Pyrophosphate-based high-entropy wave-absorbing ceramic powder material, preparation method and application

Abstract

The invention relates to the technical field of ceramic powder materials, in particular to a pyrophosphate-based high-entropy wave-absorbing ceramic powder material, a preparation method and application. The structural general formula of the ceramic powder material is [(TM1) x (TM2) y (TiZrHf) z] P2O7, and TM is any two of Cr, Fe, Mo and Nb; the preparation raw materials comprise titanium dioxide, zirconium dioxide, hafnium oxide, any two of molybdenum dioxide, niobium pentoxide, chromium sesquioxide and iron sesquioxide, and phosphoric acid. And uniformly mixing titanium dioxide, zirconium dioxide, hafnium oxide and any two of the other four transition metal oxides, mixing with excessive phosphoric acid, fully stirring, and calcining to obtain the pyrophosphate-based high-entropy ceramic powder material. The high-entropy ceramic powder material has the characteristics of high purity, good wave-absorbing performance and wide absorption frequency band, is simple in preparation method, is suitable for industrial production, and has an excellent application prospect in the field of wave-absorbing materials.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic powder materials, and particularly relates to a pyrophosphate-based high-entropy wave-absorbing ceramic powder material, a preparation method and an application thereof. Background Art

[0002] With the development of modern science and technology, various electronic and electrical devices have provided great help for people's daily life. However, at the same time, the electromagnetic radiation and interference problems generated by these devices have brought new problems to people's production and life, deteriorating the living space of humans. Therefore, it is necessary to develop wave-absorbing materials to absorb electromagnetic wave signals. An ideal wave-absorbing material should have the characteristics of "thin, light, wide, and strong". With the development of technology, future new-generation wave-absorbing materials are also required to have environmental adaptability, high temperature resistance, oxidation resistance, etc.

[0003] Currently, the mainly used wave-absorbing materials are magnetic metal materials, semiconductor materials, carbon-based and iron-based absorbers, etc. Some wave-absorbing materials of high-entropy carbides and borides have also been developed one after another. Comparative document 1 (Journal of Alloysand Compounds, 2023, 931: 167497.) reported a preparation method of a high electromagnetic wave-absorbing magnetite / coke composite material, and comparative document 2 (Applied Surface Science, 2023, 610: 155539.) reported a preparation method of a copper sulfide-based semiconductor with high electromagnetic wave absorption. Comparative document 3 (Materials Research Bulletin 2023, 163: 112212.) reported a preparation method of a high-entropy carbide wave-absorbing ceramic. However, the high electromagnetic wave-absorbing materials reported in the above documents have problems such as narrow absorption frequency band, single absorption frequency band, large density, and poor oxidation resistance, and there has been no report on the use of metal pyrophosphates as electromagnetic wave-absorbing materials.

[0004] Metal pyrophosphates not only have the characteristics of low density and good high-temperature stability, but also have large adjustable size of lattice accommodating metal atoms, with good performance regulation space, which is conducive to using the high-entropy effect to control their performance in a large range by adding different metals. In addition, these compounds also have low thermal conductivity and are expected to be developed into new multifunctional thermal protection materials for hypersonic aircraft. However, there is currently no research and report on the composition and electromagnetic absorption performance of high-entropy pyrophosphates. Summary of the Invention

[0005] The purpose of the present invention is to provide a pyrophosphate-based high-entropy wave-absorbing ceramic powder material, a preparation method and an application thereof, so as to solve the problems of narrow absorption frequency band, single absorption frequency band, large density and poor oxidation resistance of the existing wave-absorbing materials.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A pyrophosphate-based high-entropy microwave absorbing ceramic powder material, the structural general formula of the ceramic powder material is [(TM1) x (TM2) y (TiZrHf) z P2O7, and the general formula valence is zero; wherein, TM1 and TM2 are any two of Cr, Fe, Mo, and Nb.

[0007] Further, the preparation raw materials of the ceramic powder material include titanium dioxide powder, zirconium dioxide powder, hafnium dioxide powder, and any two of molybdenum dioxide powder, niobium pentoxide powder, chromium(III) oxide powder, and iron(III) oxide powder, and phosphoric acid.

[0008] Further, in terms of molar percentage, the proportions of each metal oxide powder component in the preparation raw materials are: 20 mol% - 35 mol% titanium dioxide, 20 mol% - 35 mol% zirconium dioxide, 20 mol% - 35 mol% hafnium dioxide, 20 mol% - 35 mol% molybdenum dioxide, 20 mol% - 35 mol% niobium pentoxide, 3 mol% - 10 mol% chromium(III) oxide, 3 mol% - 10 mol% iron(III) oxide; wherein the molar percentages of titanium dioxide, zirconium dioxide, and hafnium dioxide are equal; the total molar percentage of titanium dioxide, zirconium dioxide, hafnium dioxide, and any two of molybdenum dioxide, niobium pentoxide, chromium(III) oxide, and iron(III) oxide is 100 mol%; phosphoric acid is in excess, and the molar percentage of the amount of phosphoric acid used is 200 - 500 mol%.

[0009] Further, the particle size of each preparation raw material powder is 1 - 3 μm, and the purity is not less than 99%; the purity of phosphoric acid is not less than 85%.

[0010] A preparation method of a pyrophosphate-based high-entropy microwave absorbing ceramic powder material includes the following steps:

[0011] S1. Mix titanium dioxide, zirconium dioxide, hafnium dioxide, and any two of the above four other transition metal oxides in the presence of a mixing medium to obtain a uniformly mixed slurry;

[0012] S2. Filter, dry, and screen the uniformly mixed slurry obtained in S1 to obtain a mixed powder;

[0013] S3. Mix the mixed powder obtained in S2 with excess phosphoric acid and then calcine to obtain the pyrophosphate-based high-entropy ceramic powder material of the present invention.

[0014] Further, in the above-mentioned S1, each powder raw material is mixed in a ball milling tank. The ball milling medium is zirconia ball milling beads with a size of 5 - 10 mm. The mass ratio of the ball milling medium to the raw material powder is 5 - 10:1. The mixing medium is anhydrous ethanol, and the volume-mass ratio of the mixing medium to the raw material powder is 3 - 5:1. The ball milling intensity is 150 - 300 r / min, and the ball milling time is 6 - 12 h.

[0015] Further, in the above-mentioned S2, the drying temperature is 60 - 100 °C, and the drying time is 6 - 10 h. After drying, it is sieved through a 120 - 300 mesh sieve.

[0016] Further, in the above-mentioned S3, the calcination temperature is 1000 - 1600 °C, and the calcination time is 1 - 3 h.

[0017] Further, the maximum wave absorption loss of the pyrophosphate-based ceramic powder material is not less than 23.4 dB at a frequency of 2 - 18 GHz; when the reflectivity is below -10 dB, the maximum absorption frequency bandwidth is not less than 1.6 GHz.

[0018] Application of the pyrophosphate-based high-entropy wave-absorbing ceramic powder material in wave-absorbing coatings.

[0019] Advantages of the present invention:

[0020] 1. The present invention uses titanium dioxide, zirconium dioxide, hafnium dioxide, molybdenum dioxide, niobium pentoxide, chromium trioxide, iron(III) oxide, molybdenum dioxide, and phosphoric acid as raw materials, and obtains a pyrophosphate-based high-entropy wave-absorbing ceramic with high purity, strong wave absorption performance, and wide absorption frequency band through a muffle furnace. Analysis shows that the maximum wave absorption loss of the prepared pyrophosphate-based high-entropy wave-absorbing ceramic is not less than 23.4 dB; the maximum absorption frequency bandwidth is not less than 1.6 GHz.

[0021] 2. The preparation method of a pyrophosphate-based high-entropy wave-absorbing ceramic provided by the present invention is simple, fast, and highly practical. The prepared pyrophosphate-based high-entropy wave-absorbing ceramic has the advantages of high temperature resistance, high purity, strong wave absorption performance, and wide absorption frequency band. Description of the drawings

[0022] Figure 1 is the X-ray diffraction pattern of the ceramic powder material obtained in Example 1 of the present invention;

[0023] Figure 2 is the echo loss spectrum of the ceramic powder material obtained in Example 1 of the present invention;

[0024] Figure 3 is the microscopic structure photograph of the ceramic powder material obtained in Example 2 of the present invention;

[0025] Figure 4is a return loss spectrum of the ceramic powder material obtained in Example 3 of the present invention;

[0026] Figure 5 This is the return loss spectrum of the ceramic powder material obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] The raw materials of the embodiments of the present invention are from: TiO2 (Shanghai McLean Biochemical Technology Co., Ltd., purity 99%); ZrO2 (Qinhuangdao Yinuo High-tech Materials Development Co., Ltd., purity 99.9%); HfO2 (Qinhuangdao Yinuo High-tech Materials Development Co., Ltd., purity 99.99%); MoO2 (Shanghai Aladdin Biochemical Technology Co., Ltd., purity 99%); Nb2O5 (Shanghai McLean Biochemical Technology Co., Ltd., purity 99.9%); Cr2O3 (Beijing Huawei Ruike Chemical Co., Ltd., purity 99.9%); Fe2O3 (Shanghai McLean Biochemical Technology Co., Ltd., purity 99.9%); each metal oxide raw material is a powder with a particle size of 1-3μm; phosphoric acid (Tianjin Komio Chemical Reagent Co., Ltd., content ≥85.0%).

[0029] Example 1

[0030] TiO2, ZrO2, HfO2, Cr2O3, Fe2O3 and phosphoric acid are selected as raw materials, and 30.77mol% TiO2, 30.77mol% ZrO2, 30.77mol% HfO2, 3.85mol% Cr2O3 and 3.84mol% Fe2O3 are weighed in molar percentage. The raw material powders are mixed in a ball mill. The ball milling medium is zirconium dioxide ball milling beads with a size of 5 to 10mm. The mass ratio of the ball milling medium to the raw material powder is 8:1. The mixing medium is anhydrous ethanol, and the volume mass ratio of the mixing medium to the raw material powder is 4:1. The ball milling intensity is 200r / min, and the ball milling time is 10h. A mixed slurry is obtained.

[0031] The obtained mixed slurry was filtered and dried at a temperature of 70°C for 8 hours; after drying, it was sieved through a 300-mesh sieve; the sieved powder was mixed with phosphoric acid at a molar ratio of 1:3, stirred at a speed of 50 r / min for 2 hours using a magnetic stirrer, and after being fully mixed, it was placed in a muffle furnace for calcination at a temperature of 1400°C for 1 hour to obtain a pyrophosphate-based high-entropy absorbing ceramic powder.

[0032] The purity of the ceramic powder material is 100 wt%, the average particle size is 1.4 microns, the maximum wave absorption loss measured using an Agilent N5244A vector network analyzer at a frequency of 2 - 18 GHz is 23.4 dB, and the maximum absorption frequency bandwidth is 2.5 GHz when the reflectivity is below -10 dB. The composition of the obtained high-entropy ceramic powder material is as Figure 1 shown in the X-ray diffraction pattern, and the wave absorption loss of the high-entropy ceramic powder material at a frequency of 2 - 18 GHz is as Figure 2 shown in the echo loss spectrum. It shows that when the high-temperature reaction temperature is 1400 °C, a pyrophosphate-based high-entropy wave-absorbing ceramic powder material with a purity of not less than 99 wt% can be prepared.

[0033] Example 2

[0034] This example is the same as Example 1, except that: using TiO2, ZrO2, HfO2, MoO2, Nb2O5 as raw materials, and weighing 20 mol% TiO2, 20 mol% ZrO2, 20 mol% HfO2, 20 mol% MoO2, 20 mol% Nb2O5 in terms of molar percentage.

[0035] The calcination temperature is 1500 °C and the calcination time is 2 h. The purity of the obtained high-entropy ceramic powder material is 100 wt%, the average particle size is 1.8 microns, the wave absorption loss at a frequency of 2 - 18 GHz is 53.1 dB, and the maximum absorption frequency bandwidth is 2.4 GHz when the reflectivity is below -10 dB. The microscopic morphology of the obtained high-entropy ceramic powder material is as Figure 3 shown.

[0036] Example 3

[0037] This example is the same as Example 1 and Example 2, except that: using TiO2, ZrO2, HfO2, MoO2, Fe2O3 as raw materials, and weighing 24.24 mol% TiO2, 24.24 mol% ZrO2, 24.24 mol% HfO2, 24.24 mol% MoO2, 3.04 mol% Fe2O3 in terms of molar percentage.

[0038] The calcination temperature is 1200 °C and the calcination time is 1 h. The purity of the obtained high-entropy ceramic powder material is 100 wt%, the average particle size is 2.1 microns, the wave absorption loss at a frequency of 2 - 18 GHz is 44.8 dB, and the maximum absorption frequency bandwidth is 1.76 GHz when the reflectivity is below -10 dB. The wave absorption loss of the high-entropy ceramic powder material at a frequency of 2 - 18 GHz is as Figure 4 shown in the echo loss spectrum.

[0039] Example 4

[0040] This example is consistent with Example 1, Example 2, and Example 3, with the only difference being that TiO2, ZrO2, HfO2, MoO2, and Cr2O3 are used as raw materials. By molar percentage, 24.24 mol% TiO2, 24.24 mol% ZrO2, 24.24 mol% HfO2, 24.24 mol% MoO2, and 3.04 mol% Cr2O3 are weighed out.

[0041] The calcination temperature is 1500 °C and the calcination time is 2 h. The purity of the obtained high-entropy ceramic powder material is 100 wt%, the average particle size is 2.5 microns, the microwave absorption loss at a frequency of 2 - 18 GHz is 40.9 dB, and the maximum absorption bandwidth is 1.6 GHz when the reflectivity is below -10 dB. The microwave absorption loss of the high-entropy ceramic powder material at a frequency of 2 - 18 GHz is as Figure 5 shown in the echo loss spectrum diagram.

[0042] The present invention is not limited to the above optimal implementation manner. Any person can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as it has a technical solution that is the same as or similar to the present application, it falls within the protection scope of the present invention.

Claims

1. A pyrophosphate-based high entropy microwave absorbing ceramic powder material, characterized in that: The general structural formula of the ceramic powder material is [(TM1) x (TM2) y (TiZrHf) z ]P2O7, the general valence is zero; among them, TM1 and TM2 are any two of Cr, Fe, Mo, and Nb.

2. The pyrophosphate-based high entropy microwave absorbing ceramic powder material according to claim 1, characterized in that: The raw materials for preparing the ceramic powder material include titanium dioxide powder, zirconium dioxide powder, hafnium dioxide powder, any two of molybdenum dioxide powder, niobium pentoxide powder, chromium trioxide powder and iron trioxide powder, and phosphoric acid.

3. The pyrophosphate-based high entropy microwave absorbing ceramic powder material, preparation method and application according to claim 2, characterized in that: In terms of molar percentage, the proportions of the metal oxide powder components in the preparation raw materials are: 20mol% to 35mol% titanium dioxide, 20mol% to 35mol% zirconium dioxide, 20mol% to 35mol% hafnium dioxide, 20mol% to 35mol% molybdenum dioxide, 20mol% to 35mol% niobium pentoxide, 3mol% to 10mol% chromium trioxide, and 3mol% to 10mol% iron trioxide; wherein the molar percentages of titanium dioxide, zirconium dioxide, and hafnium dioxide are equal; the total molar percentage of titanium dioxide, zirconium dioxide, hafnium dioxide, and any two of molybdenum dioxide, niobium pentoxide, chromium trioxide, and iron trioxide is 100mol%; phosphoric acid is in excess, and the molar percentage of phosphoric acid used is 200 to 500mol%.

4. The pyrophosphate-based high entropy microwave absorbing ceramic powder material according to claim 2, characterized in that: The particle size of each raw material powder is 1-3 μm, and the purity is not less than 99%; the purity of phosphoric acid is not less than 85%.

5. The method for preparing the pyrophosphate-based high entropy microwave absorbing ceramic powder material according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Mix titanium dioxide, zirconium dioxide, hafnium dioxide and any two of the other four transition metal oxides in a medium to obtain a mixed slurry; S2, filtering, drying and sieving the mixed slurry obtained in S1 to obtain a mixed powder; S3, the mixed powder of S2 is mixed with excess phosphoric acid and then calcined to obtain the pyrophosphate-based high entropy ceramic powder material of the present invention.

6. The method for preparing the pyrophosphate-based high entropy microwave absorbing ceramic powder material according to claim 5, characterized in that: In the S1, the powder raw materials are mixed in a ball mill, the ball milling medium is zirconium dioxide ball milling beads with a size of 5 to 10 mm; the mass ratio of the ball milling medium to the raw material powder is 5 to 10:1; the mixing medium is anhydrous ethanol, and the volume mass ratio of the mixing medium to the raw material powder is 3 to 5:1; the ball milling intensity is 150 to 300 r / min; and the ball milling time is 6 to 12 h.

7. The method for preparing the pyrophosphate-based high entropy microwave absorbing ceramic powder material according to claim 5, characterized in that: In the S2, the drying temperature is 60-100° C., the drying time is 6-10 hours, and after drying, the product is sieved through a 120-300 mesh sieve.

8. The method for preparing the pyrophosphate-based high entropy microwave absorbing ceramic powder material according to claim 5, characterized in that: In the step S3, the calcination temperature is 1000-1600° C. and the calcination time is 1-3 hours.

9. The method for preparing the pyrophosphate-based high entropy microwave absorbing ceramic powder material according to any one of claims 5 to 8, characterized in that: The maximum wave absorption loss of the pyrophosphate-based ceramic powder material at a frequency of 2-18 GHz is not less than 23.4 dB; and the maximum absorption bandwidth is not less than 1.6 GHz when the reflectivity is below -10 dB.

10. Use of the pyrophosphate-based high entropy microwave-absorbing ceramic powder material according to any one of claims 1 to 9 in microwave-absorbing coatings.

Images