A hafnium oxide iron-based soft magnetic material, its preparation method, and an inductive component

Abstract

This application is applicable to the field of materials technology, and provides a hafnium oxide iron-based soft magnetic material, a preparation method thereof, and an inductive component; the hafnium oxide iron-based soft magnetic material is obtained by coating a layer of hafnium oxide on the surface of carbonyl iron powder. This application effectively improves the high-temperature resistance and corrosion resistance of carbonyl iron powder, and provides basic material support for electronic components such as inductors working under high-temperature conditions; in addition, the preparation process of this application is simple, the reaction conditions are easy to control, and it can be applied to industrialized large-scale production.

Description

Technical Field

[0001] This application belongs to the technical field of materials, and particularly relates to a hafnium iron-based soft magnetic material, a preparation method thereof, and an inductive component. Background Art

[0002] With the development of communication technology and the digitalization of electronic products, higher requirements are put forward for soft magnetic materials and components. Under high-temperature working conditions, as the temperature approaches the Curie temperature, the magnetic properties of traditional soft magnetic materials will decrease sharply. At the same time, they are extremely easy to oxidize in the air, and after returning to room temperature, it may cause permanent loss of the magnetic properties of the materials, which greatly limits the application of soft magnetic materials under high-temperature working conditions.

[0003] It can be seen that the existing soft magnetic materials have poor high-temperature resistance and corrosion resistance and cannot be applied to work under high-temperature conditions. Summary of the Invention

[0004] An embodiment of this application provides a hafnium iron-based soft magnetic material, aiming to solve the problems that the existing soft magnetic materials have poor high-temperature resistance and corrosion resistance and cannot be applied to work under high-temperature conditions.

[0005] An embodiment of this application is implemented as follows. A hafnium iron-based soft magnetic material is obtained by coating a layer of hafnium oxide on the surface of carbonyl iron powder.

[0006] An embodiment of this application also provides a preparation method of a hafnium iron-based soft magnetic material, including:

[0007] Dissolve hafnium oxychloride hydrate in deionized water to obtain a clear hafnium-containing solution;

[0008] Adjust the pH of the clear hafnium-containing solution to 8-10 to obtain a hafnium-containing suspension;

[0009] Centrifuge the hafnium-containing suspension to obtain a hydrated hafnium hydroxide precipitate;

[0010] Dissolve the hydrated hafnium hydroxide precipitate in nitric acid and hydrogen peroxide to obtain a coating sol;

[0011] Add carbonyl iron powder to the coating sol for uniform mixing, and after drying treatment, perform high-temperature calcination treatment to obtain the product.

[0012] An embodiment of this application also provides an inductive component, and the inductive component includes the above-mentioned hafnium iron-based soft magnetic material.

[0013] In the embodiment of the present application, the sol-gel method is adopted to uniformly coat hafnium oxide at the nanoscale on carbonyl iron powder, and then through high-temperature calcination, a uniform hafnium oxide shell is formed, effectively improving the high-temperature resistance and corrosion resistance of carbonyl iron powder, providing basic material support for electronic components such as inductors working under high-temperature conditions; in addition, the preparation process of the present application is simple, the reaction conditions are easy to control, and it can be applied to industrialized large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the microscopic morphology diagram of the hafnium oxide iron-based soft magnetic material provided by the embodiment of the present application;

[0015] Figure 2 is the XRD diagram of the hafnium oxide iron-based soft magnetic material provided by the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with specific embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] In the embodiment of the present application, in order to solve the problems that the existing soft magnetic materials have poor high-temperature resistance and corrosion resistance and cannot be applied to work under high-temperature conditions, a new type of soft magnetic material with excellent soft magnetic properties and capable of withstanding high temperatures and corrosion when used as a magnetic core is provided. Through the sol-gel method, nanoscale hafnium oxide is uniformly coated on carbonyl iron powder, and then through high-temperature calcination, a uniform hafnium oxide shell is formed, effectively improving the high-temperature resistance and corrosion resistance of carbonyl iron powder, providing basic material support for electronic components such as inductors working under high-temperature conditions; in addition, the preparation process of the present application is simple, the reaction conditions are easy to control, and it can be applied to industrialized large-scale production.

[0018] Specifically, the embodiment of the present application provides a hafnium oxide iron-based soft magnetic material, which is obtained by coating a layer of hafnium oxide on the surface of carbonyl iron powder.

[0019] The embodiment of the present application also provides a preparation method for the above-mentioned hafnium oxide iron-based soft magnetic material, including the following steps:

[0020] Step S1: Dissolve hafnium oxychloride hydrate in deionized water to obtain a clear hafnium-containing solution.

[0021] In the embodiment of the present application, the hafnium content in the clear hafnium-containing solution is 0.1-0.5 mol / L.

[0022] Step S2: Adjust the pH of the clear hafnium-containing solution to 8-10 to obtain a hafnium-containing suspension.

[0023] In an embodiment of the present application, optionally, step S2 includes:

[0024] Adding ammonia water to the hafnium-containing clarified solution to adjust the pH to 8-10 to obtain a hafnium-containing suspension.

[0025] Wherein, the concentration of the ammonia water is 0.5-2 mol / L.

[0026] Step S3: Centrifuging the hafnium-containing suspension to obtain a hydrated hafnium hydroxide precipitate.

[0027] Step S4: Dissolving the hydrated hafnium hydroxide precipitate in nitric acid and hydrogen peroxide, and adjusting the pH to 0.5-1 to obtain a coating sol.

[0028] In an embodiment of the present application, before step S4, it further includes:

[0029] Washing and centrifuging the hydrated hafnium hydroxide precipitate multiple times, adding a silver nitrate solution to the supernatant obtained by centrifugation, and obtaining a flocculent silver chloride precipitate.

[0030] Specifically, dropping a silver nitrate solution into the supernatant obtained by the last centrifugation. If no white flocculent silver chloride precipitate is formed, it indicates that all the chloride ions have been washed away.

[0031] In an embodiment of the present application, the concentration of the nitric acid is 1-3 mol / L; the mass fraction of the hydrogen peroxide is 30%.

[0032] This is the peptization process. Nitric acid provides an acidic environment, and hydrogen peroxide acts as a promoting solvent to accelerate the dissolution of the precipitate. The chemical equation can be simply expressed as Hf(OH)4 + HNO3 → Hf(OH)3NO3 + H2O. By measuring the pH value of the solution at 0.5-1 to control the dosage of nitric acid and hydrogen peroxide, slight changes in the dosage ratio of nitric acid, hydrogen peroxide, and hydrated hafnium hydroxide precipitate have no significant impact on the result.

[0033] Step S5: Adding carbonyl iron powder to the coating solution for uniform mixing, and performing high-temperature calcination after drying treatment to obtain the product.

[0034] In an embodiment of the present application, the drying treatment conditions are: drying temperature 60-80 °C, drying time 3-6 hours.

[0035] In an embodiment of the present application, the high-temperature calcination treatment conditions are: calcination temperature 500-600 °C, calcination time 1-2 hours, and an inert gas is introduced as a protective gas throughout the calcination process.

[0036] An embodiment of the present application further provides an inductive element, and the inductive element includes the above-mentioned hafnium oxide-based soft magnetic material.

[0037] Examples of certain embodiments of the present application are given below, and the purpose is not to limit the scope of the present application.

[0038] In addition, it should be noted that the values given in the following examples are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0039] Example 1

[0040] 1) Place 4.10 g of HfOCl2·8H2O in 100 mL of deionized water and stir magnetically until fully dissolved to obtain a clear hafnium-containing solution with a concentration of 0.1 mol / L.

[0041] 2) Dilute ammonia water with a mass fraction of 25 - 28% to a NH3·H2O solution with a concentration of 1 mol / L, and slowly add it dropwise to the above-mentioned clear hafnium-containing solution until the solution pH = 8 to obtain a uniform hafnium-containing suspension.

[0042] 3) Centrifuge the above-mentioned hafnium-containing suspension with a centrifuge at a speed of 5000 r / min for 3 minutes to obtain a Hf(OH)4 hydrated precipitate. Then wash the precipitate thoroughly with deionized water and centrifuge again. This process is repeated 6 - 7 times. Drop silver nitrate solution into the supernatant obtained by centrifugation for the last time. If no white AgCl precipitate is formed, it indicates that all the chloride ions have been washed clean.

[0043] 4) Take the above-mentioned washed Hf(OH)4 hydrated precipitate, add 100 mL of HNO3 solution with a concentration of 2 mol / L and 2 mL of hydrogen peroxide with a mass fraction of 30% to form a white turbid solution. Stir this solution magnetically for 24 h to obtain a clear and transparent coating sol.

[0044] 5) Take 1 mL of the above-mentioned coating sol, add 5.6 g of carbonyl iron powder, stir well, and then place it in a vacuum drying oven and dry it under vacuum for 5 hours at a temperature of 60 °C until a dry powder is obtained.

[0045] 6) Calcine the above-mentioned powder in a tube furnace. The calcination temperature of the tube furnace is 500 - 600 °C, and the calcination time is 1 hour. Argon is introduced as a protective gas throughout the calcination process to ensure that Hf(OH)4 is fully converted into HfO2, and a magnetic carbonyl iron powder coated with HfO2, that is, a hafnium oxide iron-based soft magnetic material, is obtained.

[0046] Example 2

[0047] 1) Place 8.19 g of HfOCl₂·8H₂O in 100 ml of deionized water and stir magnetically until it is completely dissolved to obtain a clear hafnium-containing solution with a concentration of 0.2 mol / L;

[0048] 2) Dilute ammonia water with a mass fraction of 25 - 28% into an NH₃·H₂O solution with a concentration of 1 mol / L, and slowly add it dropwise to the above-mentioned clear hafnium-containing solution until the pH of the solution is 8 to obtain a uniform hafnium-containing suspension;

[0049] 3) Centrifuge the above-mentioned hafnium-containing suspension with a centrifuge at a rotation speed of 5000 r / min for 3 minutes to obtain a Hf(OH)₄ hydrated precipitate, then wash the precipitate thoroughly with deionized water, and then perform centrifugal separation again. This process is repeated 6 - 7 times. Add silver nitrate solution dropwise to the supernatant obtained by centrifugation for the last time. If no white AgCl precipitate is formed, it indicates that all the chloride ions have been washed away;

[0050] 4) Take the above-mentioned washed precipitate, add 100 ml of a HNO₃ solution with a concentration of 2 mol / L and 2 ml of hydrogen peroxide with a mass fraction of 30% to form a white turbid solution, and stir this solution magnetically for 24 h to obtain a clear and transparent coated sol;

[0051] 5) Take 1 ml of the above-mentioned coated sol, add 5.6 g of carbonyl iron powder, stir well, and then place it in a vacuum drying oven to dry in vacuum for 5 hours at a temperature of 60 °C until a dry powder is obtained;

[0052] 6) Calcinate the above-mentioned powder in a tube furnace. The calcination temperature of the tube furnace is 500 - 600 °C, and the calcination time is 1 hour. Argon is introduced as a protective gas throughout the calcination process to ensure that Hf(OH)₄ is fully converted into HfO₂ to obtain magnetic carbonyl iron powder coated with HfO₂, that is, hafnium oxide iron-based soft magnetic material.

[0053] Example 3

[0054] A preparation method of a high-temperature corrosion-resistant HfO₂-coated iron-based soft magnetic material is as follows:

[0055] 1) Place 16.38 g of HfOCl₂·8H₂O in 100 ml of deionized water and stir magnetically until it is completely dissolved to obtain a clear hafnium-containing solution with a concentration of 0.4 mol / L;

[0056] 2) Dilute ammonia water with a mass fraction of 25 - 28% into an NH₃·H₂O solution with a concentration of 1 mol / L, and slowly add it dropwise to the above-mentioned clear hafnium-containing solution until the pH of the solution is 8 to obtain a uniform suspension;

[0057] 3) Centrifuge the above suspension at a centrifuge speed of 5000 r / min for 3 minutes to obtain a hydrated Hf(OH)4 precipitate. Then, thoroughly wash the precipitate with deionized water and perform centrifugal separation again. This process is repeated 6 - 7 times. Add silver nitrate solution dropwise to the supernatant obtained from the last centrifugation. If no white AgCl precipitate forms, it indicates that all the chloride ions have been washed away;

[0058] 4) Take the above - washed precipitate, add 100 ml of HNO3 solution with a concentration of 2 mol / L and then add 2 mL of hydrogen peroxide with a mass fraction of 30% to form a white turbid solution. Magnetically stir this solution for 24 h to obtain a clear and transparent sol;

[0059] 5) Take 1 mL of the above sol, add 5.6 g of carbonyl iron powder, stir well, and then place it in a vacuum drying oven to dry under vacuum at 60 °C for 5 hours until a dry powder is obtained;

[0060] 6) Calcinate the above powder in a tubular furnace. The calcination temperature of the tubular furnace is 500 - 600 °C, and the calcination time is 1 hour. Argon is introduced as a protective gas throughout the calcination process to ensure that Hf(OH)4 is fully converted to HfO2, obtaining magnetic carbonyl iron powder coated with HfO2 on the surface, that is, hafnium - oxide - based soft magnetic material.

[0061] Comparative Example 1

[0062] Soft magnetic material without hafnium dioxide coating.

[0063] Perform scanning electron microscope testing on the hafnium - oxide - based soft magnetic material prepared in Example 1. The morphology of the obtained material is as Figure 1 shown.

[0064] Perform XRD testing on the hafnium - oxide - based soft magnetic material prepared in Example 1. The results are as Figure 2 shown.

[0065] First, perform vibrating sample magnetometer testing on the hafnium - oxide - based soft magnetic material prepared in Example 1 and the soft magnetic material without hafnium dioxide coating in Comparative Example 1. Then, sinter them in a tubular furnace at 250 °C for 3 h and perform vibrating sample magnetometer testing again. The test results are shown in Table 1 below.

[0066] Table 1 Main performance indicators of Example 1 and Comparative Example 1 before and after sintering

[0067]

[0068]

[0069] In summary, the embodiment of the present application adopts the sol-gel method to uniformly coat hafnium oxide at the nanoscale on carbonyl iron powder, and then forms a uniform hafnium oxide shell through high-temperature calcination, effectively improving the high-temperature resistance and corrosion resistance of carbonyl iron powder, and providing basic material support for electronic components such as inductors working under high-temperature conditions; in addition, the preparation process of the present application is simple, the reaction conditions are easy to control, and it can be applied to industrialized large-scale production.

[0070] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A hafnium iron-based soft magnetic material, characterized in that, The hafnium oxide iron-based soft magnetic material is obtained by coating a layer of hafnium oxide on the surface of carbonyl iron powder.

2. A preparation method of a hafnium iron-based soft magnetic material, characterized in that, It includes: Dissolve hafnium oxychloride hydrate in deionized water to obtain a clear hafnium-containing solution. Adjust the pH of the clear hafnium-containing solution to 8-10 to obtain a hafnium-containing suspension. Centrifuge the hafnium-containing suspension to obtain hafnium hydroxide hydrate precipitate. Dissolve the hafnium hydroxide hydrate precipitate in nitric acid and hydrogen peroxide to obtain a coating sol. Add carbonyl iron powder to the coating sol for uniform mixing, and after drying treatment, perform high-temperature calcination treatment to obtain the product.

3. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, characterized in that, The hafnium content in the clear hafnium-containing solution is 0.1-0.5 mol / L.

4. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, wherein, The step of adjusting the pH of the clear hafnium-containing solution to 8-10 to obtain a hafnium-containing suspension includes: Add ammonia water to the clear hafnium-containing solution to adjust the pH to 8-10 to obtain a hafnium-containing suspension.

5. The preparation method of the hafnium iron-based soft magnetic material according to claim 4, characterized in that, The concentration of the ammonia water is 0.5-2 mol / L.

6. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, wherein, Before the step of dissolving the hafnium hydroxide hydrate precipitate in nitric acid and hydrogen peroxide to obtain a coating sol, it further includes: Wash and centrifuge the hafnium hydroxide hydrate precipitate multiple times, add silver nitrate solution to the supernatant obtained by centrifugation treatment to obtain flocculent silver chloride precipitate.

7. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, wherein The concentration of the nitric acid is 1-3 mol / L; the mass fraction of the hydrogen peroxide is 30%.

8. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, characterized in that, The drying treatment conditions are: drying temperature 60-80 °C, drying time 3-6 hours.

9. The preparation method of the hafnium iron-based soft magnetic material according to claim 2, characterized in that, The high-temperature calcination treatment conditions are: calcination temperature 500-600 °C, calcination time 1-2 hours, and an inert gas is introduced as a protective gas during the whole calcination process.

10. An inductive component, characterized in that, The inductor element includes the hafnium oxide iron-based soft magnetic material described in claim 1.

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