CN110407213A - A kind of (Ta, Nb, Ti, V)C high-entropy carbide nano-powder and preparation method thereof - Google Patents

Abstract

The invention discloses a (Ta, Nb, Ti, V)C high-entropy carbide nano-powder and a preparation method thereof. The preparation method includes the following steps: (1) grinding and mixing Ta powder, Nb powder, Ti powder, V powder, C powder and KCl; (2) sintering the mixed powder at high temperature, and introducing Ar gas during the sintering process for protection, After the sintering is completed, it is cooled to room temperature; (3) the sintered mixed powder is washed with deionized water, filtered and dried to finally obtain the (Ta, Nb, Ti, V)C high-entropy carbide nano-powder. The method of the invention not only adopts low price of raw materials, low synthesis temperature, and low equipment requirements, but also the synthesized (Ta, Nb, Ti, V)C high-entropy carbide nano-powder has a small grain size (average grain size 80–90 nm), high purity and uniform composition, these advantages make this method have the potential to develop into large-scale industrial production.

Description

A kind of (Ta, Nb, Ti, V)C high-entropy carbide nano-powder and preparation method thereof

technical field

The invention belongs to the technical field of high-entropy compounds, in particular to a (Ta, Nb, Ti, V)C high-entropy carbide nano-powder and a preparation method thereof.

Background technique

The concept of high-entropy material was first proposed by Professor Ye Junwei from Tsinghua University, Taiwan, China in 2004, and defined it as element species ≥ 4, no dominant element, and the content of each element is between 5% and 35%. Up to now, the research on high-entropy materials by domestic and foreign researchers is mainly concentrated in the field of alloys, and there is less research in the field of ceramics. High-entropy ceramic materials are a new type of ceramic materials that have appeared in recent years. Since the concept of high-entropy oxide ceramic materials was first reported in 2015, high-entropy ceramic materials have become a research hotspot in recent years. , borides, nitrides and carbide ceramic materials have been reported. Among them, high-entropy carbide ceramic materials have attracted extensive attention of domestic and foreign researchers due to their extremely high melting point, low thermal conductivity, excellent mechanical properties, and good high-temperature physical and chemical stability. However, the currently prepared high-entropy carbide ceramic materials generally have some problems such as large grain size, high porosity, and uneven element composition. The synthesis of high-purity, ultra-fine, high-entropy carbide ceramic powders plays a crucial role in solving the above problems. However, there are few reports on the synthesis of high-purity, ultra-fine, high-entropy carbide ceramic powders at home and abroad.

Literature: "Zhou J, Zhang J, Zhang F, et al. High-entropy carbide: A novel class of multicomponent ceramics. Ceramics International, 2018, 44(17): 22014~ 22018." A method of preparing (Hf, Ta, Ti, Zr, Nb)C high-entropy carbide powders at 2000 ℃ by using SPS sintering technology at 2000℃. This method not only has expensive raw materials, high preparation temperature (2000°C), and high equipment requirements, but also the synthesized (Hf, Ta, Ti, Zr, Nb)C high-entropy carbide powder has large grain size (micron scale), high composition Inhomogeneity and low purity, these shortcomings seriously limit the promotion and application of this method.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings and deficiencies of the prior art, the purpose of the present invention is to provide a (Ta, Nb, Ti, V)C high-entropy carbide nano-powder and a preparation method thereof. In the method, Ta powder, Nb powder, Ti powder, V powder and C powder are used as raw materials, KCl is used as molten salt medium, and a kind of (Ta, Nb, Ti, V) is prepared by direct reaction of raw materials in molten salt at low temperature )C high-entropy carbide nano-powder, the method not only has low raw material price, low synthesis temperature, and low equipment requirements, but also the prepared (Ta, Nb, Ti, V)C high-entropy carbide nano-powder has uniform composition and high purity. And the grain size is small (average grain size is 80 ~ 90nm).

The object of the present invention is achieved by at least one of the following technical solutions.

A preparation method of (Ta, Nb, Ti, V)C high-entropy carbide nano-powder, comprising the following steps:

(1) Grind and mix Ta powder, Nb powder, Ti powder, V powder, C powder and KCl;

(2) The mixed powder is sintered at high temperature, protected by Ar gas during the sintering process, and cooled to room temperature after the sintering is completed;

(3) The sintered mixed powder is washed with deionized water, filtered and dried to finally obtain the (Ta, Nb, Ti, V)C high-entropy carbide nano-powder.

Further, in the step (1), the particle size of Ta powder, Nb powder, Ti powder, and V powder are all 1~3 μm, and the purity is all ≥99.5%, and the particle size of C powder is 0.7~0.9 μm, and the purity is ≥99.5%. 99.9%.

Further, in the step (1), the molar ratio of Ta powder, Nb powder, Ti powder, and V powder is 1:1:1:1, and the total amount of Ta powder, Nb powder, Ti powder, and V powder is the same as C. The molar ratio of powder is 1:1.0~1:1.2; the quality of KCl salt is 10~20 times of the total mass of Ta powder, Nb powder, Ti powder, V powder and C powder.

Further, in the step (1), the manual grinding time is 10-30 min.

Further, in the step (2), the heating rate during the sintering process is 5-10°C/min, the sintering temperature is 1200-1300°C, the holding time is 30-90 min, and the flow rate of the Ar gas is 300-400°C. sccm.

Further, in the step (3), the temperature of the deionized water is 80-100°C.

Further, in the step (3), the drying temperature is 40-80° C., and the drying time is 2-5 h.

The (Ta, Nb, Ti, V)C high-entropy carbide nano-powder prepared by the above preparation method.

In the preparation method, Ta powder, Nb powder, Ti powder, V powder and C powder are used as raw materials, KCl is used as molten salt medium, they are uniformly mixed in a certain proportion, and then heat treated at 1200-1300 ℃ for 30-90 min , (Ta, Nb, Ti, V)C high-entropy carbide nano-powders were prepared by direct reaction of raw materials in molten salt, and then washed with hot deionized water to remove KCl salts, and finally (Ta, Nb, Ti, V)C high-entropy carbide nanopowder.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The raw materials used in the preparation method of the present invention are low in price, low in synthesis temperature, low in equipment requirements, and low in production cost, which is beneficial to large-scale industrial production;

(2) The (Ta, Nb, Ti, V)C high-entropy carbide nano-powder synthesized by the preparation method of the present invention has small grain size (average grain size is 80-90 nm), high purity and uniform composition, These advantages give the method the potential to develop into large-scale industrial production.

Description of drawings

1 is the XRD pattern of the (Ta, Nb, Ti, V)C high-entropy nano-powder synthesized in Example 2;

2 is an SEM image and an EDS energy spectrum element distribution diagram of the (Ta, Nb, Ti, V)C high-entropy nano-powder synthesized in Example 2.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings, but the protection scope and implementation manner of the present invention are not limited thereto.

In the specific embodiment of the present invention, the particle diameters of the Ta powder, Nb powder, Ti powder, and V powder used are all 1 to 3 μm, and the purity is all ≥99.5%, and the particle diameter of the C powder is 0.7 to 0.9 μm, and the purity is ≥99.9%. ; The purity of the KCl salt used is of analytical grade.

Example 1

(1) Weigh out 0.45 g of Ta powder, 0.23 g of Nb powder, 0.12 g of Ti powder, 0.13 g of V powder, 0.12 g of C powder, and 10.50 g of KCl salt, respectively, and place them in an agate mortar and grind them manually. Mix the powder evenly for 10 min, and transfer the above powder to the corundum ark;

(2) Put the ark into the atmosphere furnace, vacuumize the atmosphere furnace, make the vacuum degree reach ^10-1 MPa after evacuating for 10 minutes, keep the vacuum for 10 minutes, and observe whether the indication of the vacuum gauge changes, if there is no change, Indicates that the system is well sealed, and this process is repeated three times. Ar gas was introduced to normal pressure, and then the furnace temperature was raised from room temperature to 1200 °C at a heating rate of 5 °C/min, and kept for 30 minutes; then the power was turned off and cooled to room temperature naturally. The flow is kept at 300 sccm;

(3) The obtained mixture was washed in deionized water at 80 °C, filtered, and dried in an oven at 40 °C for 2 h to obtain the target product. The (Ta, Nb, Ti, V)C high-entropy carbide powders synthesized under these conditions are pure phase, with a granular morphology and an average grain size of about 85 nm.

Example 2

(1) Weigh out 0.45 g of Ta powder, 0.23 g of Nb powder, 0.12 g of Ti powder, 0.13 g of V powder, 0.13 g of C powder, and 15.90 g of KCl salt, respectively, and place them in an agate mortar and grind them manually. Mix the powder evenly for 20 min, and transfer the above powder to the corundum ark;

(2) Put the ark into the atmosphere furnace, vacuumize the atmosphere furnace, make the vacuum degree reach ^10-1 MPa after evacuating for 10 minutes, keep the vacuum for 10 minutes, and observe whether the indication of the vacuum gauge changes, if there is no change, Indicates that the system is well sealed, and this process is repeated three times. Ar gas was introduced to normal pressure, and then the furnace temperature was raised from room temperature to 1250 °C at a heating rate of 8 °C/min, and kept for 60 minutes; then the power was turned off and cooled to room temperature naturally. The flow is kept at 350 sccm;

(3) The obtained mixture was washed in deionized water at 90 °C, filtered, and dried in an oven at 60 °C for 4 h to obtain the target product.

Fig. 1 is the XRD pattern of the (Ta, Nb, Ti, V)C high-entropy carbide powder prepared in this example, the pattern shows that the synthesized powder is composed of a single (Ta _0.25 Nb _0.25 Ti _0.25 V _0.25 ) C-phase composition, no other impurity phase was found, so the high-entropy carbide nano-powder prepared by this method is of high purity. 2 is an SEM image and an EDS energy spectrum element distribution diagram of the (Ta, Nb, Ti, V)C high-entropy carbide powder synthesized in the present embodiment. It can be seen from (a) in Figure 2 that the (Ta, Nb, Ti, V)C high-entropy carbide powders synthesized in this example are nano-powders, and their average grain size is about 80 nm. It can be seen from the energy spectrum analysis ((b)-(e) in Figure 2) that the four metal elements Ta, Nb, Ti, and V are uniformly distributed in the synthesized powder.

Example 3

(1) Weigh out 0.45 g of Ta powder, 0.23 g of Nb powder, 0.12 g of Ti powder, 0.13 g of V powder, 0.14 g of C powder, and 25.00 g of KCl salt, respectively, and place them in an agate mortar and grind them manually. Mix the powder evenly for 30 min, and transfer the above powder to the corundum ark;

(2) Put the ark into the atmosphere furnace, vacuumize the atmosphere furnace, make the vacuum degree reach ^10-1 MPa after evacuating for 10 minutes, keep the vacuum for 10 minutes, and observe whether the indication of the vacuum gauge changes, if there is no change, Indicates that the system is well sealed, and this process is repeated three times. Ar gas was introduced to normal pressure, and then the furnace temperature was raised from room temperature to 1300 °C at a heating rate of 10 °C/min, and kept for 90 minutes; then the power was turned off and cooled to room temperature naturally. The flow is kept at 400 sccm;

(3) The obtained mixture was washed in deionized water at 100 °C, filtered, and dried in an oven at 80 °C for 5 h to obtain the target product. The (Ta, Nb, Ti, V)C high-entropy carbide powders synthesized under these conditions are pure phase, with nano-particle morphology and an average grain size of about 90 nm.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (8)

1. the preparation method of one kind (Ta, Nb, Ti, V) C high entropy carbide nano powder, which is characterized in that including walking as follows It is rapid:

(1) by Ta powder, Nb powder, Ti powder, V powder, C powder and KCl ground and mixed；

(2) by mixed powder high temperature sintering, it is passed through Ar gas shielded in sintering process, is cooled to room temperature after the completion of sintering；

(3) mixed powder through oversintering is through deionized water washing, filtering and dry, finally obtain it is described (Ta, Nb, Ti, V) C high entropy carbide nano powder.

2. preparation method according to claim 1, which is characterized in that in the step (1), Ta powder, Nb powder, Ti powder, V powder Partial size be 1 ~ 3 μm, purity >=partial size of 99.5%, C powder is 0.7 ~ 0.9 μm, purity >=99.9%.

3. preparation method according to claim 1, which is characterized in that in the step (1), Ta powder, Nb powder, Ti powder, V powder Molar ratio be 1:1:1:1, Ta powder, Nb powder, Ti powder, V powder total amount and C powder molar ratio be 1:1.0 ~ 1:1.2；KCl salt Quality is 10 ~ 20 times of Ta powder, Nb powder, Ti powder, V powder and C powder gross mass.

4. preparation method according to claim 1, which is characterized in that in the step (1), milling time is 10 ~ 30 min。

5. preparation method according to claim 1, which is characterized in that in the step (2), heating rate in sintering process For 5 ~ 10 DEG C/min, sintering temperature is 1200 ~ 1300 DEG C, and soaking time is 30 ~ 90 min, and the flow for being passed through Ar gas is 300 ~ 400 sccm。

6. preparation method according to claim 1, which is characterized in that in the step (3), the temperature of deionized water is 80 ~100℃。

7. preparation method according to claim 1, which is characterized in that in the step (3), drying temperature is 40 ~ 80 DEG C, Drying time is 2 ~ 5 h.

8. (Ta, Nb, Ti, V) C high entropy carbide nanometer powder made from the described in any item preparation methods of claim 1-7 Body.