi2-HCBG precursor powder with a volume ratio of 31.25:31.25:37.5.

[0037] (2) The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix at 1225°C.

[0038] (3) After the treatment is completed, the sample is taken out and polished to obtain the ZrB2-MoSi2-HCBG wide temperature range protective coating.

[0039] (4) The ZrB2-MoSi2-HCBG wide temperature range protective coating was placed in a high temperature oxidation furnace for rapid oxidation treatment for 90 minutes to obtain a wide temperature range gradient protective coating with a surface spider web bionic structure.

[0040] This embodiment provides a preferred ratio of a wide temperature range gradient protective coating with a surface spider web bionic structure and a preparation method thereof, wherein the surface morphology is as follows Figure 2 As shown, the oxidation weight gain results after wide temperature range protection are as follows Figure 6 As shown in the figure, it can be seen that the high temperature resistant protective coating provided in this embodiment exhibits a significant spider web structure. Thanks to the surface spider web bionic structure, the gradient protective coating of this embodiment exhibits a good protective effect in a wide temperature range.

[0041] Embodiment 3:

[0042] The present embodiment relates to a preferred solution for a wide temperature range gradient protective coating having a surface spider web bionic structure, wherein the spider web structure phase in the surface spider web bionic structure is an oxide phase and the remaining phase is an HCBG glass phase.

[0043] A method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure as described above is carried out according to the following steps:

[0044] (1) ZrB2, MoSi2, and HCBG powders were mixed in a volume ratio of 30:30:40 to prepare a ZrB2-MoSi2-HCBG precursor powder with a volume ratio of 30:30:40.

[0045] (2) The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix at 1250°C.

[0046] (3) After the treatment is completed, the sample is taken out and polished to obtain the ZrB2-MoSi2-HCBG wide temperature range protective coating.

[0047] (4) The ZrB2-MoSi2-HCBG wide temperature range protective coating was placed in a high temperature oxidation furnace for rapid oxidation treatment for 100 minutes to obtain a wide temperature range gradient protective coating with a surface spider web bionic structure.

[0048] This embodiment provides a preferred ratio of a wide temperature range gradient protective coating with a surface spider web bionic structure and a preparation method thereof, wherein the surface morphology is as follows Figure 3 As shown, the oxidation weight gain results after wide temperature range protection are as follows Figure 6 As shown in the figure, it can be seen that the high temperature resistant protective coating provided in this embodiment exhibits a significant spider web structure. Thanks to the surface spider web bionic structure, the gradient protective coating of this embodiment exhibits a good protective effect in a wide temperature range.

[0049] Comparative Example 1:

[0050] This comparative example relates to a conventional wide temperature range gradient protective coating, wherein the coating system does not contain HCBG glass phase, is all ZrB2-MoSi2 ceramic phase, and its surface does not have a surface spider web bionic structure.

[0051] A method for preparing the conventional wide temperature range gradient protective coating as described above is carried out according to the following steps:

[0052] (1) ZrB2 and MoSi2 powders were mixed in a volume ratio of 50:50 to prepare a ZrB2-MoSi2 precursor powder with a volume ratio of 50:50.

[0053] (2) The ZrB2-MoSi2 precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix at 1200°C.

[0054] (3) After the treatment is completed, the sample is taken out and polished to obtain a ZrB2-MoSi2 protective coating.

[0055] (4) The ZrB2-MoSi2 wide temperature range protective coating is placed in a high temperature oxidation furnace for 80 minutes of rapid oxidation treatment to obtain a conventional wide temperature range gradient protective coating.

[0056] This comparative example provides a conventional wide temperature range gradient protective coating and a preparation method thereof, wherein the surface morphology is as follows Figure 4 As shown, the oxidation weight gain results after wide temperature range protection are as follows Figure 6 As shown in the figure, it can be seen that the system of this comparative example does not contain HCBG, and the surface does not have a surface spider web bionic structure. Compared with Example 1, its wide temperature range protection effect is poor.

[0057] Comparative Example 2:

[0058] This comparative example relates to a conventional wide temperature range protective coating, wherein the coating system has not been subjected to rapid oxidation treatment, and thus its surface does not have a surface spider web bionic structure.

[0059] A method for preparing the conventional wide temperature range protective coating as described above is carried out according to the following steps:

[0060] (1) ZrB2, MoSi2, and HCBG powders were mixed in a volume ratio of 30:30:40 to prepare a ZrB2-MoSi2-HCBG precursor powder with a volume ratio of 30:30:40.

[0061] (2) The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix at 1250°C.

[0062] (3) After the treatment is completed, the sample is taken out and polished to obtain the ZrB2-MoSi2-HCBG conventional wide temperature range protective coating.

[0063] This comparative example provides a conventional wide temperature range protective coating and a preparation method thereof, wherein the surface morphology is as follows Figure 5 As shown, the oxidation weight gain results after wide temperature range protection are as follows Figure 6 Compared with Example 3, the rapid oxidation treatment in step (4) is not performed, so the sample does not form a protective coating with a gradient structure, and therefore does not have a surface spider web bionic structure. Compared with Example 3, its wide temperature range protection effect is poor.

[0064] The present invention and its embodiments are described above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it and do not deviate from the purpose of the invention, they can creatively design a structure and embodiment similar to the technical solution, which should fall within the protection scope of the present invention.

Claims

1. A wide temperature range gradient protective coating with a surface spider web bionic structure, characterized in that: The spider web structure phase in the surface spider web bionic structure is an oxide phase, and the remaining phase is an HCBG glass phase.

2. A method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure, characterized in that: The specific steps include: 1) Mixing raw materials: Mix ZrB2, MoSi2, and HCBG powders according to volume ratio to prepare ZrB2-MoSi2-HCBG precursor powder; 2) Densification treatment: The ZrB2-MoSi2-HCBG precursor powder is loaded into a graphite mold, filled with a carbon matrix, and placed in a low-temperature hot pressing sintering device to perform a densification treatment on the surface coating of the carbon matrix; 3) Polishing: After the treatment is completed, the sample is taken out and the ZrB2-MoSi2-HCBG wide temperature range protective coating is obtained after polishing; 4) High-temperature oxidation treatment: The ZrB2-MoSi2-HCBG wide-temperature-range protective coating is placed in a high-temperature oxidation furnace for rapid oxidation treatment to obtain a wide-temperature-range gradient protective coating with a surface spider web bionic structure.

3. The method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure according to claim 2, characterized in that: In the step 1), the volume ratio of ZrB2, MoSi2 and HCBG powder raw materials is in the range of 30-32.5:30-32.5:35-40.

4. The method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure according to claim 2, characterized in that: The coating densification treatment temperature in step 2) is 1200-1250°C.

5. The method for preparing a wide temperature range gradient protective coating having a surface spider web bionic structure according to claim 2, characterized in that: The rapid oxidation treatment time in step 4) is 80 to 100 minutes.

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