A cobalt-based hasler alloy material, a preparation method and application thereof

Abstract

This invention discloses a cobalt-based Hassler alloy material, its preparation method, and its application. The preparation method includes the following steps: (1) Weighing cobalt powder, iron powder, and germanium powder in a molar ratio of 2:(1~1.75):(0.25~1), mixing them, placing them in a tungsten carbide grinding jar, adding anhydrous ethanol, adding grinding balls, and ball milling; (2) Drying and sieving the ball-milled powder, taking the sieved magnetic alloy powder, sealing it in a vacuum quartz tube, heat-treating it using a muffle furnace, and cooling it to room temperature with the furnace to obtain a cobalt-iron-germanium Hassler alloy. This invention uses a ball milling method, which can effectively change the surface morphology of the alloy powder, making it form a flake powder with a larger specific surface area, thereby improving the electromagnetic absorption performance of the magnetic alloy; by selecting and changing the proportion of the Hassler alloy components, the saturation magnetization of the magnetic alloy can be effectively increased, its Curie temperature can be increased, and the electromagnetic wave absorption performance of the magnetic alloy at high temperatures can be improved.

Description

Technical Field

[0001] This application relates to the field of magnetic materials technology, and in particular to a cobalt-based Hassler alloy material, its preparation method, and its application. Background Technology

[0002] With the development of science and technology, electromagnetic wave technology and its applications have penetrated all aspects of human society, finding wide application in fields such as wireless communication, biological detection and treatment, and military defense. However, the resulting electromagnetic pollution has also caused significant harm to human health and the ecological environment. Therefore, electromagnetic wave shielding and absorbing materials have attracted widespread interest from researchers, including nanomaterials, composite materials, and metallic materials. Fe, Co, and Ni-based alloys typically possess high saturation magnetization and permeability, showing great potential as electromagnetic wave absorbing materials. However, these alloys often suffer from disadvantages such as insufficient corrosion resistance, oxidation resistance, and high-temperature stability.

[0003] In 1903, an alloy composed of non-ferromagnetic elements Cu, Mn, and Al exhibited ferromagnetism and was named Heusler alloy. Today, Heusler alloys have been extensively studied and applied. The reason for this ferromagnetism has been revealed, but their applications continue to expand. Heusler alloys can form two structures: full Heusler and half Heusler, described as XYZ and X2YZ respectively, where X and Y are transition elements and Z is a main group element. Due to their unique structure, these alloys typically possess good corrosion resistance, high-temperature stability, and high saturation magnetization, thus showing broad application prospects in fields such as spintronic devices and electromagnetic wave absorption and protection.

[0004] In the field of military warfare, radar-absorbing materials can effectively reduce the radar detection characteristics of high-value equipment and facilities such as fighter jets, warships and non-combat vehicles. However, the high-temperature stability and high magnetic saturation strength of traditional carbon-based radar-absorbing materials still cannot meet the requirements.

[0005] Therefore, how to prepare a Heusler alloy with better high-temperature thermal stability and saturation magnetization is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a cobalt-based Hassler alloy material with strong absorption and high temperature stability, a method for manufacturing the same, and the application of the alloy material in electromagnetic absorption.

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

[0008] A method for preparing a cobalt-based Hassler alloy material includes the following steps:

[0009] (1) Weigh cobalt powder, iron powder and germanium powder in a molar ratio of 2:(1~1.75):(0.25~1), mix them into a mixed raw material powder, place it in a tungsten carbide grinding jar, add anhydrous ethanol as a process control agent, add grinding balls, and ball mill.

[0010] (2) The ball milled powder obtained in step 1 is dried and sieved. The magnetic alloy powder under the sieve is sealed into a vacuum quartz tube and heat-treated in a muffle furnace. The powder is then cooled to room temperature in the furnace to obtain a cobalt-iron-germanium Hasler alloy.

[0011] Preferably, the mass ratio of the grinding balls to the mixed raw material powder is 4 to 10:1.

[0012] Preferably, the grinding balls are made of tungsten carbide, and the diameters of the grinding balls are 10mm and 6mm respectively, with a mass ratio of 2:1 between the two types of grinding balls.

[0013] Preferably, a high-energy planetary ball mill is used to ball mill the mixed raw material powder at a speed of 300-500 rpm for 30-70 hours, with the mill stopping for 5-10 minutes every 30 minutes to cool it down and prevent the gas pressure inside the tank from becoming too high.

[0014] Preferably, the heat treatment temperature is 800–1000℃, the heating rate is 2–10℃ / min, and the heat treatment time is 1–3 days. The purpose of heat treatment is to reduce internal crystal defects caused by the ball milling process and to increase its saturation magnetization and Curie temperature, thereby further improving its high-temperature thermal stability. After heat treatment, a high Curie temperature magnetic cobalt-based Hassler alloy material is obtained, with Curie temperatures all above 1100K and an average particle size ≤20μm.

[0015] Preferably, the weighing process in step (1) is carried out in an inert environment to avoid oxidation of the metal elements by air, and the purity of the cobalt powder, iron powder and germanium powder is 99.99% or higher.

[0016] Preferably, the ratio of the mixed raw material powder to anhydrous ethanol added in step (1) is 8-10g:5-20mL.

[0017] Preferably, in step (2), the ball-milled powder is dried in a drying oven at 60-100°C and passed through a 60-100 mesh sieve.

[0018] The beneficial effects of this invention are:

[0019] Compared with existing technologies, this invention uses ball milling to prepare Hassler alloy powder with high saturation magnetization. Ball milling, also known as mechanical alloying, can effectively alter the surface morphology of the alloy powder, forming flake-like powders with a larger specific surface area. This allows for the control of the electromagnetic parameters of the magnetic alloy, thereby improving its electromagnetic absorption performance. Furthermore, the selection and proportion variation of the Hassler alloy components can effectively increase the saturation magnetization of the magnetic alloy, increase its Curie temperature, and improve its electromagnetic wave absorption performance at high temperatures. This solves the problem that traditional magnetic absorbing materials become paramagnetic above the Curie temperature, resulting in a decline in electromagnetic absorption performance. Simultaneously, the method described in this invention is simple to operate and easy to mass-produce. Traditional hydrothermal methods cannot synthesize the cobalt-iron-germanium Hassler alloy with the compositional proportions of this invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 XRD patterns of the magnetic cobalt-based Hassler alloy materials prepared in Examples 1-3;

[0022] Figure 2 The hysteresis loops of the magnetic cobalt-based Hassler alloy materials prepared in Examples 1-3;

[0023] Figure 3 SEM image of the magnetic cobalt-based Hassler alloy material prepared in Example 1;

[0024] Figure 4 SEM image of the magnetic cobalt-based Hassler alloy material prepared in Example 2;

[0025] Figure 5 SEM image of the magnetic cobalt-based Hassler alloy material prepared in Example 3;

[0026] Figure 6 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 1.

[0027] Figure 7 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 2.

[0028] Figure 8 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 3. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] 1. Weigh 4.38g of cobalt powder, 2.59g of iron powder, and 2.02g of germanium powder (all with a purity of 99.99%) in an inert environment. Mix them thoroughly and place them in a tungsten carbide grinding jar. Add 20ml of anhydrous ethanol as a process control agent. Weigh 30g of tungsten carbide grinding balls with a diameter of 10mm and 60g of tungsten carbide grinding balls with a diameter of 6mm, and add them to the grinding jar.

[0032] 2. The mixture was ball-milled for 70 hours using a planetary ball mill at 450 rpm with a 6-minute pause every 30 minutes. The ball-milled powder was then removed and dried in a drying oven at 60°C. The dried powder was then passed through a 100-mesh sieve to obtain flake-like magnetic alloy powder with an average particle size of 20 μm.

[0033] 3. Load the magnetic alloy powder into an alumina crucible and seal it into a vacuum quartz tube.

[0034] 4. Annealing was performed using a muffle furnace, with the temperature increased to 900℃ at a rate of 2℃ / min and held for 3 days. The mixture was then cooled to room temperature in the furnace to obtain the magnetic cobalt-based Hassler alloy material Co2Fe. 1.25 Ge 0.75 Its Curie temperature is 1108K.

[0035] Example 2

[0036] Example 2 differs from Example 1 in that: in step 1, 4.45g of cobalt powder, 3.16g of iron powder, and 1.37g of germanium powder are added; otherwise, it is the same as in Example 1. A magnetic cobalt-based Hassler alloy material, Co2Fe, is obtained. 15 Ge 0.5 Its Curie temperature is 1130K.

[0037] Example 3

[0038] Example 3 differs from Example 1 in that: in step 1, 4.53g of cobalt powder, 3.76g of iron powder, and 0.69g of germanium powder were added; otherwise, it was the same as in Example 1. A magnetic cobalt-based Hassler alloy material, Co2Fe, was obtained. 1.75 Ge 0.25 Its Curie temperature is 1156K.

[0039] Figure 1 The magnetic cobalt-based Hassler alloy materials prepared in Examples 1-3 showed no discrepancies in their diffraction peaks compared with the standard PDF card, indicating that the samples were successfully synthesized.

[0040] Figure 2 The hysteresis loops of the magnetic cobalt-based Hassler alloy materials prepared in Examples 1-3 exhibit excellent soft magnetic properties and have extremely high saturation magnetization.

[0041] Figure 3-5 The images show SEM images of the magnetic cobalt-based Hassler alloy materials prepared in Examples 1-3. As can be seen from the images, the alloy powder is in the form of small, flake-like particles.

[0042] Performance testing experiment

[0043] 1. This invention uses a vector network analyzer as a testing device to measure the electromagnetic parameters of the magnetic cobalt-based Hassler alloy materials prepared in Examples 1 to 3 by means of the coaxial transmission line method.

[0044] 2. First, use calibration kits to calibrate the test system. The main purpose of this is to reduce system errors caused by the environment and the test system.

[0045] 3. To measure the electromagnetic parameters of the powder sample, the magnetic cobalt-based Hassler alloy material and the binder paraffin are first mixed and then pressed into a coaxial ring using a custom coaxial mold.

[0046] 4. In step 3, the mass of the coaxial ring is 0.1g. Among them, the mass ratio of paraffin wax is 70% (0.07g), and the mass ratio of alloy powder mixture is 30% (0.03g).

[0047] The test conditions for samples in Examples 1-3 were all the same, with thicknesses ranging from 1 to 3 mm. First, the electromagnetic parameters of the samples, namely the complex permittivity and complex permeability, were obtained through testing. Then, the absorption performance at thicknesses of 2-2.5 mm was calculated using the following formula:

[0048]

[0049]

[0050] Where j is the imaginary unit, f is the frequency, d is the thickness of the sample, and c is the speed of light.

[0051] Test results are as follows Figure 6-8 As shown.

[0052] Figure 6 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 1. The material has excellent electromagnetic wave absorption performance of -37.81dB at 12.04GHz.

[0053] Figure 7 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 2. The material has excellent electromagnetic wave absorption performance of -39.14dB at 8.56GHz.

[0054] Figure 8 This is a schematic diagram of the reflection loss of the magnetic cobalt-based Hassler alloy material prepared in Example 3. The material has excellent electromagnetic wave absorption performance of -39.3dB at 15.56GHz.

[0055] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a cobalt-based Hassler alloy material, characterized in that, Includes the following steps: (1) Weigh cobalt powder, iron powder and germanium powder in a molar ratio of 2:(1~1.75):(0.25~1), mix them into a mixed raw material powder, place it in a tungsten carbide grinding jar, add anhydrous ethanol as a process control agent, add grinding balls, and ball mill. (2) Dry and sieve the ball milled powder obtained in step 1, take the magnetic alloy powder under the sieve and seal it into a vacuum quartz tube, heat treat it with a muffle furnace, and cool it to room temperature with the furnace to obtain cobalt-iron-germanium Hasler alloy. The mass ratio of the grinding balls to the mixed raw material powder is 4~10:1; The grinding balls are made of tungsten carbide, and the diameters of the grinding balls are 10mm and 6mm respectively, with a mass ratio of 2:1 between the two types of grinding balls; The mixed raw material powder was ball-milled using a high-energy planetary ball mill at a speed of 300-500 rpm for 30-70 hours, with a 5-10 minute pause every 30 minutes during the process. The heat treatment temperature is 800~1000℃, the heat treatment heating rate is 2-10℃ / min, and the heat treatment time is 1~3 days.

2. The method for preparing a cobalt-based Hassler alloy material according to claim 1, characterized in that, The weighing process in step (1) is carried out in an inert environment, and the purity of the cobalt powder, iron powder and germanium powder is above 99.99%.

3. The method for preparing a cobalt-based Hassler alloy material according to claim 1, characterized in that, In step (1), the ratio of the mixed raw material powder to anhydrous ethanol is 8-10g:5-20mL.

4. The method for preparing a cobalt-based Hassler alloy material according to claim 1, characterized in that, In step (2), the ball-milled powder is dried in a drying oven at 60-100℃ and passed through a 60-100 mesh sieve.

5. The cobalt-based Hassler alloy material prepared by the preparation method according to any one of claims 1-4.

6. The application of the cobalt-based Hassler alloy material according to claim 5 in electromagnetic absorption.

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