High-entropy rare earth oxide wave-absorbing powder as well as preparation method and application thereof

Abstract

The invention discloses high-entropy rare earth oxide wave-absorbing powder as well as a preparation method and application thereof. The preparation method of the high-entropy rare earth oxide wave-absorbing powder comprises the following steps: 1) mixing rare earth oxide powder with one of SiO2 powder, ZrO2 powder, HfO2 powder, Al2O3 powder, Nb2O5 powder and Ta2O5 powder to obtain mixed powder; and 2) carrying out high-power laser radiation heating on the mixed powder to obtain the high-entropy rare earth oxide wave-absorbing powder. The preparation method of the high-entropy rare earth oxide wave-absorbing powder has the advantages that the high-entropy rare earth oxide can be endowed with the intrinsic wave-absorbing characteristic without depending on a second phase, the self performance of the high-entropy rare earth oxide is not influenced, the universality is high, and the prepared high-entropy rare earth oxide wave-absorbing powder has excellent electromagnetic wave absorbing performance and is suitable for being used in the field of electromagnetic wave absorption. The coating is suitable for being used as a thermal protection stealth coating to be applied to aerospace engine hot end components, and has very wide application prospects.

Description

TECHNICAL FIELD

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

[0002] High-entropy rare earth oxides are inorganic compound solid solutions in which one or more Wyckoff sites are occupied by four or more rare earth elements. They have unlimited possibilities for composition design and performance control, and usually have excellent thermal insulation and corrosion resistance, making them ideal materials for thermal protection coatings of high-temperature hot end components of aero-engines, and have a very broad application prospect. With the development of aero-engines towards high thrust-to-weight ratio, high efficiency, low fuel consumption, long service life, and stealth, high-temperature thermal protection coatings not only need to have excellent thermal protection performance, but also need to have electromagnetic wave stealth characteristics. However, the dielectric loss of existing high-entropy rare earth oxides is generally low, which makes it difficult to absorb electromagnetic waves and fundamentally unable to endow the thermal protection coating with electromagnetic wave stealth characteristics, limiting its application on high-temperature hot end components of future aero-engines.

[0003] Cheng et al. achieved the conversion of the effective wave absorption bandwidth from 0 to 3.6 GHz by compounding SiC phase with wave-absorbing properties in the rare earth oxide Sc2Si2O7 matrix (A novel SiC-based microwave absorption ceramic with Sc2Si2O7 as transparent matrix, Hanjun Wei, Xiaowei Yin, Zexin Hou, Fengrui Jiang, Hailong Xu, Minghang Li, Litong Zhang, Laifei Cheng. Journal of the European Ceramic Society, 2018, 38:4189-4197). This method has the advantages of simple preparation process and large synthesis yield, but it needs to rely on a second phase (the wave-absorbing property mainly comes from the introduced second phase, which needs to be strictly controlled), and does not change the wave-absorbing property of the rare earth oxide from the intrinsic point of view. Moreover, it also has the problems of weakening the performance of the rare earth oxide itself (CMAS resistance and water and oxygen corrosion resistance), poor universality (mainly suitable for rare earth silicate systems), and cannot fully meet the requirements of practical application.

[0004] Therefore, it is of great significance to develop a preparation method of high-entropy rare earth oxide wave-absorbing powder which does not rely on a second phase to endow the high-entropy rare earth oxide with intrinsic wave-absorbing property, does not affect the performance of the high-entropy rare earth oxide itself, and has strong universality. SUMMARY

[0005] The application aims to provide a high-entropy rare earth oxide wave-absorbing powder, a preparation method and application thereof.

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

[0007] A preparation method of a high-entropy rare earth oxide wave-absorbing powder comprises the following steps:

[0008] 1) mixing one of a rare earth oxide powder, a SiO2 powder, a ZrO2 powder, a HfO2 powder, an Al2O3 powder, a Nb2O5 powder and a Ta2O5 powder to obtain a mixed powder;

[0009] 2) performing high-power laser radiation heating on the mixed powder to obtain the high-entropy rare earth oxide wave-absorbing powder.

[0010] Preferably, the rare earth oxide powder in step 1) is composed of at least four of Sc2O3 powder, Y2O3 powder, La2O3 powder, CeO2 powder, Pr6O 11 Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Tb4O7 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, the SiO2 powder, the ZrO2 powder, the HfO2 powder, the Al2O3 powder, the Nb2O5 powder and the Ta2O5 powder in step 1) is 1-3 microns, and the purity is greater than or equal to 99.9%.

[0012] Preferably, the molar ratio of the rare earth oxide powder to the SiO2 powder in step 1) is 1:1.0-1.1 or 1:2.0-2.2 (the molar ratio of the rare earth oxide powder to the SiO2 powder is 1:1.0-1.1 to obtain a high-entropy rare earth monosilicate wave-absorbing powder; the molar ratio of the rare earth oxide powder to the SiO2 powder is 1:2.0-2.2 to obtain a high-entropy rare earth disilicate wave-absorbing powder).

[0013] Preferably, the molar ratio of the rare earth oxide powder to the ZrO2 powder in step 1) is 1:2.0-2.2 (to obtain a high-entropy rare earth zirconate wave-absorbing powder).

[0014] Preferably, the molar ratio of the rare earth oxide powder to the HfO2 powder in step 1) is 1:2.0-2.2 (to obtain a high-entropy rare earth hafnate wave-absorbing powder).

[0015] Preferably, the molar ratio of the rare earth oxide powder to the Al2O3 powder in step 1) is 1:1.0-1.1 (to obtain a high-entropy rare earth aluminate wave-absorbing powder).

[0016] Preferably, the molar ratio of the rare earth oxide powder and the Nb2O5 powder in step 1) is 1:1.0-1.1 (to obtain a high-entropy rare earth niobate wave-absorbing powder).

[0017] Preferably, the molar ratio of the rare earth oxide powder and the Ta2O5 powder in step 1) is 1:1.0-1.1 (to obtain a high-entropy rare earth tantalate wave-absorbing powder).

[0018] Preferably, the mixing in step 1) comprises wet ball milling, drying and grinding.

[0019] Preferably, the process parameters of the wet ball milling comprise: the ball milling medium is anhydrous ethanol, the ball milling equipment is a planetary ball mill, the weight ratio of the powder raw material, ZrO2 balls and anhydrous ethanol is 1:1.8-2.2:1.0-1.5, and the ball milling time is 6-10 h.

[0020] Preferably, the drying is performed at a temperature of 80-100℃, and the drying time is 6-8 h.

[0021] Preferably, the mixed powder in step 2) is placed in a graphite crucible and compacted before high-power laser irradiation heating.

[0022] Preferably, the process parameters of the high-power laser irradiation heating in step 2) comprise: the laser power is 1000-1500 W, the duty cycle is 90%-100%, the heating temperature is 2800-3500℃, and the heating time is 2-5 s.

[0023] A high-entropy rare earth oxide wave-absorbing powder prepared by the above preparation method.

[0024] A thermal protection stealth coating comprising the above high-entropy rare earth oxide wave-absorbing powder.

[0025] An aerospace engine, wherein the surface of the hot end component is covered with the above thermal protection stealth coating.

[0026] The high-entropy rare earth oxide wave-absorbing powder preparation method of the present application has the advantages of not relying on a second phase to endow the high-entropy rare earth oxide with intrinsic wave-absorbing properties, not affecting the performance of the high-entropy rare earth oxide itself, and strong universality, and the prepared high-entropy rare earth oxide wave-absorbing powder has excellent electromagnetic wave absorption performance, is suitable for application in a thermal protection stealth coating of an aerospace engine hot end component, and has a very broad application prospect.

[0027] Specifically:

[0028] 1) The preparation method of the high-entropy rare earth oxide wave-absorbing powder of the present application is to construct vacancy defects of sufficient concentration by using high-power laser radiation heating, to enhance the electric conduction loss and the dipole polarization loss, to convert the wave-transparent material into a wave-absorbing material, and to endow the high-entropy rare earth oxide with intrinsic wave-absorbing properties without adding a second phase, which does not affect the water-oxygen resistance and CMAS corrosion resistance of the high-entropy rare earth oxide itself;

[0029] 2) The preparation method of the high-entropy rare earth oxide wave-absorbing powder of the present application has the advantages of rapidness (the time of high-power laser radiation heating only needs 2s-5s) and process stability and controllability, and is suitable for large-scale industrial application;

[0030] 3) The preparation method of the high-entropy rare earth oxide wave-absorbing powder of the present application is suitable for various high-entropy rare earth oxide systems, which can not only prepare high-entropy rare earth monosilicates, high-entropy rare earth disilicates, high-entropy rare earth zirconates, high-entropy rare earth hafnates, high-entropy rare earth aluminates, high-entropy rare earth niobates, high-entropy rare earth tantalates and other high-entropy rare earth oxide systems, but also can synthesize high-entropy rare earth oxide systems with complex phase structures, and in addition, even can successfully synthesize high-entropy rare earth oxide powders with 15, 16 or even more components, which has strong universality. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The XRD patterns of the high-entropy rare earth oxide wave-absorbing powders in Example 1 and Example 2.

[0032] Figure 2 The XRD patterns of the high-entropy rare earth oxide wave-absorbing powders in Example 3-7.

[0033] Figure 3 The reflection loss test results of the high-entropy rare earth oxide wave-absorbing powders in Example 1-7.

[0034] Figure 4 The XRD patterns of the high-entropy rare earth oxide powders in Comparative Example 1 and Comparative Example 2.

[0035] Figure 5 The reflection loss test results of the high-entropy rare earth oxide powders in Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0036] The present application will be further explained and described below in conjunction with specific examples.

[0037] The particle size of the Y2O3 powder, La2O3 powder, CeO2 powder, Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Dy2O3 powder, Ho2O3 powder, Er2O3 powder, Tm2O3 powder, Yb2O3 powder and Lu2O3 powder in Examples 1-7 and Comparative Examples 1-2 is 1-3 μm, and the purity is all ≥99.9%.

[0038] The particle size of the SiO2 powder, ZrO2 powder, HfO2 powder, Al2O3 powder, Nb2O5 powder and Ta2O5 powder in Examples 1-7 and Comparative Examples 1-2 is 1-3 μm, and the purity is all ≥99.9%.

[0039] Example 1:

[0040] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0041] 1) 1.9549 g of La2O3 powder, 2.1750 g of Gd2O3 powder, 2.2380 g of Dy2O3 powder, 2.3876 g of Yb2O3 powder, 2.3876 g of Lu2O3 powder and 1.8025 g of SiO2 powder are added to a planetary ball mill for wet ball milling, and the process parameters of wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 ball and anhydrous ethanol is 1:2:1.2, the ball milling time is 6 h, the obtained slurry is placed in an oven at 90°C for 7 h, then taken out, cooled to room temperature and ground, and then sieved through a 100-mesh sieve (remove the residue), to obtain a mixed powder;

[0042] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating, and the process parameters of high-power laser radiation heating are as follows: the laser power is 1400 W, the duty cycle is 90%, the heating temperature is 3300°C, and the heating time is 4 s, and then cooled to room temperature, to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy rare earth monosilicate (La 1 / 5 Gd 1 / 5 Dy 1 / 5 Yb 1 / 5 Lu 1 / 5 )2SiO5, denoted as 5-HEREM.

[0043] Example 2:

[0044] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0045] 1) 1.3033 g of La2O3 powder, 1.6824 g of Nd2O3 powder, 1.7436 g of Sm2O3 powder, 2.4077 g of Eu2O3 powder, 1.4920 g of Dy2O3 powder, and 2.4033 g of SiO2 powder are added to a planetary ball mill for wet ball milling, and the process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls, and anhydrous ethanol is 1:2:1.2, and the ball milling time is 6 h; the obtained slurry is then placed in an oven at 90°C for 7 h, taken out, cooled to room temperature, and then ground, and the ground product is sieved through a 100-mesh sieve (the sieve residue is removed) to obtain a mixed powder;

[0046] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating, and the process parameters for high-power laser radiation heating are as follows: the laser power is 1200 W, the duty cycle is 95%, the heating temperature is 3200°C, and the heating time is 4 s; and then cooled to room temperature to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy rare earth double-silicate (La 1 / 5 Nd 1 / 5 Sm 1 / 5 Eu 1 / 5 Dy 1 / 5 )2Si2O7, denoted as 5-HERED.

[0047] Example 3:

[0048] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0049] 1) 1.3549 g of Y2O3 powder, 2.1750 g of Gd2O3 powder, 2.2951 g of Er2O3 powder, 2.3646 g of Yb2O3 powder, 2.3876 g of Lu2O3 powder, and 7.3933 g of ZrO2 powder are added to a planetary ball mill for wet ball milling, and the process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls, and anhydrous ethanol is 1:2:1.2, and the ball milling time is 6 h; the obtained slurry is then placed in an oven at 90°C for 7 h, taken out, cooled to room temperature, and then ground, and the ground product is sieved through a 100-mesh sieve (the sieve residue is removed) to obtain a mixed powder;

[0050] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating, and the process parameters for high-power laser radiation heating are as follows: the laser power is 1200 W, the duty cycle is 90%, the heating temperature is 3000°C, and the heating time is 4 s; and then cooled to room temperature to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy rare earth double-silicate (La 1 / 5 Gd 1 / 5 Er1 / 5 Yb 1 / 5 Lu 1 / 5 )2Zr2O7, denoted as 5-HEREZ).

[0051] Example 4:

[0052] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0053] 1) 2.2380 g of Dy2O3 powder, 2.2671 g of Ho2O3 powder, 2.2951 g of Er2O3 powder, 2.3152 g of Tm2O3 powder, 2.3876 g of Lu2O3 powder, and 12.6293 g of HfO2 powder are added to a planetary ball mill for wet ball milling, and the process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls, and anhydrous ethanol is 1:2:1.2, the ball milling time is 6 h, the obtained slurry is then placed in an oven at 90°C for 7 h, and then taken out, cooled to room temperature, and ground, and then sieved through a 100-mesh sieve (remove the residue), to obtain a mixed powder;

[0054] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating, and the process parameters for high-power laser radiation heating are as follows: the laser power is 1100 W, the duty cycle is 90%, the heating temperature is 3100°C, and the heating time is 4 s, and then cooled to room temperature, to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy earth hafnate, Dy 1 / 5 Ho 1 / 5 Er 1 / 5 Tm 1 / 5 Lu 1 / 5 )2Hf2O7, denoted as 5-HEREH).

[0055] Example 5:

[0056] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0057] 1) 2.0323 g of Y2O3 powder, 3.4007 g of Ho2O3 powder, 3.4427 g of Er2O3 powder, 3.2625 g of Dy2O3 powder, 2.3876 g of Gd2O3 powder, and 7.6468 g of Al2O3 powder are added to a planetary ball mill for wet ball milling, and the process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls, and anhydrous ethanol is 1:2:1.2, the ball milling time is 6 h, the obtained slurry is then placed in an oven at 90°C for 7 h, and then taken out, cooled to room temperature, and ground, and then sieved through a 100-mesh sieve (remove the residue), to obtain a mixed powder;

[0058] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating. The process parameters for high-power laser radiation heating are as follows: laser power is 1200 W, duty cycle is 95%, heating temperature is 3200 DEG C, heating time is 4 s, and then cooled to room temperature to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy earth aluminates (Y 1 / 5 Ho 1 / 5 Er 1 / 5 Dy 1 / 5 Gd 1 / 5 )3Al5O 12 , denoted as 5-HEREA).

[0059] Example 6:

[0060] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0061] 1) 2.3876 g of Lu2O3 powder, 2.2671 g of Ho2O3 powder, 2.2951 g of Er2O3 powder, 1.3549 g of Y2O3 powder, 2.3646 g of Yb2O3 powder, and 7.0143 g of Nb2O5 powder are added to a planetary ball mill for wet ball milling. The process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls, and anhydrous ethanol is 1:2:1.2, and the ball milling time is 6 h. The obtained slurry is then placed in an oven at 90 DEG C for 7 h, and then cooled to room temperature and ground. The ground material is sieved through a 100-mesh sieve (with the sieve residue removed) to obtain a mixed powder;

[0062] 2) The mixed powder is placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating. The process parameters for high-power laser radiation heating are as follows: laser power is 1300 W, duty cycle is 90%, heating temperature is 3000 DEG C, heating time is 4 s, and then cooled to room temperature to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy earth niobate (Lu 1 / 5 Ho 1 / 5 Er 1 / 5 Y 1 / 5 Yb 1 / 5 )NbO4, denoted as 5-HEREN).

[0063] Example 7:

[0064] A high-entropy rare earth oxide wave-absorbing powder is prepared by the following method:

[0065] 1) 1.3549 g of Y2O3 powder, 2.0654 g of CeO2 powder, 2.0923 g of Sm2O3 powder, 2.1750 g of Gd2O3 powder, 2.2380 g of Dy2O3 powder and 13.2569 g of Ta2O5 powder were added to a planetary ball mill for wet ball milling, and the process parameters for wet ball milling were as follows: the ball milling medium was anhydrous ethanol, the weight ratio of the powder raw material, ZrO2 balls and anhydrous ethanol was 1:2:1.2, the ball milling time was 6 h, the slurry obtained by grinding was placed in an oven at 90°C for 7 h, and then taken out and cooled to room temperature for grinding, and then sieved through a 100-mesh sieve (the residue was removed) to obtain a mixed powder;

[0066] 2) The mixed powder was placed in a graphite crucible and compacted, and then placed on a laser heating device for high-power laser radiation heating, and the process parameters for high-power laser radiation heating were as follows: the laser power was 1100 W, the duty cycle was 95%, the heating temperature was 3100°C, and the heating time was 4 s, and then cooled to room temperature to obtain a high-entropy rare earth oxide wave-absorbing powder (a five-element high-entropy rare earth tantalate (Y 1 / 5 Ce 1 / 5 Sm 1 / 5 Gd 1 / 5 Dy 1 / 5 )TaO4, denoted as 5-HERET.

[0067] Comparative Example 1:

[0068] A high-entropy rare earth oxide powder (denoted as Sample-1) was prepared in the same way as in Example 1, except that the high-power laser radiation heating in step 2) was replaced by muffle furnace calcination (1500°C, 3 h).

[0069] Comparative Example 2:

[0070] A high-entropy rare earth oxide powder (denoted as Sample-2) was prepared in the same way as in Example 1, except that the process parameters for high-power laser radiation heating in step 2) were adjusted from “laser power 1400 W, duty cycle 90%, heating temperature 3300°C, heating time 4 s” to “laser power 300 W, duty cycle 90%, heating temperature 1800°C, heating time 4 s”.

[0071] Performance Test:

[0072] 1) The X-ray diffraction (XRD) patterns of the high-entropy rare earth oxide wave-absorbing powders (5-HEREM and 5-HERED) in Example 1 and Example 2 are as follows: Figure 1As shown, the XRD patterns of the high-entropy rare-earth oxide absorbing powders (5-HEREZ, 5-HEREH, 5-HEREA, 5-HEREN, and 5-HERET) in Examples 3-7 are as follows. Figure 2 As shown.

[0073] Depend on Figure 1 It can be known that:

[0074] a) 5-HEREM showed a single RE2SiO5 structure with no other impurity phases detected;

[0075] b) 5-HERED has a single RE2Si2O7 structure, and no other impurity phases were found.

[0076] Depend on Figure 2 It can be known that:

[0077] a) 5-HEREZ has a single RE2Zr2O7 structure, and no other impurity phases were found;

[0078] b) 5-HEREH has a single RE2Hf2O7 structure, and no other impurity phases were found;

[0079] c) 5-HEREA is a single RE3Al5O 12 The structure was intact, and no other impurities were found.

[0080] d) 5-HEREN has a single RENbO4 structure, and no other impurity phases were found;

[0081] e) 5-HERET has a single RETaO4 structure, and no other impurities were found.

[0082] 2) The high-entropy rare-earth oxide absorbing powders (5-HEREM, 5-HERED, 5-HEREZ, 5-HEREH, 5-HEREA, 5-HEREN, and 5-HERET) from Examples 1-7 were mixed with paraffin at a weight ratio of 7:3 at 100°C until homogeneous. The mixture was then processed into a coaxial ring with an inner diameter of 3 mm, an outer diameter of 7 mm, and a thickness of 2 mm. The absorption performance was then tested at a frequency range of 10 GHz to 18 GHz. The reflection loss test results are as follows: Figure 3 (a to g are 5-HEREM, 5-HERED, 5-HEREZ, 5-HEREH, 5-HEREA, 5-HEREN and 5-HERET respectively).

[0083] Depend on Figure 3 It can be known that:

[0084] a) The effective wave absorption bandwidth of 5-HEREM is 3.42 GHz, and the minimum reflection loss is -37.8 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0085] b) The effective wave absorption bandwidth of 5-HERED is 2.48 GHz, and the minimum reflection loss is -35.7 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0086] c) The effective wave absorption bandwidth of 5-HEREZ is 2.24 GHz, and the minimum reflection loss is -42.4 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0087] d) The effective wave absorption bandwidth of 5-HEREH is 4.36 GHz, and the minimum reflection loss is -40.2 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0088] e) The effective wave absorption bandwidth of 5-HEREA is 2.86 GHz, and the minimum reflection loss is -42.6 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0089] f) The effective wave absorption bandwidth of 5-HEREN is 1.82 GHz, and the minimum reflection loss is -37.4 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics;

[0090] g) The effective wave absorption bandwidth of 5-HERET is 1.82 GHz, and the minimum reflection loss is -47.2 dB, and the electromagnetic wave absorption performance is excellent, because: a large number of vacancy defects are generated by laser radiation heating, increasing the dipole polarization, and at the same time enhancing the conductance loss, finally endowing the high-entropy rare earth oxide with intrinsic wave absorption characteristics.

[0091] 3) The XRD patterns of the high-entropy rare earth oxide powders (Sample-1 and Sample-2) in Comparative Example 1 and Comparative Example 2 are as followsFigure 4 As shown.

[0092] By Figure 4 It can be seen that:

[0093] a) Sample-1 is a single RE2SiO5 structure, and no other impurities are found;

[0094] b) Sample-2 is a single RE2SiO5 structure, and no other impurities are found.

[0095] 4) The high-entropy rare earth oxide powder (Sample-1 and Sample-2) in the comparative example 1 and the comparative example 2 and the paraffin are mixed uniformly at a weight ratio of 7:3 at 100°C, and then processed into a coaxial ring with an inner diameter of 3mm, an outer diameter of 7mm and a thickness of 2mm, and then the wave absorption performance is tested, the test frequency range is 10GHz-18GHz, and the reflection loss test results are as shown in Figure 5 (a is Sample-1, b is Sample-2).

[0096] By Figure 5 It can be seen that:

[0097] a) The effective wave absorption bandwidth of Sample-1 is 0, that is, it does not have electromagnetic wave absorption performance at all, and the reason is that the vacancy defects generated by the muffle furnace calcination are very few;

[0098] b) The effective wave absorption bandwidth of Sample-2 is 0.26GHz, and the minimum reflection loss is-27.5dB, and the electromagnetic wave absorption performance is poor, and the reason is that the vacancy defects generated by the low-power laser synthesis are relatively few.

[0099] 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 and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.

Claims

1. A method for preparing a high-entropy rare earth oxide wave-absorbing powder, characterized in that, The method comprises the following steps: 1) mixing a rare earth oxide powder with one of SiO2 powder, ZrO2 powder, HfO2 powder, Al2O3 powder, Nb2O5 powder and Ta2O5 powder to obtain a mixed powder; 2) high-power laser radiation heating the mixed powder to obtain a high-entropy rare earth oxide wave-absorbing powder.

2. The method of claim 1, wherein: Step 1) the rare earth oxide powder is composed of at least four kinds of Sc2O3 powder, Y2O3 powder, La2O3 powder, CeO2 powder, Pr6O 11 powder, Nd2O3 powder, Sm2O3 powder, Eu2O3 powder, Gd2O3 powder, Tb4O7 powder, Dy2O3 powder, Ho2O3 powder, Er2O3 powder, Tm2O3 powder, Yb2O3 powder, and Lu2O3 powder in an equimolar ratio.

3. The production method according to claim 1 or 2, characterized by: In step 1), the particle size of the rare earth oxide powder, SiO2 powder, ZrO2 powder, HfO2 powder, Al2O3 powder, Nb2O5 powder and Ta2O5 powder is 1-3 μm, and the purity is greater than or equal to 99.9%.

4. The production method according to claim 1 or 2, characterized by: In step 1), the molar ratio of the rare earth oxide powder to SiO2 powder is 1:1.0-1.1 or 1:2.0-2.2; the molar ratio of the rare earth oxide powder to ZrO2 powder is 1:2.0-2.2; the molar ratio of the rare earth oxide powder to HfO2 powder is 1:2.0-2.2; the molar ratio of the rare earth oxide powder to Al2O3 powder is 1:1.0-1.1; the molar ratio of the rare earth oxide powder to Nb2O5 powder is 1:1.0-1.1; and the molar ratio of the rare earth oxide powder to Ta2O5 powder is 1:1.0-1.

1.

5. The production method according to claim 1 or 2, characterized by: In step 1), the mixing operation comprises wet ball milling, drying and grinding; the process parameters of 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 the powder raw material, ZrO2 balls and anhydrous ethanol is 1:1.8-2.2:1.0-1.5, and the ball milling time is 6-10 h; the drying is performed at a temperature of 80-100 ℃, and the drying time is 6-8 h.

6. The method of claim 1, wherein: In step 2), the mixed powder is placed in a graphite crucible and compacted before high-power laser radiation heating.

7. The method of claim 1 or 6, wherein: In step 2), the process parameters of the high-power laser radiation heating include: the laser power is 1000-1500 W, the duty cycle is 90%-100%, the heating temperature is 2800-3500 ℃, and the heating time is 2-5 s.

8. A high-entropy rare earth oxide wave-absorbing powder, characterized in that, The high-entropy rare earth oxide wave-absorbing powder prepared by the method of any one of claims 1-7.

9. A thermal protection stealth coating, characterized in that, The high-entropy rare earth oxide wave-absorbing powder of claim 8.

10. An aerospace engine, characterized by, The thermal protection stealth coating of claim 9 is coated on the surface of a hot end component.

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