A zirconium diboride-silicon carbide-zirconium silicon gradient ultra-high temperature ceramic coating precursor powder and a preparation method thereof

Abstract

This invention relates to the field of ultra-high temperature ceramic coating precursor powders, specifically a ZrB2-SiC-ZrSi x A method for preparing gradient ultra-high temperature ceramic coating precursor powder. This invention first uses Zr, B4C, and Si as raw materials, mixes them in a specific ratio, and then presses them into briquettes. The pressed material is placed in a combustion synthesis furnace, and a combustion synthesis reaction is initiated in a vacuum environment. After the combustion synthesis reaction is completed, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi. x Gradient-type ultra-high temperature ceramic coating precursor powder. This invention avoids the high-temperature cracking problem caused by the large difference in thermal expansion coefficients between the components and the graphite matrix in traditional alloying systems. This invention overcomes the difficulty of alloying traditional SiC-based systems and synergizes with amorphous overmetallic silicide ZrSi. x The alloying composite has the advantage of achieving high oxygen barrier strengthening by utilizing the multiphase alloying of powder.

Description

Technical Field

[0001] This invention relates to the field of ultra-high temperature ceramic coating precursor powders, specifically a ZrB2-SiC-ZrSi... x Gradientized ultra-high temperature ceramic coating precursor powder and its preparation method. Background Technology

[0002] Carbon-based composite materials possess advantages such as low thermal diffusivity, low coefficient of thermal expansion (CTE), high specific strength and modulus, and excellent thermal shock resistance in inert environments. They are widely used as high-temperature resistant structural materials in global strategic weapons and the aerospace field. However, their susceptibility to oxidation at high temperatures and oxygen embrittlement significantly hinder their application in core components of aerospace equipment. Therefore, improving oxidation protection performance has become a key challenge determining the development and application of carbon structural materials.

[0003] Ultra-high temperature ceramic (UHTC) coatings serve as a barrier between the substrate and the high-temperature, oxygen-containing environment. Their high oxygen-barrier structure is fundamental to enhancing the oxygen barrier capacity of carbon substrates. Among numerous coating systems, boride-silicon based coatings can generate a sealing glass layer in situ on the surface during high-temperature protection. This sealing layer can repair defects caused by in-situ surface oxidation and effectively resist oxygen penetration, thus forming a gradient coating structure. This system is considered one of the most promising UHTC ceramic coating systems. ZrB2, due to its high melting point, low relative density, and high thermal conductivity, is considered the most promising material in this system.

[0004] However, since the static oxygen barrier structure of the coating changes dynamically with the oxidation loss of coating components, when the application temperature exceeds 1627℃, the vigorous release of volatile gases (B2O3, SiO, CO, CO2) generated by the active oxidation of the coating leads to a large number of oxidation defects in the oxygen barrier barrier, resulting in a destructive evolution of the coating's oxygen barrier structure and greatly weakening the coating's oxidation protection capability. The oxidation porosity of the coating during the oxidation process, leading to an increase in oxidative active sites, is the fundamental reason for the dynamic evolution of the oxygen barrier structure of the ZrB2-SiC coating. To enhance the dynamic stability of the coating, it is urgent to slow down the oxidation porosity of the coating to improve its oxidation protection and porosity repair capabilities.

[0005] Alloying modification of powders is one of the feasible technologies to effectively improve the protective quality of coatings. Existing technologies, such as CN113087530A, disclose a high oxygen barrier coating based on ZrB2 non-equilibrium alloying modification and its preparation method. Although this method successfully synthesizes high-quality non-equilibrium alloyed powders and alleviates the repair aging problem caused by component separation through alloying, thus improving the coating's oxidation repair efficiency, the significant difference in thermal expansion coefficients between ZrB2 and MoSi2 and the graphite matrix leads to easy detachment and cracking of the coating from the carbon matrix during high-temperature protection, damaging the oxygen barrier structure and deteriorating the protective effect. Research has found that SiC has a lower thermal expansion coefficient than ZrB2 and transition metal silicides and can also provide a stable Si source, effectively mitigating cracking caused by thermal stress between the coating and the substrate during protection. However, SiC cannot be synthesized by self-propagating combustion of elemental Si and C powder, making it difficult to form SiC-based alloyed powders. Therefore, oxygen barrier systems containing SiC often use secondary mechanical mixing, which severely inhibits the alloying effect of composite powders.

[0006] Therefore, there is an urgent need for a method to alloy SiC-based composite powders in order to solve the existing technical problems. Summary of the Invention

[0007] The objective of this invention is to provide a ZrB2-SiC-ZrSi x A method for preparing gradient ultra-high temperature ceramic coating precursor powders addresses the challenge of directly synthesizing SiC-based powders using Si and C via self-propagation by employing B4C as a raw material. Simultaneously, by adding excess Zr and Si during briquetting, amorphous overmetallic silicides ZrSi are generated during combustion. x The advantages of high oxygen barrier strengthening are achieved through the split-phase multiphase alloying.

[0008] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0009] A ZrB2-SiC-ZrSi x The gradient ultra-high temperature ceramic coating precursor powder is a high oxygen barrier reinforced multiphase alloyed powder.

[0010] As an improvement, the ZrSi x It manifests as one or more of ZrSi, ZrSi2, and Zr5Si4.

[0011] As an improvement, the ZrB2-SiC-ZrSi x The volume ratio range of the gradient ultra-high temperature ceramic coating precursor powder is: ZrB2:SiC:ZrSi x =196:98:2~180:90:10;

[0012] The preparation method of this invention is as follows: Zr, B4C, and Si are used as raw materials for briquetting and combustion synthesis. By adding excess Zr and Si, an amorphous permetallic silicide ZrSi is generated during the combustion process. x After crushing, ZrB2-SiC-ZrSi is obtained. x Gradientized ultra-high temperature ceramic coating precursor powder.

[0013] As an improvement, the specific method is as follows:

[0014] (1) Using Zr, B4C and Si as raw materials, mix them in proportion and then press them into blocks;

[0015] (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment;

[0016] (3) After the combustion synthesis reaction is complete, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi. x Gradientized ultra-high temperature ceramic coating precursor powder.

[0017] As an improvement, the mass ratio range of the Zr, B4C, and Si raw materials is as follows:

[0018] Zr:B4C:Si=80.3:6.6:13.1~77.2:5.8:17.

[0019] As an improvement, the ZrB2-SiC-ZrSi x The volume ratio range of the gradient ultra-high temperature ceramic coating precursor powder is: ZrB2:SiC:ZrSi x =196:98:2~180:90:10.

[0020] The advantages of this invention are:

[0021] This invention uses B4C as a raw material for briquetting and combustion synthesis, effectively solving the problem that SiC-based powders cannot be directly synthesized from Si and C through self-propagation. Simultaneously, this invention avoids the high-temperature cracking problem caused by the large difference in thermal expansion coefficients between the components and the graphite matrix in traditional alloying systems, and overcomes the difficulty of alloying traditional SiC-based systems. Furthermore, it synergizes with the amorphous overmetallic silicide ZrSi. x The alloying composite has the advantage of achieving high oxygen barrier strengthening by utilizing the multiphase alloying of powder. Attached Figure Description

[0022] Figure 1 The X-ray diffraction phase analysis results of the powder obtained in Example 1 of this invention are shown.

[0023] Figure 2The results of X-ray diffraction phase analysis of powder obtained in Example 2 of this invention are shown.

[0024] Figure 3 The X-ray diffraction phase analysis results of the powder obtained in Example 3 of this invention are shown.

[0025] Figure 4 The X-ray diffraction phase analysis results of the powder obtained in Comparative Example 1 of this invention are shown. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0027] Example 1

[0028] This embodiment involves a ZrB2-SiC-ZrSi x The gradient ultra-high temperature ceramic coating precursor powder has a volume ratio range of ZrB2:SiC:ZrSi. x =196:98:2

[0029] A ZrB2-SiC-ZrSi as described above x A method for preparing gradient ultra-high temperature ceramic coating precursor powder includes:

[0030] (1) Using Zr, B4C and Si as raw materials, they are mixed in a mass ratio of 80.3:6.6:13.1 and then pressed into blocks;

[0031] (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment;

[0032] (3) After the combustion synthesis reaction is complete, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi with a volume ratio of 196:98:2. x Gradientized ultra-high temperature ceramic coating precursor powder.

[0033] This embodiment provides a ZrB2-SiC-ZrSi x The optimal formulation and preparation method of gradient ultra-high temperature ceramic coating precursor powder, and its phase structure are as follows: Figure 1 As shown in Table 1, the results of the static oxidation protection efficiency of the powder obtained in Example 1 after coating at 1700℃ are shown in Table 1.

[0034] Example 2:

[0035] This embodiment involves a ZrB2-SiC-ZrSi xThe gradient ultra-high temperature ceramic coating precursor powder has a volume ratio range of ZrB2:SiC:ZrSi. x =190:95:5

[0036] A ZrB2-SiC-ZrSi as described above x A method for preparing gradient ultra-high temperature ceramic coating precursor powder includes:

[0037] (1) Using Zr, B4C and Si as raw materials, they are mixed in a mass ratio of 78.8:6.5:14.8 and then pressed into blocks;

[0038] (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment;

[0039] (3) After the combustion synthesis reaction is complete, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi with a volume ratio of 190:95:5. x Gradientized ultra-high temperature ceramic coating precursor powder.

[0040] This embodiment provides a ZrB2-SiC-ZrSi x The optimal formulation and preparation method of gradient ultra-high temperature ceramic coating precursor powder, and its phase structure are as follows: Figure 2 As shown in Table 1, the results of the static oxidation protection efficiency of the powder obtained in Example 2 after coating at 1700℃ are shown in Table 1.

[0041] Example 3:

[0042] This embodiment involves a ZrB2-SiC-ZrSi x The gradient ultra-high temperature ceramic coating precursor powder has a volume ratio range of ZrB2:SiC:ZrSi. x =180:90:10

[0043] A ZrB2-SiC-ZrSi as described above x A method for preparing gradient ultra-high temperature ceramic coating precursor powder includes:

[0044] (1) Using Zr, B4C and Si as raw materials, they are mixed in a mass ratio of 77.2:5.8:17 and then pressed into blocks;

[0045] (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment;

[0046] (3) After the combustion synthesis reaction is complete, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi with a volume ratio of 180:90:10. x Gradientized ultra-high temperature ceramic coating precursor powder.

[0047] This embodiment provides a ZrB2-SiC-ZrSi x The optimal formulation and preparation method of gradient ultra-high temperature ceramic coating precursor powder, and its phase structure are as follows: Figure 3 As shown in Table 1, the results of the static oxidation protection efficiency of the powder obtained in Example 3 after coating at 1700℃ are shown in Table 1.

[0048] Comparative Example 1:

[0049] This embodiment involves a ZrB2-SiC gradient ultra-high temperature ceramic coating precursor powder with a volume ratio of ZrB2:SiC = 2:1, meaning it does not contain amorphous overmetallic silicide ZrSi. x Alloyed composites.

[0050] A ZrB2-SiC-ZrSi as described above x A method for preparing gradient ultra-high temperature ceramic coating precursor powder includes:

[0051] (1) Using Zr, B4C and Si as raw materials, they are mixed in a mass ratio of 71.36:17.68:10.96 and then pressed into blocks;

[0052] (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment;

[0053] (3) After the combustion synthesis reaction is completed, the product is taken out and after secondary crushing, ZrB2-SiC gradient ultra-high temperature ceramic coating precursor powder with a volume ratio of 2:1 is obtained.

[0054] This embodiment provides a ZrSi solution that does not contain amorphous overmetal silicides. x The optimal formulation and preparation method of alloyed composite ZrB2-SiC gradient ultra-high temperature ceramic coating precursor powder, and its phase structure are as follows. Figure 4 As shown. Since Zr and Si were not added in excess in this embodiment, the product of this embodiment does not contain amorphous overmetallic silicide ZrSi. x The results of the static oxidation protection efficiency of the powder obtained in Comparative Example 1 after coating at 1700℃ are shown in Table 1.

[0055] Compared to Examples 1-3, this comparative example does not contain amorphous overmetallic silicide ZrSi. x The composition, namely containing only ZrB2-SiC, cannot simultaneously achieve thermal stress relief and high oxygen barrier enhancement after the powder sample is coated. As a result, the static oxidation protection efficiency of the powder obtained in Comparative Example 1 at 1700℃ after coating is significantly lower than that in Examples 1 to 3, and the dynamic stability of the oxygen barrier structure of the coating is poor.

[0056] Table 1 Results of oxidative weight gain and oxidative protection efficiency at 1700℃

[0057] Protection efficiency / % Example 1 98.36 Example 2 98.73 Example 3 97.95 Comparative Example 1 97.16

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A ZrB2-SiC-ZrSi x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, characterized in that, It is carried out according to the following steps: (1) Using Zr, B4C and Si as raw materials, mix them in proportion and then press them into blocks; (2) Place the briquetted material into a combustion synthesis furnace and start the combustion synthesis reaction in a vacuum environment; (3) After the combustion synthesis reaction is complete, the product is removed and subjected to secondary crushing to obtain ZrB2-SiC-ZrSi. x Gradientized ultra-high temperature ceramic coating precursor powder; The mass ratio range of the Zr, B4C, and Si raw materials is Zr:B4C:Si = 80.3:6.6:13.1 to 77.2:5.8:

17.

2. The ZrB2-SiC-ZrSi according to claim 1 x A method for preparing gradient ultra-high temperature ceramic coating precursor powder, characterized in that, ZrSi x It manifests as one or more of ZrSi, ZrSi2, and Zr5Si4.

3. A ZrB2-SiC-ZrSi according to claim 1 x A method for preparing gradient ultra-high temperature ceramic coating precursor powder, characterized in that, The ZrB2-SiC-ZrSi x The volume ratio range of the gradient ultra-high temperature ceramic coating precursor powder is: ZrB2 :SiC :ZrSi x =196:98:2~180:90:10.

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