ZrB2-SiC-ZrSix gradient ultra-high-temperature ceramic coating precursor powder and preparation method thereof

Abstract

The invention relates to the field of superhigh-temperature ceramic coating precursor powder, in particular to a preparation method of ZrB2-SiC-ZrSix gradient superhigh-temperature ceramic coating precursor powder. The preparation method comprises the following steps: firstly, taking Zr, B4C and Si as raw materials, mixing according to a proportion, and then briquetting; and putting the briquetting material into a combustion synthesis furnace, and starting a combustion synthesis reaction in a vacuum environment. And after the combustion synthesis reaction is finished, taking out a product, and carrying out secondary crushing to obtain ZrB2-SiC-ZrSix gradient ultra-high-temperature ceramic coating precursor powder. The problem of high-temperature cracking caused by large difference of thermal expansion coefficients of components of a traditional alloying system and a graphite matrix is avoided. The problem that a traditional SiC-based system is difficult to alloy is solved, alloying compounding of the amorphous metal silicide ZrSix is coordinated, and the high-oxygen-barrier strengthening method has the advantage that high-oxygen-barrier strengthening is achieved through multiphase alloying of powder.

Description

Technical Field

[0001] The present invention relates to the field of ultra-high temperature ceramic coating precursor powder, specifically a ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder and preparation method thereof. Background Art

[0002] Carbon-based composite materials have the advantages of low thermal diffusivity, low coefficient of thermal expansion (CTE), high specific strength and modulus, and excellent thermal shock resistance in an inert environment. They are widely used as one of the high-temperature resistant structural materials urgently needed in the global strategic weapons and aviation fields. However, high-temperature oxidation and oxygen embrittlement have greatly hindered their application in core components of aviation equipment. Therefore, improving oxidation protection performance has become a key problem that determines 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 environment. The construction of their high oxygen barrier structure is the basis and guarantee for improving the oxygen barrier capacity of the carbon matrix. Among many 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 the defects caused by in-situ oxidation of the surface and effectively resist oxygen penetration, thereby forming a gradient coating structure. This system is considered to be one of the most promising ultra-high temperature ceramic coating systems. ZrB2 is considered the most promising system material due to its high melting point, low relative density and high thermal conductivity.

[0004] However, since the static oxygen barrier structure of the coating changes dynamically with the oxidation loss of the coating components, when the application temperature exceeds 1627°C, the violent release of volatile gases (B2O3, SiO, CO, CO2) produced by the active oxidation of the coating will cause a large number of oxidation defects in the coating oxygen barrier, which will cause destructive changes in the coating oxygen barrier structure, greatly weakening the oxidation protection ability of the coating. The oxidation loosening of the coating during the oxidation process leads to an increase in oxidation active sites, which is the fundamental reason for the dynamic evolution of the oxygen barrier structure of the ZrB2-SiC coating. In order to enhance the dynamic stability of the coating, it is urgent to slow down the oxidation loosening of the coating to improve the oxidation protection and loosening repair capabilities.

[0005] Alloying modification of powder is one of the feasible technologies to effectively improve the quality of coating protection. Existing technologies such as CN113087530A disclose a high oxygen barrier coating and preparation method based on ZrB2 non-equilibrium alloying modification. Although the method is used to synthesize high-quality non-equilibrium alloyed powder, the repair aging problem caused by component separation is alleviated by alloying, and the coating oxidation repair efficiency is improved. However, due to the large difference in thermal expansion coefficients between ZrB2 and MoSi2 and the graphite matrix in its components, the coating is easy to separate from the carbon matrix and crack during high-temperature protection, destroying the oxygen barrier structure and deteriorating the protection effect. Studies have found that SiC has a lower thermal expansion coefficient than ZrB2 and transition metal silicides, and can also provide a stable Si source, which can effectively slow down the cracking caused by thermal stress between the coating and the matrix during the protection process. However, SiC cannot use Si single substance and C powder for self-propagating combustion synthesis, and it is difficult to form SiC-based alloyed powder. Therefore, the oxygen barrier system containing SiC addition is mostly used for secondary mechanical mixing, which seriously inhibits the effect of composite powder alloying.

[0006] Based on this, there is an urgent need for a method for alloying SiC-based composite powders to solve the existing technical problems. Summary of the invention

[0007] The purpose of the present invention is to provide a ZrB2-SiC-ZrSi x The preparation method of the gradient ultra-high temperature ceramic coating precursor powder solves the problem that SiC-based powder cannot be directly synthesized by self-propagating with Si and C by using B4C as the raw material. At the same time, by adding excessive Zr and Si during the briquetting process, an amorphous metal silicide ZrSi is generated during the combustion process. x , the split-phase multi-phase alloying achieves the advantage of high oxygen resistance strengthening.

[0008] In order to achieve the above technical purpose, the technical solution of the present invention is as follows:

[0009] A ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder, the ultra-high temperature ceramic coating precursor powder is a high oxygen resistance strengthened multi-phase alloy powder.

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

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

[0012] The preparation method of the present invention comprises: using Zr, B4C and Si as raw materials for briquetting and combustion synthesis, and generating an amorphous metal silicide ZrSi by adding excessive Zr and Si in the combustion process. x , after crushing, ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder.

[0013] As an improvement, the specific method is carried out according to the following steps:

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

[0015] (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment;

[0016] (3) After the combustion synthesis reaction is completed, the product is taken out and crushed twice to obtain ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder.

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

[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 of the gradient ultra-high temperature ceramic coating precursor powder is as follows: ZrB2:SiC:ZrSi x =196:98:2~180:90:10.

[0020] The present invention has the advantages that:

[0021] The present invention uses B4C as a raw material for briquetting and combustion synthesis, which can effectively solve the problem that SiC-based powders cannot be directly synthesized by direct self-propagation of Si and C. At the same time, the present invention avoids the high-temperature cracking problem caused by the large difference in thermal expansion coefficients between the components of the traditional alloying system and the graphite matrix, and overcomes the difficulty of alloying the traditional SiC-based system, and cooperates with the amorphous metal silicide ZrSi x The alloy composite has the advantage of achieving high oxygen resistance strengthening by utilizing the multi-phase alloying of powders. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the powder X-ray diffraction phase analysis result obtained in Example 1 of the present invention.

[0023] Figure 2This is the powder X-ray diffraction phase analysis result obtained in Example 2 of the present invention.

[0024] Figure 3 This is the powder X-ray diffraction phase analysis result obtained in Example 3 of the present invention.

[0025] Figure 4 This is the powder X-ray diffraction phase analysis result obtained in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0027] Example 1

[0028] This embodiment involves a ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder, the volume ratio range is: ZrB2:SiC:ZrSi x =196:98:2

[0029] A ZrB2-SiC-ZrSi x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, comprising:

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

[0031] (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment;

[0032] (3) After the combustion synthesis reaction is completed, the product is taken out and crushed twice to obtain ZrB2-SiC-ZrSi with a volume ratio of 196:98:2 x Gradient ultra-high temperature ceramic coating precursor powder.

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

[0034] Embodiment 2:

[0035] This embodiment involves a ZrB2-SiC-ZrSi xGradient ultra-high temperature ceramic coating precursor powder, the volume ratio range is: ZrB2:SiC:ZrSi x =190:95:5

[0036] A ZrB2-SiC-ZrSi x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, comprising:

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

[0038] (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment;

[0039] (3) After the combustion synthesis reaction is completed, the product is taken out and crushed twice to obtain ZrB2-SiC-ZrSi with a volume ratio of 190:95:5 x Gradient ultra-high temperature ceramic coating precursor powder.

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

[0041] Embodiment 3:

[0042] This embodiment involves a ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder, the volume ratio range is: ZrB2:SiC:ZrSi x =180:90:10

[0043] A ZrB2-SiC-ZrSi x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, comprising:

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

[0045] (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment;

[0046] (3) After the combustion synthesis reaction is completed, the product is taken out and crushed twice to obtain ZrB2-SiC-ZrSi with a volume ratio of 180:90:10 x Gradient ultra-high temperature ceramic coating precursor powder.

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

[0048] Comparative Example 1:

[0049] The present embodiment relates to a ZrB2-SiC gradient ultra-high temperature ceramic coating precursor powder, the volume ratio of which is: ZrB2:SiC=2:1, that is, it does not contain amorphous metal silicide ZrSi x alloy composite.

[0050] A ZrB2-SiC-ZrSi x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, comprising:

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

[0052] (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment;

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

[0054] This embodiment provides a method of providing a ZrSi x The preferred ratio and preparation method of the alloyed composite ZrB2-SiC-gradient ultra-high temperature ceramic coating precursor powder, the physical structure of which is as follows Figure 4 Since Zr and Si are not added in excess in this embodiment, the product of this embodiment does not contain amorphous metal silicide ZrSi x The results of the 1700°C ultra-high temperature static oxidation protection efficiency of the powder obtained in Comparative Example 1 after coating are shown in Table 1.

[0055] Compared with Examples 1 to 3, this comparative example does not contain amorphous metal silicide ZrSi x Component, that is, it only contains ZrB2-SiC component. In this state, the powder sample cannot take into account both thermal stress release and high oxygen barrier enhancement after coating, resulting in the 1700°C ultra-high temperature static oxidation protection efficiency of the powder obtained in comparative example 1 after coating being significantly lower than that of embodiments 1 to 3, and the dynamic stability of the oxygen barrier structure of the coating is poor.

[0056] Table 1 Results of oxidation weight gain and oxidation 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 specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder, characterized in that: The ultra-high temperature ceramic coating precursor powder is a high oxygen-barrier reinforced multiphase alloy powder.

2. A ZrB2-SiC-ZrSi according to claim 1 x Gradient ultra-high temperature ceramic coating precursor powder, characterized in that: The ZrSi x It can be one or more of ZrSi, ZrSi2, and Zr5Si4.

3. A ZrB2-SiC-ZrSi according to claim 1 x Gradient ultra-high temperature ceramic coating precursor powder, characterized by: The ZrB2-SiC-ZrSi x The volume ratio of the gradient ultra-high temperature ceramic coating precursor powder is as follows: ZrB2:SiC:ZrSi x =196:98:2~180:90:

10.

4. A ZrB2-SiC-ZrSi according to claim 1 x The method for preparing a gradient ultra-high temperature ceramic coating precursor powder is characterized in that: Zr, B4C, and Si are used as raw materials for briquetting and combustion synthesis. By adding excessive Zr and Si, an amorphous metal silicide ZrSi is generated during the combustion process. x , after crushing, ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder.

5. A ZrB2-SiC-ZrSi according to claim 4 x The method for preparing a gradient ultra-high temperature ceramic coating precursor powder is characterized in that: It proceeds as follows: (1) Using Zr, B4C and Si as raw materials, mixing them in proportion and then pressing them into blocks; (2) placing the briquette material into a combustion synthesis furnace and starting a combustion synthesis reaction in a vacuum environment; (3) After the combustion synthesis reaction is completed, the product is taken out and crushed twice to obtain ZrB2-SiC-ZrSi x Gradient ultra-high temperature ceramic coating precursor powder.

6. A ZrB2-SiC-ZrSi according to claim 5 x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, characterized in that: The mass ratio of the Zr, B4C and Si raw materials is in the range of Zr:B4C:Si=80.3:6.6:13.1 to 77.2:5.8:

17.

7. A ZrB2-SiC-ZrSi according to claim 5 x A method for preparing a gradient ultra-high temperature ceramic coating precursor powder, characterized in that: The ZrB2-SiC-ZrSi x The volume ratio of the gradient ultra-high temperature ceramic coating precursor powder is as follows: ZrB2:SiC:ZrSi x =196:98:2~180:90:10.

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