Boron-containing carbide ceramic for high-temperature aerobic environment and preparation method thereof

Abstract

The invention discloses boron-containing carbide ceramic for a high-temperature aerobic environment and a preparation method of the boron-containing carbide ceramic, and belongs to the technical field of carbide ceramic. The ceramic is (HfnTam) (CxBy), Hf and Ta are adopted as raw materials to prepare carbides, on the basis, boron carbide and boron oxide are added to serve as boron sources, designed carbon vacancies are filled with boron atoms, the crystal structure of the carbides is not changed, meanwhile, redundant oxygen brought by boron oxide is eliminated through boron carbide, and finally boron-containing carbides are formed. In the whole preparation process, powder is prepared only through one-time high-temperature treatment, the ceramic block is prepared through one-time high-temperature sintering, the preparation efficiency is higher, and the prepared boron-containing carbide ceramic block is high in density and shows high oxidation resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbide ceramics, and particularly relates to a boride-containing carbide ceramic for high-temperature oxygen-containing environments and a preparation method thereof. BACKGROUND

[0002] In the petroleum and petrochemical industry, the surface of downhole drill bits and high-temperature corrosion components needs to face extreme high temperatures and strong corrosive media, etc. Carbide ultra-high-temperature ceramics have the characteristics of high melting point, high stability and high-temperature strength, and the use life of key equipment can be prolonged by forming a protective coating on the surface using ceramics. At the same time, the high melting point of carbide ceramics also makes it an important candidate material for aerospace extreme environment thermal protection systems. However, the high-temperature oxidation resistance of traditional binary carbides is poor, which affects their application.

[0003] Hf-Ta system carbides exhibit high strength and high hardness characteristics, can withstand large mechanical stress and wear, and the melting point of Hf-Ta system carbides is as high as 3900 DEG C, so that the system carbide can still maintain good performance at high temperatures, and has good corrosion resistance, and can be used for a long time in harsh environments. However, its oxidation resistance is weak, for example, the HfO2 layer formed by the oxidation of HfC below 1800 DEG C has a porous structure, which is difficult to prevent external oxygen from oxidizing the material. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a boride-containing carbide ceramic for high-temperature oxygen-containing environments and a preparation method thereof, so as to solve the problem of poor oxidation resistance of carbide powder in high-temperature environments in the prior art.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted:

[0006] A preparation method of a boride-containing carbide ceramic for high-temperature oxygen-containing environments, comprising the following steps:

[0007] Step 1, mixing Hf powder, Ta powder and carbon powder, heat treatment after ball milling, and obtaining (Hf n Ta m )C x powder after crushing;

[0008] Step 2, ball milling and mixing (Hf n Ta m )C x powder and boron source, drying treatment after ball milling, obtaining a mixture, and obtaining (Hf n Ta m )(C x B yceramic; wherein n / m=1 / 1~4 / 1, 0.7<=x<=0.9, 0.05<=y<=0.3, x+y<=0.97.

[0009] The boron source includes boron carbide and boron oxide.

[0010] The further improvement of the present application is:

[0011] Preferably, in step 1, the heat treatment temperature is 1100~1400℃, and the heat treatment time is >=15min.

[0012] Preferably, in step 2, the molar ratio of boron carbide to boron oxide in the boron source is 3:(2~1).

[0013] Preferably, in step 1, the ball milling speed is 50~200rpm, and the ball milling time is 1~5h.

[0014] Preferably, in step 2, the ball milling speed is 200~300rpm, and the ball-to-material ratio is 4:1~10:1.

[0015] Preferably, in step 2, the mixture is sintered by spark plasma sintering to obtain (Hf n Ta m )(C x B y ) ceramic; during the spark plasma sintering process, the sintering temperature is 1600~2000℃, the sintering time is 10~30min, and the pressure is 40~60MPa.

[0016] A boron-containing carbide ceramic for high-temperature aerobic environment prepared by any of the above preparation methods, the boron-containing carbide ceramic has a structural formula of (Hf n Ta m )(C x B y ), and the boron-containing carbide ceramic has a face-centered cubic structure, and part of carbon vacancy lattices are replaced by boron.

[0017] wherein n / m=1 / 1~4 / 1, 0.7<=x<=0.9, 0.05<=y<=0.3, x+y<=0.97.

[0018] Preferably, n / m is 3 / 1 or 4 / 1.

[0019] Preferably, 0.70<=x<=0.80, 0.20<=y<=0.30, x+y<=0.90.

[0020] Preferably, the boron-containing carbide ceramic is (Hf 0.50 Ta 0.50 )(C 0.80 B 0.10 ), (Hf 2 / 3Ta 1 / 3 )(C 0.60 B 0.30 ) or (Hf 0.75 Ta 0.25 )(C 0.88 B 0.09 ) of any one.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The application discloses a preparation method of boride-containing ceramic for high-temperature oxygen-containing environment. n Ta m )C x powder, which provides a basis for subsequent boron atom diffusion. Then, boron carbide and boron oxide are used as boron sources, and the boron carbide removes the impurity oxygen brought by the boron oxide. After the (Hf n Ta m )C x powder is mixed with the boron sources through ball milling, sintering is performed to form a boride-containing (Hf n Ta m )(C x B y ) block. The method introduces boron into the Hf-Ta powder system, improves the oxidation resistance of the carbide, and only needs one high-temperature treatment process to prepare the powder and one high-temperature sintering process to prepare the ceramic block. Through the double boron sources, the boron element is introduced into the carbide while the impurity oxygen is removed, and the formation of a porous structure is avoided. Compared with the prior art, the method is simpler, greatly reduces the process conditions, has a simple process flow, is high in preparation efficiency, and is beneficial to large-scale production.

[0023] The application further discloses a boride-containing ceramic for high-temperature oxygen-containing environment, which is (Hf n Ta m )(C x B y ). The ceramic is prepared by using Hf and Ta as raw materials to prepare carbide. On this basis, boron carbide and boron oxide are added as boron sources to fill the designed carbon vacancies with boron atoms without changing the crystal structure of the carbide. Meanwhile, the boron carbide removes the excess oxygen brought by the boron oxide, and finally forms the boride-containing carbide. The ceramic material has a face-centered cubic structure, and the ceramic block has high density, and the relative density is greater than 96%. The ceramic block shows strong oxidation resistance under the condition of 1600 DEG C and an oxygen-containing environment. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A macroscopic morphology diagram of a ceramic block prepared in Example 1.

[0025] Figure 2 Surface scanning electron micrograph of the ceramic bulk prepared in Example 1;

[0026] Figure 3 X-ray diffraction spectrum of the ceramic bulk prepared in Example 1;

[0027] Figure 4 Macroscopic morphology of the ceramic bulk prepared in Example 2;

[0028] Figure 5 Surface scanning electron micrograph of the ceramic bulk prepared in Example 2;

[0029] Figure 6 X-ray diffraction spectrum of the ceramic bulk prepared in Example 2. DETAILED DESCRIPTION

[0030] The present application will be further described with reference to the following drawings:

[0031] In order that those skilled in the art can better understand the features and effects of the present application, the following is a general explanation and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the specification have the usual meanings understood by those skilled in the art of the present application, and in the event of a conflict, the definitions in the specification shall prevail.

[0032] In this document, unless otherwise specifically stated, "comprise", "comprises", "comprising", "contain", "contains", "containing", "have", "has", "having", or similar words, encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0033] The present application will be further described with reference to the following drawings:

[0034] The following examples use conventional equipment in the art. Unless otherwise noted, the experimental methods in the following examples are conducted under conventional conditions, or under the conditions recommended by the manufacturer. Various raw materials are used in the following examples, and unless otherwise specified, conventional commercially available products are used, and the specifications are conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0035] The first aspect of the present application provides a preparation method of boride-containing ceramic for high-temperature aerobic environment, comprising the following steps:

[0036] (1) Preparation of carbide powder: Hf powder (purity ≥ 99wt%, particle size is micron or nanometer level), Ta powder (purity ≥ 99wt%, particle size is micron or nanometer level) and carbon powder (purity ≥ 99wt%, particle size is micron or nanometer level) are mixed in a planetary ball mill, not by mechanical alloying. After mixing, the mixture is dried at 30-50℃ and sieved to obtain a mixed powder. The mixed powder is placed in a graphite tank for high-temperature heat treatment, then cooled to room temperature and taken out, and then manually broken to obtain carbide (Hf n Ta m )C x ) powder.

[0037] (2) Preparation of boride-containing ceramic: the carbide powder is ball-mixed with a boron source, and the mixture is dried after being uniformly ball-mixed to obtain a mixture. The mixture is then subjected to high-temperature sintering under a spark plasma sintering condition to obtain a boride-containing ceramic (Hf n Ta m )(C x B y ) ceramic.

[0038] In this process, the composite boron source has the following main functions: first, it provides a composite boron source composed of boron carbide and boron oxide. The carbon atoms in the boron carbide eliminate the oxygen impurities brought by the boron oxide, and under high-temperature conditions, the boron atoms are solid-solved into the carbon vacancy lattice of the carbide. Second, the melting point of boron oxide is low (about 450℃), and part of the boron oxide will volatilize during the high-temperature sintering process, which is not easy to control the boron content in the product. The melting point of boron carbide is high (about 2450℃), and it will not volatilize and consume boron atoms during the sintering process, making it easy to design the total boron atom content in the product.

[0039] Preferably, in step (1), the mixing conditions are: mixing time is 1-5h, medium is ethanol, rotation speed is 50-200rpm, and ball-to-material ratio is 4:1-10:1.

[0040] Preferably, in step (1), the high-temperature heat treatment conditions are: vacuum degree is <5Pa, temperature is 1100-1400℃, holding time is ≥15min, and heating rate is 5-100℃ / min.

[0041] Preferably, in step (2), the boron source is a composite boron source of boron carbide and boron oxide, and the molar ratio of boron carbide to boron oxide is 3 / 2-3 / 1; the purity of boron carbide is ≥99wt%, and the particle size is nanometer level; the purity of boron oxide is ≥99.9wt%.

[0042] Preferably, in step (2), the ball-milling mixing conditions are: time 0.5-2h, medium ethanol, rotation speed 200-300rpm, and ball-to-material ratio 4:1-10:1.

[0043] Preferably, in step (2), the operation conditions of the spark plasma sintering are: vacuum degree ≤5Pa, temperature 1600-2000℃, holding time 10-30min, heating rate 100-200℃ / min, and pressure 40-60MPa.

[0044] The second aspect of the present application provides a boride-containing ceramic for high-temperature aerobic environment, the boride-containing ceramic having a molecular formula of (Hf n Ta m )(C x B y ), wherein n / m=1 / 1-4 / 1, 0.7≤x≤0.9, 0.05≤y≤0.3, and x+y≤0.97, and having a face-centered cubic structure, and the boride-containing ceramic has excellent oxidation resistance at 1600℃ in aerobic environment.

[0045] In the structure, part of the carbon vacancy lattice is occupied by B, so that the face-centered cubic structure is not changed, and the high-temperature sintering performance of the entire boride-containing ceramic is improved due to the introduction of B.

[0046] Preferably, n / m is 3 / 1 and 4 / 1.

[0047] Preferably, 0.70≤x≤0.80, 0.20≤y≤0.30, and x+y≤0.90.

[0048] Preferably, the boride-containing ceramic has one or more of the following molecular formulas: (Hf 0.50 Ta 0.50 )(C 0.80 B 0.10 ), (Hf 2 / 3 Ta 1 / 3 )(C 0.60 B 0.30 ), and (Hf 0.75 Ta 0.25 )(C 0.88 B 0.09 ).

[0049] More preferably, the oxidation resistance of (Hf 0.75 Ta 0.25 )(C 0.88 B 0.09 ) is the best.

[0050] The present application is further illustrated below with reference to specific examples

[0051] Example 1

[0052] (1) Hf powder, Ta powder, and C powder were mixed in a molar ratio of 0.75:0.25:0.88. The mixed powder was then ball-milled in a planetary ball mill for 5 hours. The particle size of Hf powder and Ta powder was <48μm, the particle size of C powder was <3.25μm, and the purity was ≥99%. The ball mill jar and balls were made of cemented carbide. The ball milling medium was ethanol, the rotation speed was 100rpm, and the ball-to-powder ratio was 4:1. After ball milling, the powder was removed, dried at 40℃, and sieved to obtain the mixed powder. The mixed powder was then placed in a graphite jar for high-temperature heat treatment. The process was carried out under vacuum with a vacuum degree of less than 5Pa. The temperature was raised to 1400℃ and held for 15 minutes at a heating rate of 100℃ / min. After cooling to room temperature, the powder was removed and manually crushed to obtain carbide powder.

[0053] (2) Boron carbide and boron oxide were weighed according to a molar ratio of 3:2. The atomic ratio of boron atoms in the added boron source to carbon atoms in the carbide was 0.09:0.88. The mixture was mixed in ethanol for 24 hours at a rotation speed of 200 rpm and a ball-to-material ratio of 4:1. After mixing, the mixture was dried at 40°C to obtain a mixture of boron source and carbide powder. The mixture was placed in a spark plasma sintering furnace for high-temperature sintering under the following conditions: vacuum degree <5 Pa, temperature rise to 1600°C and hold for 30 min, heating rate of 100°C / min, and sintering pressure of 40 MPa. The mixture was then cooled to room temperature and removed to obtain boron-containing carbide ceramic blocks.

[0054] (3) The macroscopic morphology of the prepared boron-containing carbide ceramic bulk is as follows: Figure 1 As shown, the microstructure of the ceramic surface is as follows: Figure 2 As shown, the ceramic surface is dense with no obvious pores, and the X-ray diffraction results of the ceramic are as follows ( Figure 3 The results showed that the boron-containing carbides were similar to TaC and HfC, exhibiting a face-centered cubic structure. ICP-OES elemental analysis revealed that the atomic ratio of Hf, Ta, C, and B in the boron-containing carbides was 0.75:0.25:0.88:0.09. The molecular formula of the boron-containing carbides is (Hf... 0.75 Ta 0.25 (C) 0.88 B 0.09 The relative density of the ceramic block is 96.7%.

[0055] Example 2

[0056] (1) Hf powder, Ta powder, and C powder were mixed in a molar ratio of 0.5:0.5:0.8. The mixed powder was then ball-milled in a planetary ball mill for 1 hour. The particle size of Hf powder and Ta powder was <48μm, the particle size of C powder was <3.25μm, and the purity was ≥99%. The ball mill jar and balls were made of cemented carbide. The ball milling medium was ethanol, the rotation speed was 200rpm, and the ball-to-powder ratio was 10:1. After ball milling, the powder was removed, dried at 40℃, and sieved to obtain the mixed powder. The mixed powder was then placed in a graphite jar for high-temperature heat treatment. The process was carried out under vacuum with a vacuum degree of less than 5Pa. The temperature was raised to 1100℃ and held for 30 minutes at a heating rate of 5℃ / min. The powder was then cooled to room temperature and manually crushed to obtain carbide powder.

[0057] (2) Boron carbide and boron oxide were weighed according to a molar ratio of 3:2. The atomic ratio of boron atoms in the added boron source to carbon atoms in the carbide was 0.1:0.8. The mixture was mixed in ethanol for 0.5 h at a rotation speed of 300 rpm and a ball-to-material ratio of 10:1. After mixing, the mixture was dried at 40 °C to obtain a mixture of boron source and carbide powder. The mixture was placed in a spark plasma sintering furnace for high-temperature sintering. The sintering conditions were: vacuum degree <5 Pa, temperature rise to 2000 °C and hold for 10 min, heating rate of 200 °C / min, and sintering pressure of 60 MPa. The mixture was then cooled to room temperature and removed to obtain boron-containing carbide ceramic blocks.

[0058] (3) The macroscopic morphology of the prepared boron-containing carbide ceramic bulk is as follows: Figure 4 As shown, the microstructure of the ceramic surface is as follows: Figure 5 As shown, the ceramic surface is dense with no obvious pores, and the X-ray diffraction results of the ceramic are as follows ( Figure 6 The results showed that the boron-containing carbides were similar to TaC and HfC, exhibiting a face-centered cubic structure. ICP-OES elemental analysis revealed that the atomic ratio of Hf, Ta, C, and B in the boron-containing carbides was 0.5:0.5:0.8:0.1. The molecular formula of the boron-containing carbides is (Hf... 0.50 Ta 0.50 (C) 0.80 B 0.10 The relative density of the ceramic block is 98.1%.

[0059] Example 3

[0060] (1) Hf powder, Ta powder, and C powder were mixed in a molar ratio of 2 / 3:1 / 3:0.6. The mixed powder was then ball-milled in a planetary ball mill for 5 hours. The particle size of Hf powder and Ta powder was <48μm, the particle size of C powder was <3.25μm, and the purity was ≥99%. The ball mill jar and balls were made of cemented carbide. The ball milling medium was ethanol, the rotation speed was 100rpm, and the ball-to-powder ratio was 4:1. After ball milling, the powder was removed, dried at 40℃, and sieved to obtain the mixed powder. The mixed powder was then placed in a graphite jar for high-temperature heat treatment. The process was carried out under vacuum with a vacuum degree of less than 5Pa. The temperature was raised to 1400℃ and held for 15 minutes at a heating rate of 100℃ / min. After cooling to room temperature, the powder was removed and manually crushed to obtain carbide powder.

[0061] (2) Boron carbide and boron oxide were weighed according to a molar ratio of 3:2. The atomic ratio of boron atoms in the added boron source to carbon atoms in the carbide was 0.3:0.6. The mixture was mixed in ethanol for 24 hours at a rotation speed of 200 rpm and a ball-to-material ratio of 4:1. After mixing, the mixture was dried at 40°C to obtain a mixture of boron source and carbide powder. The mixture was placed in a spark plasma sintering furnace for high-temperature sintering under the following conditions: vacuum degree <5 Pa, temperature rise to 1600°C and hold for 30 min, heating rate of 100°C / min, and sintering pressure of 40 MPa. The mixture was then cooled to room temperature and removed to obtain boron-containing carbide ceramic blocks.

[0062] (3) The prepared boron-containing carbides have a single-phase face-centered cubic structure. ICP-OES elemental analysis showed that the atomic ratio of Hf, Ta, C, and B in the boron-containing carbides was 2 / 3:1 / 3:0.6:0.3. The molecular formula of the boron-containing carbides is (Hf... 2 / 3 Ta 1 / 3 (C) 0.60 B 0.30 The relative density of the ceramic block is 97.0%.

[0063] The antioxidant properties of the products prepared in the examples were tested, and the results are shown in Table 1. The isothermal oxidation performance analysis of the ceramic blocks was conducted in a tubular oxidation furnace. During the experiment, the temperature was 1600℃, with a temperature control accuracy of ±1℃. A mixture of N2 and O2 gas was continuously introduced during the test, with a volume ratio of N2 / O2 = 80:20 and a gas flow rate of 200 ml / min. The isothermal oxidation rate of the ceramic was evaluated using the weight gain per unit area (ΔW / A), where ΔW = W1 - W0, W1 is the mass of the ceramic after oxidation; W0 is the mass of the ceramic before oxidation (mg); and A is the surface area of ​​the ceramic (cm²). 2 Calculate the square of the weight gain per unit area of ​​the ceramic, i.e., (ΔW / A). 2 By fitting the data, a linear relationship was found between the square of the weight gain per unit area and time, namely (ΔW / A). 2 =kp ·t,k p k is the oxidation rate constant, used to determine the oxidation resistance of ceramics. p The smaller the value, the slower the ceramic oxidation and the stronger its oxidation resistance. Table 1 shows that the oxidation rate constant of the ceramic blocks prepared in the embodiments of the present invention is less than 100 mg / L in an oxidation environment of 1600℃. 2 / (cm 4 It exhibits excellent high-temperature antioxidant properties (·min).

[0064] Table 1 Antioxidant Performance Test

[0065] Relative density (%) oxidation rate constant (k p , mg 2 / (cm 4 ·min))]]> Example 1 96.7 6.0 Example 2 98.1 94.4 Example 3 97.0 50.5

[0066] Example 4

[0067] (1) Hf powder, Ta powder, and C powder were mixed in a molar ratio of 2 / 3:1 / 3:0.6. The mixed powder was then ball-milled in a planetary ball mill for 5 hours. The particle size of Hf powder and Ta powder was <48μm, the particle size of C powder was <3.25μm, and the purity was ≥99%. The ball mill jar and balls were made of cemented carbide. The ball milling medium was ethanol, the rotation speed was 50rpm, and the ball-to-material ratio was 4:1. After ball milling, the powder was removed, dried at 40℃, and sieved to obtain the mixed powder. The mixed powder was then placed in a graphite jar for high-temperature heat treatment. The process was carried out under vacuum with a vacuum degree of less than 5Pa. The temperature was raised to 1200℃ and held for 15 minutes at a heating rate of 100℃ / min. The powder was then cooled to room temperature and the artificially crushed carbide powder was removed.

[0068] (2) Boron carbide and boron oxide were weighed according to a molar ratio of 3:2. The atomic ratio of boron atoms in the added boron source to carbon atoms in the carbide was 0.3:0.6. The mixture was mixed in ethanol for 24 hours at a rotation speed of 250 rpm and a ball-to-material ratio of 5:1. After mixing, the mixture was dried at 40°C to obtain a mixture of boron source and carbide powder. The mixture was placed in a spark plasma sintering furnace for high-temperature sintering under the following conditions: vacuum degree < 5 Pa, temperature rise to 1800°C and hold for 20 min, heating rate of 100°C / min, and sintering pressure of 50 MPa. The mixture was then cooled to room temperature and removed to obtain boron-containing carbide ceramic blocks.

[0069] Example 5

[0070] (1) Hf powder, Ta powder, and C powder were mixed in a molar ratio of 2 / 3:1 / 3:0.6. The mixed powder was then ball-milled in a planetary ball mill for 5 hours. The particle size of Hf powder and Ta powder was <48μm, the particle size of C powder was <3.25μm, and the purity was ≥99%. The ball mill jar and balls were made of cemented carbide. The ball milling medium was ethanol, the rotation speed was 100rpm, and the ball-to-powder ratio was 4:1. After ball milling, the powder was removed, dried at 40℃, and sieved to obtain the mixed powder. The mixed powder was then placed in a graphite jar for high-temperature heat treatment. The process was carried out under vacuum with a vacuum degree of less than 5Pa. The temperature was raised to 1200℃ and held for 15 minutes at a heating rate of 100℃ / min. After cooling to room temperature, the powder was removed and manually crushed to obtain carbide powder.

[0071] (2) Boron carbide and boron oxide were weighed according to a molar ratio of 3:1. The atomic ratio of boron atoms in the added boron source to carbon atoms in the carbide was 0.3:0.6. The mixture was mixed in ethanol for 24 hours at a rotation speed of 250 rpm and a ball-to-material ratio of 5:1. After mixing, the mixture was dried at 40°C to obtain a mixture of boron source and carbide powder. The mixture was placed in a spark plasma sintering furnace for high-temperature sintering under the following conditions: vacuum degree < 5 Pa, temperature rise to 1800°C and hold for 20 min, heating rate of 100°C / min, and sintering pressure of 50 MPa. The mixture was then cooled to room temperature and removed to obtain boron-containing carbide ceramic blocks.

[0072] This invention discloses a boron-containing carbide ceramic for high-temperature aerobic environments and its preparation method. The method addresses the problem of how to efficiently and easily prepare bulk boron-containing carbide ceramics. First, high-temperature heat treatment is used to prepare Hf-Ta system carbides with carbon vacancies (Hf... n Ta m C x The powder provides the basis for subsequent boron atom diffusion. Then, using boron carbide and boron oxide as boron sources, boron carbide eliminates the impurity oxygen introduced by boron oxide, and (Hf) n Ta m C x After the powder is ball-milled and mixed with a boron source, it is sintered to form boron-containing carbides (Hf). n Ta m (C) x B yThis method, on the one hand, adds boron carbide and boron oxide as boron sources, allowing boron atoms to fill designed carbon vacancies without altering the crystal structure of the carbide. Simultaneously, boron carbide eliminates excess oxygen introduced by boron oxide, ultimately forming boron-containing carbides. On the other hand, the entire preparation process requires only one high-temperature treatment to prepare the powder and one high-temperature sintering to prepare the ceramic bulk. Through the dual boron sources, boron is introduced into the carbide while simultaneously removing impurity oxygen, preventing the formation of porous structures. Compared to existing technologies, this method is simpler, significantly reduces process requirements, has a simple process flow, and high preparation efficiency, making it suitable for large-scale production.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing a boride-containing ceramic for a high-temperature aerobic environment, characterized by, The method comprises the following steps: Step 1, mix Hf powder, Ta powder and carbon powder, heat treatment after ball milling, break up to get (Hf n Ta m )C x powder; Step 2, (Hf n Ta m )C x powder and boron source are ball-milled, dried after ball-milling, to obtain a mixture, and (Hf n Ta m )(C x B y ) ceramic is obtained after sintering of the mixture; wherein n / m = 1 / 1-4 / 1, 0.7≤x≤0.9, 0.05≤y≤0.3, x+y≤0.

97. The boron source comprises boron carbide and boron oxide.

2. The method of claim 1, wherein the boride-containing ceramic for a high-temperature aerobic environment is prepared by the steps of: preparing a mixture of a boride-containing ceramic powder and a binder; and molding the mixture into a predetermined shape. In step 1, the heat treatment temperature is 1100-1400℃, and the heat treatment time is ≥15 min.

3. The method of claim 1, wherein the boride-containing ceramic for a high-temperature aerobic environment is prepared by the steps of: preparing a mixture of a boride-containing ceramic powder and a binder; and molding the mixture into a predetermined shape. In step 2, the molar ratio of boron carbide to boron oxide in the boron source is 3:(2-1).

4. The method of claim 1, wherein the boride-containing ceramic for a high-temperature aerobic environment is prepared by the steps of: preparing a mixture of a boride-containing ceramic powder and a binder; and molding the mixture into a predetermined shape. In step 1, the ball milling speed is 50-200 rpm, and the ball milling time is 1-5 h.

5. The method of claim 1, wherein the boride-containing ceramic for a high-temperature aerobic environment is prepared by the steps of: preparing a mixture of a boride-containing ceramic powder and a binder; and molding the mixture into a predetermined shape. In step 2, the ball milling speed is 200-300 rpm, and the ball-to-material ratio is 4:1-10:

1.

6. The method of claim 1, wherein the boride-containing ceramic for a high-temperature aerobic environment is prepared by the steps of: preparing a mixture of a boride-containing ceramic powder and a binder; and molding the mixture into a predetermined shape. In step 2, the mixture is obtained (Hf n Ta m )(C x B y ) ceramic by sintering the mixture through spark plasma sintering, wherein the sintering temperature is 1600-2000°C, the sintering time is 10-30 min, and the pressure is 40-60 MPa.

7. A boride-containing ceramic for use in a high-temperature aerobic environment, produced by the production method according to any one of claims 1 to 6, characterized by, The boron-containing carbide ceramic has a structural formula of (Hf n Ta m )(C x B y ), and is a face-centered cubic structure in which some carbon vacancy lattices are replaced by boron. Wherein, n / m = 1 / 1-4 / 1, 0.7≤x≤0.9, 0.05≤y≤0.3, x+y≤0.

97.

8. The boride-containing ceramic of claim 7, wherein the boride-containing ceramic is used in a high-temperature aerobic environment. n / m is 3 / 1 or 4 / 1.

9. The boride-containing ceramic of claim 7, wherein the boride-containing ceramic is used in a high-temperature aerobic environment. 0.70≤x≤0.80, 0.20≤y≤0.30, x+y≤0.

90.

10. The boride-containing ceramic of claim 7, wherein the boride-containing ceramic is used in a high-temperature aerobic environment. The boride-containing ceramic is any one of (Hf 0.50 Ta 0.50 )(C 0.80 B 0.10 ), (Hf 2 / 3 Ta 1 / 3 )(C 0.60 B 0.30 ), or (Hf 0.75 Ta 0.25 )(C 0.88 B 0.09 ).

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