阅读说明：本技术 一种高纯度超细高熵陶瓷粉末及其制备方法 (High-purity superfine high-entropy ceramic powder and preparation method thereof ) 是由 杨军 孙奇春 刘维民 朱圣宇 程军 于 2019-12-16 设计创作，主要内容包括：本发明公开了一种高纯度超细高熵陶瓷粉的制备方法,是将HfO<Sub>2</Sub>、MoO<Sub>3</Sub>、Nb<Sub>2</Sub>O<Sub>5</Sub>、Ta<Sub>2</Sub>O<Sub>5</Sub>、TiO<Sub>2</Sub>、蔗糖按一定比例置于球磨机中并加入蒸馏水混合,然后经烘干过目处理得到粒径为0.15~5μm的混合粉末；随后将混合粉末装入石墨模具中,置于放电等离子烧结炉中烧结；烧结结束后,随炉冷却至室温,即得高熵陶瓷粉末。本发明制备的高熵陶瓷粉末具有较高的纯度和较小的粒径,有利于降低陶瓷材料的烧结温度,更加易于致密化,特别适用于制备在超高温工况下服役的具有性质稳定的陶瓷块体；另外,本发明可通过调整配方和工艺参数,以实现高熵陶瓷粉末材料性能的调控。(The invention discloses a preparation method of high-purity superfine high-entropy ceramic powder, which is to mix HfO 2 、MoO 3 、Nb 2 O 5 、Ta 2 O 5 、TiO 2 Placing sucrose into a ball mill according to a certain proportion, adding distilled water, mixing, and drying and screening to obtain mixed powder with the particle size of 0.15-5 mu m; then the mixed powder is put into a graphite die and is placed in a discharge plasma sintering furnace for sintering; and after sintering, cooling to room temperature along with the furnace to obtain the high-entropy ceramic powder. The high-entropy ceramic powder prepared by the invention has higher purity and smaller grain diameter, is beneficial to reducing the sintering temperature of ceramic materials, is easier to densify, and is particularly suitable for preparingPreparing a ceramic block with stable property serving under an ultrahigh-temperature working condition; in addition, the invention can realize the regulation and control of the performance of the high-entropy ceramic powder material by adjusting the formula and the process parameters.)

1. A preparation method of high-purity superfine high-entropy ceramic powder is prepared from the following raw materials and processes:

the raw material ratio is as follows: HfO in mass percent ₂：13～16 %，MoO ₃：9～11 %，Nb ₂O ₅：8～10 %，Ta ₂O ₅：14～17 %，TiO ₂: 5-6%, sucrose powder: 40-51%;

the preparation process comprises the following steps: putting the raw materials into a ball mill, adding distilled water, mixing, and drying and screening to obtain mixed powder with the particle size of 0.15-5 microns; then the mixed powder is put into a graphite die and is placed in a discharge plasma sintering furnace for sintering; and after sintering, cooling to room temperature along with the furnace to obtain the high-entropy ceramic powder.

2. The method for preparing a high-purity ultrafine high-entropy ceramic powder according to claim 1, characterized in that: the sintering parameters are as follows: vacuum degree of 10 ^-2～10 ^-1Pa, the temperature rising speed is 50-150 ℃, the sintering temperature is 1900-2100 ℃, the pressure is 3-5 MPa, and the heat preservation time is 15-30 min.

3. The method for preparing a high-purity ultrafine high-entropy ceramic powder according to claim 1, characterized in that: the composition of the high-entropy ceramic powder is (Hf-Mo-Nb-Ta-Ti) C.

Technical Field

The invention relates to high-entropy ceramic powder, in particular to high-purity superfine high-entropy ceramic powder and a preparation method thereof, belonging to the technical field of ceramic nano materials.

Background

The reliability and stability of the structural material play a key role in the safe, stable and efficient operation of high-end equipment mechanical systems. With the rapid development of high and new technologies, the service conditions of nuclear reactors, jet engines, rocket nozzles, supersonic aircrafts and the like of the new generation are more and more rigorous, and the demand on ultra-high temperature materials is more urgent. Because the existing ultrahigh-temperature ceramic cannot meet the requirements under extreme working conditions, research and development of ultrahigh-temperature ceramic materials are concerned.

In recent years, with the rapid development of high-entropy alloys, the research of high-entropy ceramic materials has attracted great attention. Compared with the existing ultrahigh-temperature ceramic material, the high-entropy ceramic mainly shows more excellent comprehensive properties such as high hardness, strength, elastic modulus, oxidation resistance, high-temperature stability and the like. However, the difficulty in preparing the high-entropy ceramic material is an important factor for limiting the application of the high-entropy ceramic material.

Disclosure of Invention

The invention aims to provide high-purity superfine high-entropy ceramic powder and a preparation method thereof.

Preparation of high-entropy ceramic powder

The high-purity superfine high-entropy ceramic powder is prepared from the following raw materials by the following process:

the raw material ratio is as follows: HfO in mass percent ₂：13～16 %，MoO ₃：9～11 %，Nb ₂O ₅：8～10 %，Ta ₂O ₅：14～17 %，TiO ₂: 5-6%, sucrose powder: 40-51%;

the preparation process comprises the following steps: putting the raw materials into a ball mill, adding distilled water, mixing, and drying and screening to obtain mixed powder with the particle size of 0.15-5 microns; then the mixed powder is put into a graphite die and is placed in a discharge plasma sintering furnace for sintering; and after sintering, cooling to room temperature along with the furnace to obtain the high-entropy ceramic powder.

The sintering parameters are as follows: vacuum degree of 10 ^-2～10 ^-1Pa, the heating rate is 50-150 ℃/min, the sintering temperature is 1800-2100 ℃, the pressure is 3-5 MPa, and the heat preservation time is 15-30 min; and after sintering, cooling to room temperature along with the furnace to obtain the high-entropy ceramic powder.

Characterization of high entropy ceramic powder

And analyzing the phase composition, purity and particle size of the sintered high-entropy ceramic powder by using an X-ray diffractometer and a scanning electron microscope.

FIG. 1 shows the morphology of a scanning electron microscope of the high-entropy ceramic powder prepared by the invention. As can be seen from FIG. 1, the high-entropy ceramic powder prepared by the invention has an average particle size of 100-300 nm, has higher purity and smaller particle size, is beneficial to reducing the sintering temperature of the ceramic material, and is easier to densify.

FIG. 2 is an X-ray diffraction pattern of the high-entropy ceramic powder prepared by the invention. As can be seen from FIG. 1, the composition of the high-entropy ceramic powder prepared by the present invention is (Hf-Mo-Nb-Ta-Ti) C. The purity reaches more than 99 percent.

In conclusion, from the perspective of preparing high-purity ultrafine high-entropy ceramic powder, sucrose is used as a carbon source, so that the sucrose can be uniformly mixed with reactants, agglomeration is reduced, and carbon generated by decomposition of the sucrose at high temperature has smaller particle size, is easier to participate in reaction, and is beneficial to improving sintering behavior, particle size distribution and uniformity of materials; with HfO ₂、MoO ₃、Nb ₂O ₅、Ta ₂O ₅、TiO ₂Sucrose and sucrose are used as reaction precursors, and the high-entropy carbide powder prepared by high-temperature sintering has higher purity and smaller particle size, and is particularly suitable for preparing ceramic blocks with stable properties serving under the ultra-high temperature working condition; in addition, the invention can realize the regulation and control of the performance of the high-entropy ceramic powder material by adjusting the formula and the process parameters.

Drawings

FIG. 1 is a scanning electron microscope of the high-entropy ceramic powder prepared by the invention.

FIG. 2 is an X-ray diffraction pattern of the high-entropy ceramic powder prepared by the present invention.

Detailed Description

The preparation and morphology of the high-entropy ceramic powder of the invention are further described by the following specific examples.