Ultrahigh-temperature material single-phase HfxTa (1-x) C powder and preparation method thereof

Abstract

The invention discloses ultrahigh-temperature material single-phase Hf < x > Ta < 1-x > C powder and a preparation method thereof. The preparation method comprises the following steps: carrying out wet ball milling on Hf < C > powder and TaC powder, heating, stirring, grinding and sieving to obtain mixed powder; granulating the mixed powder, drying and sieving to obtain agglomerated powder; carrying out high-temperature Joule heat treatment on the agglomerated powder in an environment with a vacuum degree of less than 0.093 MPa by adopting a multi-time heating-cooling circulation Joule heat technology, so that TaC and HfC are mutually diffused in the high-temperature Joule heat treatment process and are completely subjected to solid solution to obtain single-phase Hf < x > Ta < 1-x > C powder with good uniformity; the preparation method disclosed by the invention has the characteristics of simple equipment operation, controllable reaction process, short reaction time and low energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-high temperature materials, and particularly relates to a single-phase Hf x Ta 1-x C powder and a preparation method thereof. Background Art

[0002] Hf x Ta 1-x C is a ceramic material with excellent ultra-high temperature performance and mechanical properties, and has broad application prospects in the fields of aerospace, nuclear industry, electronic devices, and composite materials. At present, the preparation technology of Hf x Ta 1-x C ceramic blocks has been relatively mature. For example, the Chinese patent document with the application number CN201810570475.2 uses atmospheric pressure solid-phase sintering to prepare dense Ta x Hf 1-x C ceramic blocks by holding at 2000°C for 1 h. The Chinese patent document with the application number CN201910196449.2 uses non-contact flash sintering technology to prepare HfTaC2 ceramic blocks with stable performance in a short time and high efficiency. However, the research on the preparation technology of Hf x Ta 1-x C powder is less, and the related process development lags behind. However, the demand for Hf x Ta 1-x C powder in practical applications is much higher than that of blocks, because it has better formability, processability, and adaptability, and plays an important role especially in the fields of coating manufacturing, composite material reinforcement, and additive manufacturing. Therefore, how to develop an efficient, controllable, and economical Hf x Ta 1-x C powder preparation technology to meet its wide industrial application needs has become a technical problem that urgently needs to be solved at present.

[0003] Existing preparation methods for single-phase Hf x Ta 1-x C powder. For example, the patent document with the application number CN201510371267.6 discloses a method for preparing Ta-Hf-C ternary continuous single-phase solid solution ceramic powder by combining solvothermal method with high-temperature calcination, but it needs to react at least at 1600°C for 1 h to be completely dissolved, and the reaction time for obtaining the precursor is long, and it is easy to have incomplete reaction resulting in residue of raw materials or intermediate products, and the product quality is low. The patent document with the application number CN201811045318.6 discloses a synthesis method of Ta4HfC5 ceramic powder, using HfCl4, TaCl5, and phenolic resin as raw materials, dissolving through acetylacetone and n-butanol, and precipitating the precursor by titrating with ammonia water, but it needs to react at least at 1400°C for 1 h to be completely dissolved, and the particle size uniformity of the powder cannot be controlled, and the powder purity is easily affected. Summary of the Invention

[0004] In order to overcome the above-mentioned drawbacks in the prior art, the object of the present invention is to provide a single-phase Hf x Ta 1-x TaC powder and its preparation method. Through multiple heating-cooling cycle Joule heat technology for rapid reaction, mutual diffusion occurs between TaC and HfC during high-temperature Joule heat treatment, and complete solid solution is achieved, successfully preparing a single-phase Hf x Ta 1- x TaC powder with good uniformity. The preparation method of the present invention is simple, highly operable, and has low energy consumption, making up for the deficiencies in the existing preparation process of Hf x Ta 1-x TaC powder, suitable for large-scale production, providing an excellent solution for the industrial preparation of high-performance materials, and meeting the growing demand for single-phase Hf x Ta 1-x TaC powder in fields such as aerospace and nuclear industry.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A preparation method of a single-phase Hf x Ta 1-x TaC powder, comprising the following steps:

[0007] Step 1: Wet ball-mill the HfC powder and TaC powder; by mass ratio, the HfC powder: TaC powder = 1:9 to 9:1;

[0008] Step 2: Heat and stir the ball-milled slurry, and then grind and screen it to obtain a mixed powder;

[0009] Step 3: Granulate the mixed powder, dry and screen it to obtain an agglomerated powder;

[0010] Step 4: Perform high-temperature Joule heat treatment on the agglomerated powder by using multiple heating-cooling cycle Joule heat technology to obtain a single-phase Hf x Ta 1-x TaC powder.

[0011] In Step 1, the particle size of the HfC powder is 1 to 3 μm, and the purity is ≥ 99.9%; the particle size of the TaC powder is 1 to 3 μm, and the purity is ≥ 99.9%.

[0012] In Step 1, the ball-milling speed is 300 to 450 r / min, and the ball-milling time is 7 to 11 h.

[0013] In Step 2, the stirring speed is 200 - 400 r / min, the heating temperature is 100 - 180 °C, and the heating time is 3 - 6 h; the grinding time is 1 - 3 h.

[0014] In Step 3, the drying temperature is 90 - 130 °C.

[0015] In Step 3, the particle size of the agglomerated powder is 100 - 200 mesh.

[0016] In Step 4, the process of high-temperature Joule heat treatment is as follows: in an environment with a vacuum degree less than 0.093 MPa, use a Joule heating furnace to rapidly heat the agglomerated powder to at least 1900 °C and hold for 90 - 300 s at a current of not less than 300 A, then naturally cool to room temperature, and perform the heating-cooling cycle 3 - 10 times to obtain single-phase Hf x Ta 1-x C powder.

[0017] In Step 4, the heating rate is at least 1900 °C / s.

[0018] The present invention also provides a single-phase Hf x Ta 1-x C powder prepared by the preparation method of the ultra-high temperature material single-phase Hf x Ta 1-x C powder, and the chemical formula of the single-phase Hf x Ta 1-x C powder is Hf x Ta 1-x C, where x is 0.1 - 0.9.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The present invention uses the multi-time heating-cooling cycle Joule heat technology to perform high-temperature Joule heat treatment on the agglomerated powder of TaC and HfC. Through the Joule effect, electrical energy is rapidly converted into heat energy to directly heat the reactants, reducing heat loss, with high energy conversion efficiency. It can achieve rapid and uniform heating, complete the reaction in an extremely short time, reduce energy consumption, and reduce production costs; by adjusting the proportion of hafnium in the metal sites, continuous component regulation from TaC to HfC is achieved, forming a single-phase Hf x Ta 1-x C powder with good uniformity; and the entire process can monitor and adjust variables such as temperature, current, and reaction time in real time, making the entire reaction process more controllable and adjustable. This high degree of controllability enables the reaction to proceed under the most suitable conditions, optimizing the synthesis process of Hf x Ta 1-x C powder. Compared with the existing Hf x Ta 1-xC powder preparation technology, the joule heating equipment is easy to operate, can be started and stopped quickly, has strong adaptability and flexibility, and is suitable for large-scale industrial production of single-phase Hf with good uniformity x Ta 1-x C powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 XRD patterns of the Hf x Ta 1-x C powders prepared in Examples 1-7 and Comparative Examples 1-2.

[0022] Figure 2 SEM images and EDS elemental distribution maps of the single-phase Hf 0.5 Ta 0.5 C powder prepared in Example 4, where Figure 2 (a) is the SEM image, Figure 2 (b) is the Hf elemental distribution map, Figure 2 (c) is the Ta elemental distribution map.

[0023] Figure 3 TEM images of the single-phase Hf 0.5 Ta 0.5 C powder prepared in Example 4, where Figure 3 (a) is the HAADF image, Figure 3 (b) and Figure 3 (c) are both HRTEM images, Figure 3 (d) is the selected area electron diffraction. DETAILED DESCRIPTION OF THE INVENTION

[0024] The technical solution of the present invention will be further introduced below in conjunction with specific examples and drawings.

[0025] A single-phase Hf of a ultra-high temperature material x Ta 1-x C powder, with the chemical formula Hf x Ta 1-x C, where x is the proportion of hafnium in the metal site, and continuous composition regulation from TaC to HfC can be achieved by adjusting x to form a single-phase Hf x Ta 1-x C powder; x is 0.1 to 0.9.

[0026] A method for preparing a single-phase Hf of a ultra-high temperature material x Ta 1-x C powder, comprising the following steps:

[0027] Step 1: Wet ball mill the HfC powder and TaC powder; by mass ratio, the HfC powder:TaC powder = 1:9 to 9:1; the particle size of the HfC powder is 1 - 3 μm, the purity ≥ 99.9%, the particle size of the TaC powder is 1 - 3 μm, the purity ≥ 99.9%; the ball milling speed is 300 - 450 r / min, the ball milling time is 7 - 11 h, the ball milling medium is anhydrous ethanol, the ball milling beads are zirconia balls, and the ball-to-material ratio is 3:1;

[0028] Step 2: Use a magnetic stirrer to heat and stir the milled slurry, the stirring speed is 200 - 400 r / min, the heating temperature is 100 - 180 °C, the heating time is 3 - 6 h, to remove the liquid phase medium and evaporate the slurry dry to avoid solvent residue affecting the performance, obtaining a dry, stable and suitable product for subsequent applications, then grind for 1 - 3 h, and obtain a mixed powder with a particle size of about 200 mesh after sieving;

[0029] Step 3: Granulate the mixed powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol, dry the granulated powder at 90 - 130 °C, and obtain an agglomerated powder with a particle size of 100 - 200 mesh after sieving;

[0030] Step 4: Load the agglomerated powder from Step 3 into a graphite sample tube, place it together in a Joule heating furnace, in an environment with a vacuum degree less than 0.093 MPa, the current is not less than 300 A, perform high-temperature Joule heat treatment on the agglomerated powder, and obtain single-phase Hf x Ta 1-x C powder; the high-temperature Joule heat treatment process is: rapidly heat up to at least 1900 °C at a heating rate of at least 1900 °C / s and hold for 90 - 300 s, then naturally cool to room temperature, and perform the heating-cooling cycle 3 - 10 times. Through the high-temperature and multiple heating-cooling cycle Joule heat technology, thermal activation energy can be repeatedly provided to promote atomic diffusion, gradually break local composition segregation or metastable phases, at high temperatures, configurational entropy dominates, and the phase separation tendency is gradually inhibited through the principle of entropy increase during the cycle process, which is beneficial to solid solution.

[0031] Example 1

[0032] A preparation method of single-phase Hf 0.1 Ta 0.9 C powder, comprising the following steps:

[0033] Step 1: Wet ball mill the raw material HfC powder and TaC powder at a mass ratio of 1:9 at 450 r / min for 7 h; the particle size of the HfC powder is 1 - 3 μm, the purity ≥ 99.9%, the particle size of the TaC powder is 1 - 3 μm, the purity ≥ 99.9%;

[0034] Step 2: Use a magnetic stirrer to heat and stir the ball-milled slurry for 3 h, with a stirring speed of 400 r / min and a heating temperature of 180 °C, then grind for 1 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0035] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 90 °C and sieved to obtain an agglomerated powder with a particle size of 100 - 200 mesh;

[0036] Step 4: Load the dried agglomerated powder into a graphite sample tube, place it together in a Joule heating furnace. In an environment with a vacuum degree of 0.093 MPa, set the current to 320 A, and use Joule heat to rapidly heat the agglomerated powder to 2000 °C at a heating rate of 2000 °C / s and hold for 300 s, then naturally cool to room temperature. Perform the heating-cooling cycle 3 times to obtain single-phase Hf 0.1 Ta 0.9 C powder.

[0037] Example 2

[0038] A preparation method of single-phase Hf 0.2 Ta 0.8 C powder, comprising the following steps:

[0039] Step 1: Wet ball-mill the raw material HfC powder and TaC powder at a mass ratio of 1:4 at 300 r / min for 7 h; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%;

[0040] Step 2: Use a magnetic stirrer to heat and stir the ball-milled slurry for 4 h, with a stirring speed of 350 r / min and a heating temperature of 150 °C, then grind for 2 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0041] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 90 °C and sieved to obtain an agglomerated powder with a particle size of 100 - 200 mesh;

[0042] Step 4: Load the dried agglomerated powder into a graphite sample tube, place it together in a Joule heating furnace. In an environment with a vacuum degree of 0.093 MPa, set the current to 300 A, and use Joule heat to rapidly heat the agglomerated powder to 1900 °C at a heating rate of 1900 °C / s and hold for 130 s, then naturally cool to room temperature. Perform the heating-cooling cycle 7 times to obtain single-phase Hf 0.2 Ta 0.8 C powder.

[0043] Example 3

[0044] A preparation method of single-phase Hf 0.5 Ta 0.5 C powder, comprising the following steps:

[0045] Step 1: Wet ball-mill the raw material HfC powder and TaC powder at a mass ratio of 1:1 for 9 h at 300 r / min; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%;

[0046] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120°C, then grind for 2 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0047] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol, dry the granulated powder at 100°C, and obtain agglomerated powder with a particle size of 100 - 200 mesh after sieving;

[0048] Step 4: Load the dried agglomerated powder into a graphite sample tube, place it together in a Joule heating furnace, in an environment with a vacuum degree of 0.093 MPa, set the current to 300 A, use Joule heat to rapidly heat the agglomerated powder to 1900°C at a heating rate of 1900°C / s and hold for 300 s, then naturally cool to room temperature, and perform the heating-cooling cycle 3 times to obtain single-phase Hf 0.5 Ta 0.5 C powder.

[0049] Example 4

[0050] A preparation method of single-phase Hf 0.5 Ta 0.5 C powder, comprising the following steps:

[0051] Step 1: Wet ball-mill the raw material HfC powder and TaC powder at a mass ratio of 1:1 for 9 h at 300 r / min; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%;

[0052] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120°C, then grind for 2 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0053] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 100 °C and sieved to obtain an agglomerated powder with a particle size of 100 - 200 mesh.

[0054] Step 4: Load the dried agglomerated powder into a graphite sample tube and place it together in a Joule heating furnace. In an environment with a vacuum degree of 0.093 MPa, the current is set to 300 A. Using Joule heat, the agglomerated powder is rapidly heated to 1900 °C at a heating rate of 1900 °C / s and held for 180 s, then naturally cooled to room temperature. The heating - cooling cycle is carried out 5 times to obtain single - phase Hf 0.5 Ta 0.5 C powder.

[0055] Example 5

[0056] A preparation method of single - phase Hf 0.67 Ta 0.33 C powder for ultra - high temperature materials, comprising the following steps:

[0057] Step 1: Wet - ball - mill the raw material HfC powder and TaC powder at a mass ratio of 2:1 for 10 h at 400 r / min; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%.

[0058] Step 2: Use a magnetic pole stirrer to heat - stir the ball - milled slurry for 6 h, with a stirring speed of 200 r / min and a heating temperature of 100 °C, then grind for 2 h and sieve to obtain a powder with a particle size of about 200 mesh.

[0059] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 120 °C and sieved to obtain an agglomerated powder with a particle size of 100 - 200 mesh.

[0060] Step 4: Load the dried agglomerated powder into a graphite sample tube and place it together in a Joule heating furnace. In an environment with a vacuum degree of 0.093 MPa, the current is set to 300 A. Using Joule heat, the agglomerated powder is rapidly heated to 1900 °C at a heating rate of 1900 °C / s and held for 90 s, then naturally cooled to room temperature. The heating - cooling cycle is carried out 10 times to obtain single - phase Hf 0.67 Ta 0.33 C powder.

[0061] Example 6

[0062] A preparation method of single - phase Hf 0.8 Ta 0.2 C powder for ultra - high temperature materials, comprising the following steps:

[0063] Step 1: Wet ball mill the raw material HfC powder and TaC powder at a mass ratio of 4:1 for 11 h at 300 r / min; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%;

[0064] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120°C, then grind for 2 h, and obtain a powder with a particle size of about 200 mesh after sieving;

[0065] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol, dry the granulated powder at 130°C, and obtain an agglomerated powder with a particle size of 100 - 200 mesh after sieving;

[0066] Step 4: Load the dried agglomerated powder into a graphite sample tube, place it together in a Joule heating furnace, in an environment with a vacuum degree of 0.093 MPa, set the current to 300 A, use Joule heat to rapidly heat the agglomerated powder to 1900°C at a heating rate of 1900°C / s and hold for 300 s, then naturally cool to room temperature, and perform the heating-cooling cycle 3 times to obtain single-phase Hf 0.8 Ta 0.2 C powder.

[0067] Example 7

[0068] A method for preparing single-phase Hf 0.9 Ta 0.1 C powder, comprising the following steps:

[0069] Step 1: Wet ball mill the raw material HfC powder and TaC powder at a mass ratio of 9:1 for 11 h at 300 r / min; the particle size of the HfC powder is 1 - 3 μm and the purity is ≥99.9%, and the particle size of the TaC powder is 1 - 3 μm and the purity is ≥99.9%;

[0070] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120°C, then grind for 3 h, and obtain a powder with a particle size of about 200 mesh after sieving;

[0071] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol, dry the granulated powder at 130°C, and obtain an agglomerated powder with a particle size of 100 - 200 mesh after sieving;

[0072] Step 4: Load the dried agglomerated powder into a graphite sample tube, and place it together in a Joule heating furnace. Under an environment with a vacuum degree of 0.093 MPa, set the current to 320 A. Use Joule heat to rapidly heat the agglomerated powder to 2000 °C at a heating rate of 2000 °C / s, hold for 300 s, and then naturally cool to room temperature. Perform the heating-cooling cycle 3 times to obtain single-phase Hf 0.9 Ta 0.1 C powder.

[0073] Comparative Example 1

[0074] A preparation method of single-phase Hf-Ta-C powder for ultra-high temperature materials, comprising the following steps:

[0075] Step 1: Mix and ball-mill the raw material HfC powder and TaC powder at a mass ratio of 1:1 for 9 h at 300 r / min;

[0076] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120 °C, then grind for 2 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0077] Step 3: Granulate the powder with a particle size of about 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 100 °C and sieved to obtain agglomerated powder with a particle size of 100-200 mesh;

[0078] Step 4: Load the dried agglomerated powder into a graphite sample tube, and place it together in a Joule heating furnace. Under an environment with a vacuum degree of 0.093 MPa, set the current to 300 A. Use Joule heat to rapidly heat the agglomerated powder to 1900 °C at a heating rate of 1900 °C / s, hold for 450 s, and then naturally cool to room temperature. Perform the heating-cooling cycle 2 times to obtain incompletely solid-solved Hf-Ta-C powder.

[0079] Comparative Example 2

[0080] A preparation method of single-phase Hf-Ta-C powder for ultra-high temperature materials, comprising the following steps:

[0081] Step 1: Mix and ball-mill the raw material HfC powder and TaC powder at a mass ratio of 1:1 for 9 h at 300 r / min;

[0082] Step 2: Use a magnetic pole stirrer to heat and stir the ball-milled slurry for 5 h, with a stirring speed of 300 r / min and a heating temperature of 120 °C, then grind for 2 h, and obtain powder with a particle size of about 200 mesh after sieving;

[0083] Step 3: Granulate the powder with a particle size of approximately 200 mesh using a 4% aqueous solution of polyvinyl alcohol. The granulated powder is dried at 100 °C and then sieved to obtain an agglomerated powder with a particle size of 100 - 200 mesh.

[0084] Step 4: Load the dried agglomerated powder into a graphite sample tube and place it together in a Joule heating furnace. In an environment with a vacuum degree of 0.093 MPa, the current is set to 290 A. Using Joule heat, the agglomerated powder is rapidly heated to 1850 °C at a heating rate of 1850 °C / s and held at this temperature for 300 s, and then naturally cooled to room temperature. The heating-cooling cycle is repeated 3 times to obtain an incompletely solid-solved Hf-Ta-C powder.

[0085] In more embodiments of the present invention, the mass ratios of HfC powder and TaC powder are respectively selected as 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 2:3, 2:5, 2:7, 2:9, 3:1, 3:2, 3:4, 3:5, 3:7, 3:8, 4:1, 4:3, 4:5, 4:7, 4:9, 5:1, 5:2, 5:3, 5:4, 5:6, 5:7, 5:8, 5:9, 6:1, 6:5, 6:7, 7:1, 7:2, 7:3, 7:4, 7:5, 7:6, 7:8, 7:9, 8:1, 8:3, 8:5, 8:7, 9:1. The results prove that single-phase Hf x Ta 1-x C powder can be prepared in all cases.

[0086] Figure 1 are the XRD patterns of the Hf x Ta 1-x C powders prepared in Examples 1 - 7 and Comparative Examples 1 - 2. As can be seen from Figure 1 this, the diffraction peaks of all specimens in the examples show high-crystallinity single-phase Hf x Ta 1-x C diffraction characteristics, and there is no second phase. On a macroscopic scale, it proves the single-phase diffraction characteristics of the material, indicating that TaC and HfC have undergone mutual diffusion during high-temperature heat treatment, causing their diffraction peaks to approach each other and finally merge; in the comparative examples, two sets of independent diffraction peaks of HfC and TaC can still be observed, but they also start to gradually approach and tend to merge, which indicates that the solid solution reaction has started but has not been completely solid-solved.

[0087] Figure 2 and Table 1 are the SEM images and the results of surface EDS analysis of the elemental contents of the single-phase Hf 0.5 Ta 0.5 C powder sample prepared in Example 4; the single-phase Hf 0.5 Ta 0.5No obvious large cracks were observed in the C powder, and its internal structure was relatively loose; in single-phase Hf 0.5 Ta 0.5 The distributions of Hf and Ta elements on the surface of the C powder were relatively uniform, without obvious segregation or enrichment phenomena, and the atomic ratio of Hf and Ta was close to 1:1.

[0088] Table 1 Results of elemental content analysis on the surface of the sample (at%)

[0089]

[0090] Figure 3 And Table 2 are the TEM images and the results of elemental content analysis on the surface of the single-phase Hf 0.5 Ta 0.5 C powder sample prepared in Example 4; as can be seen from Figure 3 (a), the chemical composition of the single-phase Hf 0.5 Ta 0.5 C powder prepared in Example 4 was highly uniform on the microscale, without elemental segregation and agglomeration phenomena; point scanning showed that the atomic ratio of Hf and Ta was close to 1:1, which was consistent with the SEM results. As can be seen from Figure 3 (b) and (c), the lattice fringe spacing of the (200) crystal plane of the single-phase Hf 0.5 Ta 0.5 C solid solution prepared in Example 4 was 0.2286 nm, which was basically consistent with the theoretical calculated value (0.2272 nm); Figure 3 (d) corresponded to the face-centered cubic structure along the zone axis, thus further confirming the formation of the Hf 0.5 Ta 0.5 C single-phase solid solution.

[0091] Table 2 Results of elemental content analysis on the surface of the sample (at%)

[0092]

Claims

1. A method for preparing single-phase Hf x Ta 1-x C powder, characterized in that It includes the following steps: Step 1: Wet ball-mill the HfC powder and TaC powder; by mass ratio, the HfC powder: TaC powder = 1:9 to 9:1; Step 2: Heat and stir the ball-milled slurry, and then obtain the mixed powder after grinding and sieving; Step 3: Granulate the mixed powder, and obtain the agglomerated powder after drying and sieving; Step 4: Perform high-temperature Joule heat treatment on the agglomerated powder using a multi-step heating-cooling cycle Joule heat technique to obtain single-phase Hf x Ta 1-x C powder.

2. A method for preparing single-phase Hf x Ta 1-x C powder according to claim 1, characterized in that: In Step 1, the particle size of the HfC powder is 1 to 3 μm, and the purity is ≥99.9%; the particle size of the TaC powder is 1 to 3 μm, and the purity is ≥99.9%.

3. A method for preparing single-phase Hf x Ta 1-x C powder according to claim 1, characterized in that: In Step 1, the ball-milling rotation speed is 300 to 450 r / min, and the ball-milling time is 7 to 11 h.

4. A preparation method of single-phase Hf x Ta 1-x TaC powder according to claim 1, characterized in that: In Step 2, the stirring rotation speed is 200 to 400 r / min, the heating temperature is 100 to 180 °C, and the heating time is 3 to 6 h; the grinding time is 1 to 3 h.

5. A preparation method of single-phase Hf x Ta 1-x C powder according to claim 1, characterized in that: In Step 3, the drying temperature is 90 to 130 °C.

6. A preparation method of single-phase Hf x Ta 1-x TaC powder according to Claim 1, characterized in that: In Step 3, the particle size of the agglomerated powder is 100 to 200 mesh.

7. A preparation method of single-phase Hf x Ta 1-x C powder according to claim 1, characterized in that: In Step 4, the process of the high-temperature Joule heat treatment is as follows: in an environment with a vacuum degree less than 0.093 MPa, use a Joule heating furnace to rapidly heat the agglomerated powder to at least 1900 °C and hold for 90 - 300 s at a current of not less than 300 A, then naturally cool to room temperature, and perform the heating-cooling cycle 3 - 10 times to obtain single-phase Hf x Ta 1-x C powder.

8. A method for preparing single-phase Hf x Ta 1-x C powder according to claim 7, characterized in that: In Step 4, the heating rate is at least 1900 °C / s.

9. A single-phase Hf x Ta 1-x C powder prepared by the preparation method of claim 1-8, x Ta 1-x C powder, characterized in that: The single-phase Hf x Ta 1-x The chemical formula of the Ta x C powder is Hf 1-x Ta C, where x is 0.1 to 0.9.

Images