A CrNbRuNi microwave absorbing material and its preparation method

Abstract

This invention provides a CrNbRuNi microwave absorbing material and its preparation method, relating to the field of microwave absorbing materials technology. The CrNbRuNi microwave absorbing material has the chemical formula Cr2NbRu2-xNix, where 0≤x≤0.3. This composition of microwave absorbing material can absorb electromagnetic waves in the 2–18 GHz microwave band, with a wide effective absorption bandwidth and high absorption efficiency (>90%). The material also exhibits excellent thermal stability. Furthermore, this invention provides a method for preparing the aforementioned CrNbRuNi microwave absorbing material. The material can be obtained through arc melting, heat treatment, and ball milling. The synthesis process is simple and suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing materials technology, specifically to a CrNbRuNi microwave absorbing material and its preparation method. Technical Background

[0002] With the advent of the electronic information age, while various electronic devices have brought high efficiency to social production and great convenience to people's daily lives, the electromagnetic radiation they generate has also had very harmful effects on normal communication and human health. Studies have shown that electromagnetic radiation can reduce vision, damage nerves, interfere with the endocrine system, affect the cardiovascular system, attack the immune system, and may even lead to cancer.

[0003] To address the aforementioned issues, the research and development of electromagnetic wave absorbing materials with excellent absorption capabilities has become a current research hotspot. Electromagnetic wave absorbing materials can convert electromagnetic waves radiated onto a material's surface into heat energy and other energy losses, thereby reducing electromagnetic interference. High-quality electromagnetic wave absorbing materials should simultaneously possess the ability to absorb electromagnetic waves over a wide frequency range, and should also be as lightweight and corrosion-resistant as possible.

[0004] Current research on microwave absorbing materials mainly focuses on ferrites and magnetic metals. Ferrites are ferromagnetic materials, but their saturation magnetization and Curie temperature are relatively low. Magnetic metal microwave absorbing materials have strong conductivity, and their magnetic loss and dielectric loss are both greater than those of ferrites. Compared with ferrites, magnetic metal absorbers have advantages such as high saturation magnetization, high permeability, strong electromagnetic wave attenuation ability, and simple fabrication process. Therefore, magnetic metals hold promise as a microwave absorbing material with strong absorption capabilities.

[0005] By adjusting the morphology and crystal structure of sheet-like metal powders, the microwave electromagnetic parameters of composite materials can be modified to achieve better absorption effects and meet the requirements of wide effective absorption bandwidth, thin thickness, strong absorption performance, and light weight. Transition metal elements such as Fe, Co, and Ni possess excellent electrical conductivity, magnetic properties, high Curie temperatures, and good thermal stability. Therefore, utilizing the characteristics of transition metal elements to adjust and optimize the electromagnetic parameters of microwave absorbing materials can significantly improve absorption performance. Developing high-performance, low-cost magnetic microwave absorbing metal materials is of great significance to my country's communications field, public health, and national security. However, the absorption bandwidth of existing magnetic metal microwave absorbing materials is relatively narrow, and the absorption efficiency needs to be improved. Summary of the Invention

[0006] This invention provides a CrNbRuNi microwave absorbing material and its preparation method. The microwave absorbing material has a wide absorption bandwidth, high absorption efficiency, good thermal stability and oxidation resistance.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A CrNbRuNi microwave absorbing material with the molecular formula Cr2NbRu 2-x Ni x , where 0≤x≤0.3.

[0009] The preferred molecular formula of the CrNbRuNi microwave absorbing material is Cr2NbRu. 1.7 Ni 0.3 .

[0010] A method for preparing a CrNbRuNi microwave absorbing material includes the following steps:

[0011] (1) Weigh chromium, niobium, ruthenium and nickel in proportion and perform arc melting in a non-consumable vacuum arc furnace to obtain metal ingots for later use;

[0012] (2) The above metal ingots are heat-treated and then coarsely crushed in a grinding bowl to obtain metal powder;

[0013] (3) The above metal powder was ball-milled to obtain CrNbRuNi microwave absorbing material.

[0014] Preferably, the metallic chromium, niobium, ruthenium, and nickel are elemental metals, and the purity of the metallic chromium, niobium, ruthenium, and nickel is preferably 99.9%, more preferably 99.99%.

[0015] Preferably, the vacuum degree during the melting process is less than 3 × 10⁻⁶. -3 Pa.

[0016] Preferably, the metal ingot is repeatedly turned and melted 3-4 times during the smelting process.

[0017] Preferably, the melting loss rate of the smelted metal ingot is less than 1 wt.%.

[0018] The heat treatment temperature is preferably 1100℃, and the time is preferably 5-8 days, more preferably 7 days, after which a metal ingot is obtained.

[0019] Preferably, before heat treatment, the metal ingot is sealed in a tube, and the working vacuum degree of the sealing tube is preferably 1 to 5 × 10⁻⁶. -1 Pa, more preferably 1 to 2 × 10 Pa -1 Pa, the optimal value is 1×10 -1 Pa.

[0020] Preferably, the coarsely crushed powder passes through a 100-mesh sieve.

[0021] The preferred mass ratio of the coarsely crushed powder to the zirconia balls before ball milling is 10–16:1, more preferably 14–15:1, and most preferably 15:1.

[0022] Preferably, the mass ratio of the weighed zirconia balls is Φ8:Φ5:Φ3 = 2:5:3.

[0023] Preferably, the ball milling speed in step (3) is 200-250 r / min, and more preferably 250 r / min.

[0024] Preferably, the ball milling time in step (3) is 24 hours.

[0025] This invention provides a CrNbRuNi microwave absorbing material and its preparation method, which has the following advantages compared with the prior art:

[0026] (1) The alloy powder prepared by this invention is rich in a large number of thin-film structures, which greatly extends the reflection path of electromagnetic waves and is beneficial for attenuation. The thin-film structure easily forms a conductive network, increasing the conductivity loss. Secondly, due to the defects of complex structure and multiple relaxation polarization, the electromagnetic wave attenuation capability is increased. Thirdly, natural resonance and exchange resonance jointly deplete electromagnetic waves at the resonant frequency. Finally, better impedance matching performance can be obtained, and better microwave absorption performance can be obtained in the corresponding frequency band.

[0027] Doping causes Ni atoms to replace Ru atoms in the original unit cell, disrupting the long-range order and symmetry of the original unit cell, thus introducing defects or distortions and generating defect polarization. On the other hand, Ni doping reduces grain size while generating numerous thin, lamellar particles, which facilitate the formation of conductive networks, thereby reducing the resistivity of the material and improving its electrical loss capability. As the doping concentration increases, the conductivity of the alloy powder increases; the larger the generated current, the stronger the electrical loss capability. Therefore, Ni replaces the expensive Ru element while improving the microwave absorption performance of the material.

[0028] Doping with Ni can significantly alter the magnetocrystalline anisotropy field and diffusion activation energy of magnetic metallic microwave absorbing materials. This increases both the natural resonance absorption peak and the domain wall resonance absorption peak, resulting in a wider absorption bandwidth. The Ni-doped microwave absorbing materials can absorb electromagnetic waves in the 2-18 GHz microwave band with high absorption efficiency (>90%), and exhibit good thermal stability.

[0029] (2) The present invention provides a method for preparing the CrNbRuNi microwave absorbing material. The microwave absorbing material can be obtained by melting, heat treatment and ball milling. The preparation process is simple and suitable for large-scale production. Attached image description:

[0030] Figure 1 The reflectivity loss diagrams of the CrNbRuNi microwave absorbing materials prepared in Examples 1-4 and Comparative Example 1 of this invention are shown when the thickness is 1.6 mm.

[0031] Figure 2 The image shows the reflectivity loss of the Cr2NbRu2 microwave absorbing material prepared in Comparative Example 1 of this invention at different simulated thicknesses.

[0032] Figure 3 Cr2NbRu prepared in Example 1 of this invention 1.9 Ni 0.1 Reflectance loss of absorbing material at different simulated thicknesses;

[0033] Figure 4 Cr2NbRu prepared in Example 2 of this invention 1.8 Ni 0.2 Reflectance loss of absorbing material at different simulated thicknesses;

[0034] Figure 5 Cr2NbRu prepared in Example 3 of this invention 1.7 Ni 0.3 Reflectivity loss diagram of absorbing material at different simulated thicknesses. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Example 1:

[0037] Preparation of Cr2NbRu 1.9 Ni 0.1 Magnetic absorbing materials:

[0038] (1) According to the chemical formula Cr2NbRu 1.9 Ni 0.1 Weigh out 0.9126g of metallic chromium (99.99% purity), 0.5436g of niobium, 1.4980g of ruthenium, and 0.0457g of nickel, and place them in a non-consumable vacuum melting furnace for melting. When the furnace vacuum reaches 3.0 × 10⁻⁶ mm, the melting process is complete. -3 After Pa, argon gas is introduced for protection, and the melting current is 80-90A. The melting is repeated 4 times to obtain a metal ingot.

[0039] (2) The metal ingot is placed in a quartz tube and vacuumed, then the tube is sealed. The sealed sample is placed in a muffle furnace and heat-treated at 1100°C for 7 days to obtain the heat-treated metal ingot.

[0040] (3) The heat-treated metal ingot is coarsely crushed and ground until it can pass through a 100-mesh sieve. The sieved powder and zirconia balls are weighed at a mass ratio of 20:1 and placed in a ball mill jar. The mass ratio of the zirconia balls is Φ8:Φ5:Φ3=2:5:3. Anhydrous ethanol is added until the zirconia balls are submerged by 2-3 cm. The mixture is ball-milled at 250 r / min for 24 h. The resulting alloy microwave absorbing material is denoted as Cr2NbRu. 1.9 Ni 0.1 .

[0041] Example 2:

[0042] Preparation of Cr2NbRu 1.8 Ni 0.2 Magnetic absorbing materials

[0043] (1) According to the chemical formula Cr2NbRu 1.8 Ni 0.2 Weigh out 0.9228g of chromium (99.99% purity), 0.5495g of niobium, 1.4344g of ruthenium, and 0.0926g of nickel. Place the metals in a non-consumable vacuum melting furnace for melting. When the furnace vacuum reaches 3.0 × 10⁻⁶ mm, the metals are melted. -3 After Pa, argon gas is introduced for protection, and the melting current is 80-90A. The melting is repeated 4 times to obtain a metal ingot.

[0044] (2) The metal ingot is placed in a quartz tube and vacuumed, then the tube is sealed. The sealed sample is placed in a muffle furnace and heat-treated at 1100°C for 7 days to obtain the heat-treated metal ingot.

[0045] (3) The heat-treated metal ingot is coarsely crushed and ground until it can pass through a 100-mesh sieve. The sieved powder and zirconia balls are weighed at a mass ratio of 20:1 and placed in a ball mill jar. The mass ratio of the zirconia balls is Φ8:Φ5:Φ3=2:5:3. Anhydrous ethanol is added until the zirconia balls are submerged by 2-3 cm. The mixture is ball-milled at 250 r / min for 24 h. The resulting alloy microwave absorbing material is denoted as Cr2NbRu. 1.8 Ni 0.2 .

[0046] Example 3:

[0047] Preparation of Cr2NbRu 1.7 Ni 0.3 Magnetic absorbing materials

[0048] (1) According to the chemical formula Cr2NbRu 1.7 Ni 0.3 Weigh out 0.9333g of chromium (99.99% purity), 0.5560g of niobium, 1.3705g of ruthenium, and 0.1405g of nickel. Place the metals in a non-consumable vacuum melting furnace for melting. When the furnace vacuum reaches 3.0 × 10⁻⁶ mm, the metals are melted. - 3 After Pa, argon gas is introduced for protection, and the melting current is 80-90A. The melting is repeated 4 times to obtain a metal ingot.

[0049] (2) The metal ingot is placed in a quartz tube and vacuumed, then the tube is sealed. The sealed sample is placed in a muffle furnace and heat-treated at 1100°C for 7 days to obtain the heat-treated metal ingot.

[0050] (3) The heat-treated metal ingot is coarsely crushed and ground until it can pass through a 100-mesh sieve. The sieved powder and zirconia balls are weighed at a mass ratio of 15:1 and placed in a ball mill jar. The mass ratio of the zirconia balls is Φ8:Φ5:Φ3 = 2:5:3. Anhydrous ethanol is added until the zirconia balls are submerged by 2-3 cm. The mixture is ball-milled at 250 r / min for 24 h. The resulting alloy microwave absorbing material is denoted as Cr2NbRu. 1.7 Ni 0.3 .

[0051] Comparative Example 1:

[0052] Preparation of Cr2NbRu2 magnetic microwave absorbing materials

[0053] (1) Weigh out 0.9026g of chromium (99.99% purity), 0.5384g of niobium, and 1.5605g of ruthenium according to the chemical formula Cr2NbRu2. Place the metals in a non-consumable vacuum melting furnace for melting. When the vacuum in the furnace reaches 3.0×10⁻⁶ mm, the metals are melted. -3 After Pa, argon gas is introduced for protection, and the melting current is 80-90A. The melting is repeated 4 times to obtain a metal ingot.

[0054] (2) The metal ingot is placed in a quartz tube and vacuumed, then the tube is sealed. The sealed sample is placed in a muffle furnace and heat-treated at 1100°C for 7 days to obtain the heat-treated metal ingot.

[0055] (3) The heat-treated metal ingot is coarsely crushed and ground until it can pass through a 100-mesh sieve. The sieved powder is weighed with zirconia balls at a mass ratio of 20:1 and placed in a ball mill jar. The mass ratio of the zirconia balls is Φ8:Φ5:Φ3=2:5:3. Anhydrous ethanol is added until the zirconia balls are submerged by 2-3 cm. The mixture is ball-milled at 250 r / min for 24 h. The resulting alloy microwave absorbing material is denoted as Cr2NbRu2.

[0056] Performance testing

[0057] 1. The reflectivity of the alloy absorbing materials prepared in Examples 1-4 and Comparative Example 1 was measured:

[0058] Measurement method: A coaxial sample with an outer diameter of 7 mm and an inner diameter of 3 mm, and a thickness of 3.0–3.2 mm, was prepared by mixing powder (alloy absorbing material) and paraffin wax in a mass ratio of 3:1. The complex permeability and complex permittivity of the sample were measured in the 2–18 GHz frequency band using an Agilent 8720ET microwave vector network analyzer. The reflectivity R of the single-layer absorbing material was then calculated using the following formula:

[0059]

[0060] In the formula, ε r μ r d and d represent the relative permittivity, relative permeability, and thickness of the absorbing material, respectively; f is the frequency of the electromagnetic wave; c is the propagation speed of the electromagnetic wave in a vacuum (i.e., the speed of light); and j is the imaginary unit.

[0061] When testing the reflectivity of the alloy absorbing materials prepared in Examples 1-3 and Comparative Example 1:

[0062] A. For the Cr2NbRu2 prepared in Comparative Example 1, the reflectivity R was calculated for simulated monolayer absorbing material with thicknesses of 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm, as shown below. Figure 2 As shown:

[0063] As can be seen from the figure, the minimum reflectivity peak values ​​of thicknesses of 1.6mm, 1.8mm, and 2.0mm are all less than -10dB (absorption rate is greater than 90%), and the bandwidth of R<-10dB is relatively wide, which has a certain broadband effect. When the material thickness is 1.6 mm, its bandwidth with R < -10 dB is approximately 1.2 GHz, and its minimum reflectivity peak at 15.84 GHz is approximately -13.88 dB (absorption rate approximately 95.91%). When the material thickness is 1.8 mm, its bandwidth with R < -10 dB is approximately 1.76 GHz, and its minimum reflectivity peak at 14.8 GHz is approximately -31.20 dB (absorption rate approximately 99.92%). When the material thickness is 2.0 mm, its bandwidth with R < -10 dB is approximately 1.28 GHz, and its minimum reflectivity peak at 14.72 GHz is approximately -12.58 dB (absorption rate approximately 94.48%). Therefore, Cr2NbRu2 has certain microwave absorption properties.

[0064] B. For the Cr2NbRu prepared in Example 1 1.9 Ni 0.1The results of calculating the reflectivity R of the simulated single-layer absorbing material with thicknesses of 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm are as follows: Figure 3 As shown:

[0065] As shown in the figure, for all thicknesses, the minimum reflectivity peak is less than -10dB (absorption rate greater than 90%), and the bandwidth with R < -10dB is relatively wide, exhibiting a certain broadband effect. When the material thickness is 1.4mm, its bandwidth with R < -10dB is approximately 1.2GHz, and at 12.88GHz, its maximum reflectivity is approximately -27.69dB (absorption rate approximately 99.83%); when the thickness is 1.6mm, its bandwidth with R < -10dB is approximately 0.72GHz, and at 10.72GHz, its maximum reflectivity is approximately -14.29dB (absorption rate approximately 96.28%); when... When the material thickness is 1.8 mm, its bandwidth with R < -10 dB is approximately 1.44 GHz, and its minimum reflectivity peak at 10.64 GHz is approximately -44.40 dB (absorption rate approximately 99.99%). When the material thickness is 2.0 mm, its bandwidth with R < -10 dB is approximately 1.84 GHz, and its minimum reflectivity peak at 10.72 GHz is approximately -15.29 dB (absorption rate approximately 97.04%).

[0066] C. For the Cr2NbRu prepared in Example 2 1.8 Ni 0.2 The results of the calculated and simulated reflectivity R for single-layer absorbing material with thicknesses of 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm are as follows: Figure 4 As shown:

[0067] As can be seen from the figure, the minimum reflectivity peak value is less than -10dB (absorption rate is greater than 90%) for all thicknesses, and the bandwidth of R<-10dB is relatively wide, which has a certain broadband effect. When the material thickness is 1.4 mm, its bandwidth with R < -10 dB is approximately 2.24 GHz, and its maximum reflectivity at 12 GHz is approximately -24.38 dB (absorption rate approximately 99.64%). When the thickness is 1.6 mm, its bandwidth with R < -10 dB is approximately 0.56 GHz, and its maximum reflectivity at 10 GHz is approximately -10.98 dB (absorption rate approximately 92.02%). When the material thickness is 1.8 mm, its bandwidth with R < -10 dB is approximately 1.68 GHz, and its minimum peak reflectivity at 9.12 GHz is approximately -14.51 dB (absorption rate approximately 96.46%). When the material thickness is 2.0 mm, its bandwidth with R < -10 dB is approximately 2.16 GHz, and its minimum peak reflectivity at 8.72 GHz is approximately -31.94 dB (absorption rate approximately 99.94%).

[0068] D. Regarding the Cr2NbRu prepared in Example 3 1.7 Ni 0.3 The results of the calculated and simulated reflectivity R for single-layer absorbing material thicknesses of 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm are as follows: Figure 5 As shown:

[0069] As can be seen from the figure, the minimum reflectivity peak value is less than -10dB (absorption rate is greater than 90%) for all thicknesses, and the bandwidth of R<-10dB is relatively wide, which has a certain broadband effect. When the material thickness is 1.4 mm, its bandwidth with R < -10 dB is approximately 2 GHz, and its maximum reflectivity at 11.12 GHz is approximately -15.66 dB (absorption rate approximately 97.28%). When the thickness is 1.6 mm, its bandwidth with R < -10 dB is approximately 1.28 GHz, and its maximum reflectivity at 10 GHz is approximately -46.10 dB (absorption rate approximately 99.99%). When the material thickness is 1.8 mm, its bandwidth with R < -10 dB is approximately 0.56 GHz, and its minimum peak reflectivity at 9.76 GHz is approximately -13.59 dB (absorption rate approximately 95.62%). When the material thickness is 2.0 mm, its bandwidth with R < -10 dB is approximately 0.72 GHz, and its minimum peak reflectivity at 7.52 GHz is approximately -18.78 dB (absorption rate approximately 98.68%).

[0070] E. Test the reflectivity loss of the absorbing materials prepared in Examples 1-3 and Comparative Example 1 at a thickness of 1.6 mm:

[0071] The results are as follows Figure 1 As shown, the minimum reflectivity peak of the CrNbRuNi material shifts to the lower frequency region after Ni addition. The peak reflectivity increases with increasing Ni content, and the minimum reflectivity peak is less than -10 dB (absorption rate greater than 90%) when Ni content is 0, 0.1, 0.2, and 0.3%. When Ni content is 0, 0.1, 0.2, and 0.3, the frequencies at which the powder exhibits reflectivity loss resonance peaks are 15.84 GHz, 10.72 GHz, 10 GHz, and 10 GHz, respectively, with corresponding reflectivity peaks of -13.88 dB, -14.29 dB, -10.98 dB, and -46.10 dB. The effective bandwidths of R < -10 dB are 1.2 GHz, 0.72 GHz, 0.56 GHz, and 1.28 GHz, respectively. These data indicate that the powder has a certain absorption bandwidth and absorption performance in the 2–18 GHz frequency band.

[0072] As can be seen from Examples 1-3 and Comparative Example 1, the present invention, by adding an appropriate amount of Ni element to CrNbRu material, improves the chemical formula Cr2NbRu.1.7 Ni 0.3 The alloy with added Ni showed a significant improvement in its minimum reflectivity peak value, which increased from -13.88dB to -46.10dB. The bandwidth was widened from 1.2GHz to 1.28GHz, and the peak position was moved from 15.84GHz to 10GHz. The minimum reflectivity peak value, corresponding frequency, and effective bandwidth after adding Ni are shown in Table 1.

[0073] Table 1. Ni 45-x Si 49.6 Al 5.4 Gd x Wave absorption performance of (x=0,2,4,6,8) at d=2mm

[0074]

[0075] As can be seen from the above embodiments, the present invention provides a CrNbRuNi microwave absorbing material that can absorb electromagnetic waves in the 2-18 GHz microwave band, with a wide absorption bandwidth and high absorption efficiency (>90%). Furthermore, the alloy has a high heat treatment temperature and exhibits certain thermal stability. In addition, due to its low density, this material meets the requirement of lightweight microwave absorbing materials. The present invention also provides a method for preparing the CrNbRuNi microwave absorbing material, which can be obtained through melting, heat treatment, and ball milling. The preparation process is simple and suitable for large-scale production.

[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A CrNbRuNi wave-absorbing material, characterized in that, The chemical formula of the CrNbRuNi microwave absorbing material is Cr2NbRu2-xNix, where 0 < x ≤ 0.3; and the CrNbRuNi microwave absorbing material is prepared by a preparation method including the following steps: (1) weighing metals chromium, niobium, ruthenium and nickel in proportion, and performing arc melting in a non-consumable vacuum arc furnace to obtain a metal ingot for standby; (2) performing heat treatment on the above metal ingot, the heat treatment temperature is 1100 °C, the heat treatment time is 7 days, and then performing coarse crushing in a mortar to obtain metal powder; (3) ball-milling the above metal powder to obtain the CrNbRuNi microwave absorbing material.

2. The preparation method of the CrNbRuNi wave-absorbing material according to claim 1, characterized in that, Including the following steps: (1) Weigh metals chromium, niobium, ruthenium and nickel in proportion, and perform arc melting in a non-consumable vacuum arc furnace to obtain a metal ingot for standby; (2) Perform heat treatment on the above metal ingot, and then perform coarse crushing to obtain metal powder; (3) Ball-mill the above metal powder to obtain the CrNbRuNi microwave absorbing material.

3. The preparation method of the CrNbRuNi wave-absorbing material according to claim 2, characterized in that: The purity of the metals chromium, niobium, ruthenium and nickel is equal to or greater than 99.9%.

4. The preparation method of the CrNbRuNi wave-absorbing material according to claim 2, characterized in that: The melting loss rate of the melted metal ingot is less than 1 wt.%.

5. The preparation method of the CrNbRuNi wave-absorbing material according to claim 2, characterized in that: The metal ingot for coarse crushing in step (2) is ground in a mortar.

6. The preparation method of the CrNbRuNi wave-absorbing material according to claim 2, characterized in that: The metal powder after coarse crushing in step (2) is poured into an agate mortar for grinding and sieved through a 100-mesh sieve.

7. The preparation method of the CrNbRuNi wave-absorbing material according to claim 2, characterized in that: In step (3), the rotation speed of ball milling is 200 - 300 r / min, and the ball milling time is 24 h.

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