High-entropy rare earth ceramic powder, rapid preparation method and application thereof

Abstract

The application discloses high-entropy rare earth ceramic powder, a rapid preparation method and application thereof. The rapid preparation method of the high-entropy rare earth ceramic powder comprises the following steps: 1) mixing rare earth oxide powder with one of HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder uniformly to obtain a mixed powder; and 2) performing laser radiation heating on the mixed powder to obtain the high-entropy rare earth ceramic powder. The high-entropy rare earth ceramic powder has the excellent characteristics of uniform element distribution, no impurity phase and large synthesis component space, and the preparation method has the advantages of universality, simplicity, rapidness, high efficiency and the like, can realize the purpose of high-throughput screening of materials, is suitable for being used on a hot end part of an aerospace engine and has a very wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-entropy ceramic materials, and in particular to a high-entropy rare earth ceramic powder, a rapid preparation method thereof and application. BACKGROUND

[0002] High-entropy rare earth oxides are considered to be inorganic compound solid solutions, in which one or more Wyckoff sites are occupied by four or more rare earth elements, and the proportion of each rare earth element is 5at.% to 35at.%. Due to the unlimited possibilities of composition design and performance control, high-entropy rare earth oxides have attracted extensive attention from researchers. So far, various high-entropy rare earth oxide systems, including high-entropy rare earth hafnate ceramics, high-entropy rare earth zirconate ceramics, high-entropy rare earth tantalate ceramics, high-entropy rare earth monosilicate ceramics, and high-entropy rare earth disilicate ceramics, have been developed. High-entropy rare earth hafnate ceramics, high-entropy rare earth zirconate ceramics, and high-entropy rare earth tantalate ceramics have a thermal expansion coefficient that matches that of nickel-based high-temperature alloys, and have good high-temperature phase stability and outstanding thermal stress resistance, and are widely used in thermal barrier coatings. High-entropy rare earth monosilicate ceramics and high-entropy rare earth disilicate ceramics have excellent physicochemical compatibility with silicon-based ceramic substrates, and have good high-temperature phase stability, outstanding CMAS resistance, and excellent water and oxygen corrosion resistance, and are considered to be the best candidate materials for the next generation of environmental barrier coatings, and have very broad application prospects in the hot end components of aerospace engines.

[0003] However, there are few reports on the preparation method of high-entropy rare earth ceramic powder at present, and its synthesis is mainly achieved by a solid-phase reaction method. The solid-phase reaction method has the advantages of low cost, large output, and simple preparation process, and is the most commonly used method for synthesizing high-entropy rare earth ceramic powder at present (Equiatomic quaternary (Y 1 / 4 Ho 1 / 4 Er 1 / 4 Yb 1 / 4 )2SiO5 silicate: A perspective multifunctional thermal and environmental barrier coating material, Xiaomin Ren, Zhilin Tian, Jie Zhang, Jingyang Wang. Scripta Materialia, 2019, 168: 47-5; High-entropy ferroelastic rare-earth tantalite ceramic: (Y 0.2 Ce 0.2 Sm 0.2 Gd 0.2 Dy 0.2TaO4, Jun Wang, Fushuo Wu, Ruoan Zou, Yueshu Wu, Mengdi Gan, Jing Feng, Xiaoyu Chong. Journal of American ceramic society, 2021, 104: 5873-5882), but this method has problems such as long synthesis cycle (3-4 days), small component space that can be synthesized, uneven element distribution, and impurity phase. In addition, due to the huge high-entropy component space, there is currently a lack of simple, rapid and efficient high-throughput screening method, which seriously limits the development and practical application of high-performance high-entropy rare earth ceramic materials.

[0004] Therefore, it is of great significance to develop a universal, simple, rapid, efficient and high-throughput material screening method for preparing high-entropy rare earth ceramic powder, and to prepare high-entropy rare earth ceramic powder with uniform element distribution, no impurity phase and large component space. SUMMARY

[0005] The purpose of the present application is to provide a high-entropy rare earth ceramic powder and a rapid preparation method and application thereof.

[0006] The technical scheme adopted by the present application is:

[0007] A rapid preparation method of high-entropy rare earth ceramic powder comprises the following steps:

[0008] 1) uniformly mixing rare earth oxide powder with one of HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder to obtain a mixed powder;

[0009] 2) laser irradiation heating the mixed powder to obtain the high-entropy rare earth ceramic powder.

[0010] Preferably, the rare earth oxide powder in step 1) is composed of at least four of Sc2O3 powder, Y2O3 powder, La2O3 powder, Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, Ho2O3 powder, Er2O3 powder, Tm2O3 powder, Yb2O3 powder, and Lu2O3 powder in an equimolar ratio.

[0011] Preferably, the particle size of the rare earth oxide powder, HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder in step 1) is 1-3 μm, and the purity is ≥ 99.9%.

[0012] Preferably, the molar ratio of the rare earth oxide powder and HfO2 powder in step 1) is 1:2.0-2.2.

[0013] Preferably, the molar ratio of rare earth oxide powder to ZrO2 powder in step 1) is 1:2.0 to 2.2.

[0014] Preferably, the molar ratio of rare earth oxide powder and Ta2O5 powder in step 1) is 1:1.0 to 1.1.

[0015] Preferably, the molar ratio of rare earth oxide powder to SiO2 powder in step 1) is 1:1.0–1.1 or 1:2.0–2.2. Controlling the molar ratio of rare earth oxide powder to SiO2 powder to 1:1.0–1.1 yields high-entropy rare earth monosilicate ceramic powder; controlling the molar ratio of rare earth oxide powder to SiO2 powder to 1:2.0–2.2 yields high-entropy rare earth disilicate ceramic powder.

[0016] Preferably, the specific operations of mixing in step 1) include wet ball milling, drying, and grinding.

[0017] Preferably, the process parameters for the wet ball milling include: the ball milling medium is anhydrous ethanol, the ball milling equipment is a planetary ball mill, the weight ratio of powder raw material, ZrO2 balls and anhydrous ethanol is 1:1.8~2.2:1.0~1.5, and the ball milling time is 6h~10h.

[0018] Preferably, the drying process parameters include: the drying equipment is an oven, the drying temperature is 80℃~100℃, and the drying time is 6h~8h.

[0019] Preferably, the mixed powder in step 2) is placed in a graphite crucible and compacted.

[0020] Preferably, the graphite crucible has a diameter of 12mm to 16mm and a height of 3mm to 5mm.

[0021] Preferably, the process parameters for laser radiation heating in step 2) include: laser power of 180W to 240W, duty cycle of 70% to 100%, heating temperature of 1800℃ to 2000℃, and heating time of 5s to 10s.

[0022] A high-entropy rare-earth ceramic powder is prepared by the above-mentioned rapid preparation method.

[0023] A thermal barrier / environmental barrier coating comprising the aforementioned high-entropy rare-earth ceramic powder.

[0024] An aerospace engine in which the surface of a hot-end component is covered with the aforementioned thermal barrier / environmental barrier coating.

[0025] The beneficial effects of this invention are: the high-entropy rare earth ceramic powder of this invention has excellent characteristics such as uniform element distribution, no impurity phase, and large synthesis component space, and its preparation method has the advantages of universality, simplicity, speed and efficiency, which can achieve the purpose of high-throughput screening of materials. It is suitable for use in hot-end components of aerospace engines and has a very broad application prospect.

[0026] Specifically:

[0027] 1) This invention uses laser radiation heating to synthesize high-entropy rare-earth ceramic powders, which can prepare high-entropy ceramic powders with a huge component space. This preparation method has universality (specifically: a) it can synthesize powders of various material systems, such as rare-earth hafnium salts / zirconates / tantalates / monosilicates / bisilicates, etc.; b) it can synthesize ceramic powders with 9, 10 or even higher components; c) it can also successfully prepare powders for material systems with complex phase structures, such as the β, γ, δ and G phases of bisilicates).

[0028] 2) The high-entropy rare earth ceramic powder preparation method of the present invention has the advantages of being simple (easy to operate), fast (5s~10s), efficient (can realize high-throughput preparation and performance screening), and stable and controllable process, and is suitable for large-scale promotion and application.

[0029] 3) The high-entropy rare earth ceramic powder of the present invention has excellent characteristics such as uniform element distribution, no impurity phase, and large space for synthesizing components. Attached Figure Description

[0030] Figure 1 The temperature rise curve of the mixed powder in Example 1 when subjected to laser radiation heating.

[0031] Figure 2 The images show the XRD patterns of the high-entropy rare-earth ceramic powders in Examples 1-3.

[0032] Figure 3 The images shown are SEM and SEM-EDS images of the high-entropy rare earth ceramic powder in Example 1.

[0033] Figure 4 The images show the XRD patterns of the high-entropy rare-earth ceramic powders in Examples 4 and 5.

[0034] Figure 5 The image shows the XRD pattern of the high-entropy rare-earth ceramic powder in Comparative Example 1. Detailed Implementation

[0035] The present invention will be further explained and described below with reference to specific embodiments.

[0036] The particle size of Y2O3 powder, Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, Ho2O3 powder, Er2O3 powder, Tm2O3 powder, Yb2O3 powder and Lu2O3 powder in Examples 1-5 and Comparative Examples 1-2 is 1-3 μm, and the purity is ≥99.9%.

[0037] The particle size of HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder in Examples 1-5 and Comparative Examples 1-2 is 1-3 μm, and the purity is ≥99.9%.

[0038] Example 1:

[0039] A high-entropy rare earth ceramic powder is prepared by the following method:

[0040] 1) 1.4919 g of Dy2O3 powder, 1.5114 g of Ho2O3 powder, 1.5300 g of Er2O3 powder, 1.5917 g of Lu2O3 powder and 8.4195 g of HfO2 powder are added to a ball mill tank, anhydrous ethanol is used as medium, the weight ratio of the powder raw material, ZrO2 ball and anhydrous ethanol is controlled to be 1:1.8:1.0, the mixture is ball milled on a planetary ball mill for 8 h, the obtained mixed slurry is placed in an oven and baked at 90°C for 6 h, and then ground and sieved to obtain a mixed powder;

[0041] 2) The mixed powder is loaded into a graphite crucible with a diameter of 12 mm and a height of 3 mm, and is tightly pressed, then the graphite crucible is fixed on a laser heating table by a clamp, the laser power is adjusted to 210 W and the duty cycle is adjusted to 80%, the temperature is heated to 2000°C (the heating temperature is tested by an infrared temperature measuring instrument), and the temperature is maintained for 5 s, and then the temperature is naturally cooled to room temperature, thereby obtaining a high-entropy rare earth ceramic powder (quaternary high-entropy rare earth hafnate (Dy 1 / 4 Ho 1 / 4 Er 1 / 4 Lu 1 / 4 )2Hf2O7, which is denoted as 4-HEREH.

[0042] Performance test:

[0043] 1) The temperature rising curve of the mixed powder in this embodiment when laser radiation heating is shown in Figure 1 .

[0044] It can be seen from Figure 1 that the laser heating method is radiation heating, the temperature distribution is more uniform, the temperature of the mixed powder can be raised to 2000°C within a few seconds, and the speed of the synthesized material is extremely fast.

[0045] 2) The X-ray diffraction (XRD) pattern of the high-entropy rare earth ceramic powder (4-HEREH) in this embodiment is shown inFigure 2 As shown, the scanning electron microscope (SEM) image and energy-dispersive X-ray spectroscopy (SEM-EDS) image are as follows: Figure 3 As shown.

[0046] Depend on Figure 2 It can be seen that the high-entropy rare earth ceramic powder has a single RE2Hf2O7 structure, and no other impurity phases were found.

[0047] Depend on Figure 3 It can be seen that the morphology of high-entropy rare earth ceramic powder is mainly spherical particles with an average particle size of about 300 nm. The rare earth elements are evenly distributed and there is no obvious segregation.

[0048] Example 2:

[0049] A rapid preparation method for a high-entropy rare-earth ceramic powder is as follows:

[0050] 1) Add 0.9032g of Y2O3 powder, 1.4500g of Gd2O3 powder, 1.5301g of Er2O3 powder, 1.5917g of Lu2O3 powder and 4.9288g of ZrO2 powder into a ball mill jar. Use anhydrous ethanol as the medium and control the weight ratio of powder raw materials, ZrO2 balls and anhydrous ethanol to be 1:2.0:1.2. Ball mill for 8 hours on a planetary ball mill. Then place the resulting mixed slurry in an oven and dry at 80℃ for 6 hours. Then grind and sieve to obtain mixed powder.

[0051] 2) The mixed powder is placed into a graphite crucible with a diameter of 14 mm and a height of 4 mm, pressed firmly, and then the graphite crucible is fixed on the laser heating stage with a clamp. The laser power is adjusted to 180 W and the duty cycle to 95%, and the temperature is heated to 1900℃ (the heating temperature is measured with an infrared thermometer). The temperature is held for 10 seconds, and then allowed to cool naturally to room temperature to obtain high-entropy rare earth ceramic powder (quaternary high-entropy rare earth zirconate (Y)). 1 / 4 Gd 1 / 4 Er 1 / 4 Lu 1 / 4 )2Zr2O7, denoted as 4-HEREZ).

[0052] Performance testing:

[0053] The XRD pattern of the high-entropy rare-earth ceramic powder (4-HEREZ) in this embodiment is as follows: Figure 2 As shown.

[0054] Depend on Figure 2 It can be seen that the high-entropy rare earth ceramic powder has a single RE2Zr2O7 structure, and no other impurity phases were found.

[0055] Example 3:

[0056] A rapid preparation method for a high-entropy rare-earth ceramic powder is as follows:

[0057] 1) Put 0.9253 g of Nd2O3 powder, 0.9590 g of Sm2O3 powder, 0.9969 g of Gd2O3 powder, 0.9678 g of Eu2O3 powder and 4.8608 g of Ta2O5 powder into a ball mill tank, take absolute ethanol as the medium, control the weight ratio of the powder raw material, ZrO2 ball and absolute ethanol to be 1:2.0:1.2, ball mill on a planetary ball mill for 7 h, then put the obtained mixed slurry into an oven and bake at 90 ℃ for 8 h, and then grind and sieve to obtain a mixed powder;

[0058] 2) Put the mixed powder into a graphite crucible with a diameter of 15 mm and a height of 4 mm, press it tightly, then fix the graphite crucible on a laser heating table with a clamp, adjust the laser power to 180 W and the duty cycle to 90%, heat to 1800 ℃ (the heating temperature is tested by an infrared temperature tester), keep for 6 s, and naturally cool to room temperature to obtain a high-entropy rare earth ceramic powder (quaternary high-entropy rare earth tantalate (Nd 1 / 4 Sm 1 / 4 Gd 1 / 4 Eu 1 / 4 )TaO4, denoted as 4-HERET).

[0059] Performance test:

[0060] The XRD pattern of the high-entropy rare earth ceramic powder (4-HERET) in this embodiment is shown in Figure 2 .

[0061] It can be known from Figure 2 that the high-entropy rare earth ceramic powder is a single RETaO4 structure, and no other impurities are found.

[0062] Example 4:

[0063] A high-entropy rare earth ceramic powder is prepared by the following rapid preparation method:

[0064] 1) Put 2.8339 g of Ho2O3 powder, 2.8688 g of Er2O3 powder, 2.9557 g of Yb2O3 powder, 2.9845 g of Lu2O3 powder and 1.8025 g of SiO2 powder into a ball mill tank, take absolute ethanol as the medium, control the weight ratio of the powder raw material, ZrO2 ball and absolute ethanol to be 1:1.8:1.2, ball mill on a planetary ball mill for 8 h, then put the obtained mixed slurry into an oven and bake at 80 ℃ for 6 h, and then grind and sieve to obtain a mixed powder;

[0065] 2) Put the mixed powder into a graphite crucible with a diameter of 16 mm and a height of 3 mm, press it tightly, then fix the graphite crucible on the laser heating table with a clamp, adjust the laser power to 180 W and the duty cycle to 95%, heat to 1800℃ (the heating temperature is tested by an infrared temperature tester), keep warm for 6s, and naturally cool to room temperature to obtain the high-entropy rare earth ceramic powder (quaternary high-entropy earth single silicate (Ho 1 / 4 Er 1 / 4 Yb 1 / 4 Lu 1 / 4 )2SiO5, denoted as 4-HEREM).

[0066] Performance test:

[0067] The XRD pattern of the high-entropy rare earth ceramic powder (4-HEREM) in this example is shown in Figure 4 .

[0068] As can be seen from Figure 4 , the high-entropy rare earth ceramic powder has a single X2-RE2SiO5 structure, and no other impurities are found.

[0069] Example 5:

[0070] A high-entropy rare earth ceramic powder is prepared by the following rapid preparation method:

[0071] 1) Put 2.2952g of Er2O3 powder, 2.2673g of Ho2O3 powder, 2.3153g of Tm2O3 powder, 2.2381g of Dy2O3 powder and 2.8841g of SiO2 powder into a ball mill tank, use anhydrous ethanol as the medium, control the weight ratio of the powder raw material, ZrO2 ball and anhydrous ethanol to be 1:2.2:1.5, ball mill on a planetary ball mill for 10h, then put the obtained mixed slurry into an oven at 100℃ for 8h, then grind and sieve to obtain the mixed powder;

[0072] 2) Put the mixed powder into a graphite crucible with a diameter of 16 mm and a height of 5 mm, press it tightly, then fix the graphite crucible on the laser heating table with a clamp, adjust the laser power to 240 W and the duty cycle to 100%, heat to 2000℃ (the heating temperature is tested by an infrared temperature tester), keep warm for 10s, and naturally cool to room temperature to obtain the high-entropy rare earth ceramic powder (quaternary high-entropy earth double silicate (Er 1 / 4 Ho 1 / 4 Tm 1 / 4 Dy 1 / 4 )2Si2O7, denoted as 4-HERED).

[0073] Performance test:

[0074] The XRD pattern of the high-entropy rare earth ceramic powder (4-HERED) in this example is shown inFigure 4 As shown in FIG. 1.

[0075] As shown in FIG. 2. Figure 4 It can be seen that the high-entropy rare earth ceramic powder is a single γ-RE2Si2O7 structure, and no other impurities are found.

[0076] Comparative Example 1:

[0077] A high-entropy rare earth ceramic powder (denoted as Sample-1) is prepared in the same way as Example 5, except that the laser irradiation heating in step 2) is replaced by muffle calcination (1500℃, 3h).

[0078] Performance test:

[0079] The XRD pattern of the high-entropy rare earth ceramic powder (denoted as Sample-1) in the present comparative example is shown in FIG. 1. Figure 5 As shown in FIG. 1.

[0080] As shown in FIG. 2. Figure 5 It can be seen that the high-entropy rare earth ceramic powder prepared by the commonly used solid phase reaction method has impurities, which is because there are many types of double silicate phases, commonly known as β, γ, δ and G phases, and phase transitions will occur between each phase. When the number of rare earth elements is large or the difference is large, it is difficult to synthesize a pure phase by using the traditional solid phase reaction method.

[0081] Comparative Example 2:

[0082] A high-entropy rare earth ceramic powder (denoted as Sample-2) is prepared in the same way as Example 5, except that the laser power is 150W and the duty cycle is 60% in step 2) instead of 240W and 100%, and the heating temperature is 1500℃ instead of 2000℃.

[0083] Performance test:

[0084] The XRD pattern of the high-entropy rare earth ceramic powder (denoted as Sample-2) in the present comparative example is shown in FIG. 2. Figure 5 As shown in FIG. 2.

[0085] As shown in FIG. 2. Figure 5 It can be seen that when the laser power and the duty cycle are low, the laser irradiation heating temperature is also low, so the high-entropy rare earth ceramic powder prepared has many impurities, which is because the laser irradiation heating temperature is not high enough to provide enough driving force.

[0086] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A rapid preparation method for high-entropy rare-earth ceramic powder, characterized in that, Includes the following steps: 1) Mix rare earth oxide powder with one of HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder to obtain a mixed powder; 2) The mixed powder is heated by laser radiation to obtain high-entropy rare earth ceramic powder; Step 1) The rare earth oxide powder is composed of at least four of the following powders in equimolar ratio: Sc2O3 powder, Y2O3 powder, La2O3 powder, Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, Ho2O3 powder, Er2O3 powder, Tm2O3 powder, Yb2O3 powder, and Lu2O3 powder. In step 1), the molar ratio of rare earth oxide powder to HfO2 powder is 1:2.0 to 2.

2. In step 1), the molar ratio of rare earth oxide powder to ZrO2 powder is 1:2.0 to 2.

2. In step 1), the molar ratio of rare earth oxide powder to Ta2O5 powder is 1:1.0 to 1.

1. In step 1), the molar ratio of rare earth oxide powder to SiO2 powder is 1:1.0 to 1.1 or 1:2.0 to 2.

2. Step 2) The process parameters for laser radiation heating include: laser power of 180W to 240W, duty cycle of 70% to 100%, heating temperature of 1800℃ to 2000℃, and heating time of 5s to 10s.

2. The rapid preparation method according to claim 1, characterized in that: The particle size of the rare earth oxide powder, HfO2 powder, ZrO2 powder, Ta2O5 powder and SiO2 powder mentioned in step 1) is 1μm to 3μm, and the purity is ≥99.9%.

3. The rapid preparation method according to claim 1, characterized in that: Step 1) The specific operation of mixing includes wet ball milling, drying and grinding; the process parameters of wet ball milling include: the ball milling medium is anhydrous ethanol, the ball milling equipment is a planetary ball mill, the weight ratio of powder raw material, ZrO2 balls and anhydrous ethanol is 1:1.8~2.2:1.0~1.5, and the ball milling time is 6h~10h.

4. The rapid preparation method according to claim 1, characterized in that: Step 2) The mixed powder is placed in a graphite crucible and compacted.

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