A nickel-zinc ferrite material and a method for producing the same

Abstract

The application relates to the technical field of ferrite preparation, and particularly provides a nickel-zinc ferrite material and a preparation method thereof; the nickel-zinc ferrite material comprises main components and auxiliary components; the main components contain the following components, and the weight percentage of each component is as follows: Fe2O3 is 68.34-68.76 wt%, NiO is 19.12-19.54 wt%, and the rest is ZnO; the auxiliary components contain 0.1 wt%-0.2 wt% of Co2O3 according to the total weight of the main components; by controlling the content of Fe2O3, NiO, ZnO and Co2O3 in the formula within the above range, the nickel-zinc ferrite material can significantly improve the anti-magnetization performance and the anti-battery interference ability on the basis of maintaining high saturation magnetic induction strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ferrite preparation, in particular to a nickel-zinc ferrite material and a preparation method thereof. BACKGROUND

[0002] With the development of electronic power technology, it is an inevitable trend that electronic devices are developing towards miniaturization, high frequency and large current. Therefore, the performance requirements of soft magnetic materials in electronic devices are increasing. Nickel-zinc ferrite (NiZn ferrite) has excellent high-frequency characteristics, good temperature stability, various formulations, large nonlinearity, simple process and other advantages, and is widely used in the fields of television, communication, instruments and meters, automatic control, electronic countermeasure, etc.

[0003] At present, NiZn ferrite materials can be divided into three categories according to their uses and characteristics: high frequency, high saturation magnetic induction and high initial permeability. There are inevitable shortcomings, for example, the material with high saturation magnetic induction and low permeability has good superposition performance, but due to its low magnetization resistance, it can only be used in low-amplitude alternating magnetic field, and if used in electronic devices, external magnetic field interference may cause a significant reduction in device performance. The nickel-zinc ferrite produced by existing manufacturers is difficult to obtain the dual characteristics of high saturation magnetic induction and magnetization resistance.

[0004] For example, CN104030669A discloses a filter-pressing forming preparation method of NiZn ferrite. The main components are Fe2O3: 48-54 mol%, ZnO: 30-32 mol%, NiO: 3.5-10 mol%, and CuO: 8-15 mol% in terms of mole percentage; the dopant is V2O5: 0-3 wt% in terms of mass percentage. The saturation magnetic induction of the NiZn ferrite is low. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the defects of the prior art that the nickel-zinc ferrite material cannot simultaneously have high saturation magnetic induction and good magnetization resistance, thereby providing a nickel-zinc ferrite material and a preparation method thereof.

[0006] To this end, in a first aspect, the present application provides a nickel-zinc ferrite material, which comprises main components and auxiliary components. In terms of the total weight of the main components, the main components contain the following components, and the weight percentage of each component is: Fe2O3 is 68.34-68.76 wt%, NiO is 19.12-19.54 wt%, and the balance is ZnO; in terms of the total weight of the main components, the auxiliary components include 0.1 wt%-0.2 wt% of Co2O3.

[0007] In a second aspect, the present application provides a preparation method of the nickel-zinc ferrite material, comprising mixing Fe2O3, NiO and ZnO according to a weight ratio, first grinding the mixture, pre-sintering to obtain pre-sintered material, mixing the pre-sintered material with auxiliary components, second grinding, granulating, molding and sintering the mixture to obtain the nickel-zinc ferrite material.

[0008] Further, the first grinding and / or the second grinding is ball milling.

[0009] Further, the ball milling is performed for 2-3 hours; and / or the ball milling is performed at a rotation speed of 350-450 rpm and a material-to-ball ratio of 2-3:1.

[0010] The material-to-ball ratio is a mass ratio of the material to be ground to the ball milling medium.

[0011] Water is further added before the ball milling, and a material-to-water ratio is 3:4-5. The material-to-water ratio is a mass ratio of the material to be ground to water.

[0012] Further, the pre-sintering is performed at a temperature of 900-950 ℃ for 2-3 hours.

[0013] Further, the pre-sintering further comprises a first temperature rising stage of rising from room temperature to 280-320 ℃ at a temperature rising rate of 80-100 ℃ / h and a second temperature rising stage of rising from 280-320 ℃ to 900-950 ℃ at a temperature rising rate of 120-140 ℃ / h before reaching the pre-sintering temperature.

[0014] Further, the granulating comprises the steps of mixing a binder and screening and crushing.

[0015] Preferably, the binder comprises a PVA adhesive.

[0016] Preferably, the binder accounts for 8-12 wt% of the total mass of the pre-sintered material.

[0017] Further, the sintering is performed at a temperature of 1100-1200 ℃ for 2-3 hours; and preferably, the sintering further comprises rising from room temperature to 190-210 ℃ at a temperature rising rate of 85-95 ℃ / h, rising from 190-210 ℃ to 440-460 ℃ at a temperature rising rate of 60-65 ℃ / h, and rising from 440-460 ℃ to 1100-1200 ℃ at a temperature rising rate of 140-160 ℃ / h before reaching the sintering temperature.

[0018] Further, the preparation method further comprises a step of screening after drying after the first grinding or the second grinding.

[0019] Further, the preparation method comprises the following steps:

[0020] (1) main component mixing and first grinding: Fe2O3, NiO, ZnO are mixed according to the weight ratio, and the mixture is ball milled and dried; the ball milling time is 2-3h, the rotating speed is 350-450rpm, and the ratio of material to ball is 2-3:1;

[0021] (2) pre-sintering: the dried material in step (1) is sieved, then heated from room temperature to 280-320℃ at a heating rate of 80-100℃ / h, heated from 280-320℃ to 900-950℃ at a heating rate of 120-140℃ / h, and then kept at 900-950℃ for 2-3h to obtain a pre-sintered material;

[0022] (3) doping and second grinding: the pre-sintered material is sieved and mixed with auxiliary components, and the mixture is ball milled and dried; the ball milling time is 2-3h, and the rotating speed is 350-450rpm;

[0023] (4) granulation: the dried material in step (3) is sieved, mixed with a binder, and then sieved and crushed;

[0024] (5) forming: the crushed material in step (4) is pressed into a shape;

[0025] (6) sintering: the formed material in step (5) is sintered in an air atmosphere, and the sintering process is as follows: heated from room temperature to 190-210℃ at a heating rate of 85-95℃ / h, heated from 190-210℃ to 440-460℃ at a heating rate of 60-65℃ / h, heated from 440-460℃ to 1100-1200℃ at a heating rate of 140-160℃ / h, and then sintered at 1100-1200℃ for 2-3h to obtain a nickel-zinc ferrite material.

[0026] The technical scheme of the present application has the following advantages:

[0027] 1. The nickel-zinc ferrite material provided by the present application comprises main components and auxiliary components, and the main components contain the following components, each component having a weight percentage of: Fe2O3 68.34-68.76wt%, NiO 19.12-19.54wt%, and the balance being ZnO; the auxiliary components include 0.1wt%-0.2wt% Co2O3 based on the total weight of the main components; by controlling the content of Fe2O3, NiO, ZnO and Co2O3 in the formula within the above range, the nickel-zinc ferrite material significantly improves the anti-magnetization performance (anti-electromagnetic interference ability) while maintaining high saturation magnetic induction. The prepared material has good anti-magnetization performance, the change rate of permeability before and after magnetization is less than 4%, which can prevent the performance from being greatly reduced due to external magnetic field interference. And Bs is greater than 460mT.

[0028] 2.The preparation method of the nickel-zinc ferrite material provided by the application, comprising the following steps: mixing Fe2O3, NiO and ZnO in a certain proportion, grinding the mixture for the first time, obtaining pre-sintered material through pre-sintering, mixing the pre-sintered material with auxiliary components, and grinding the mixture for the second time, granulating, shaping and sintering to obtain the nickel-zinc ferrite material, wherein the nickel-zinc ferrite material is prepared by using a traditional grinding method (for example, a mechanical ball milling method), and the manufacturing process is simple and convenient for production.

[0029] 3.The preparation method of the nickel-zinc ferrite material provided by the application, wherein in the pre-sintering process, the pre-sintering temperature is controlled to be 900-950℃, the time is controlled to be 2-3h, and before reaching the pre-sintering temperature, a first temperature rising stage of rising from room temperature to 280-320℃ at a temperature rising rate of 80-100℃ / h and a second temperature rising stage of rising from 280-320℃ to 900-950℃ at a temperature rising rate of 120-140℃ / h are further included, so as to improve the experimental efficiency.

[0030] In the sintering process, the sintering temperature is controlled to be 1100-1200℃, the time is controlled to be 2-3h, and before reaching the sintering temperature, a process of rising from room temperature to 190-210℃ at a temperature rising rate of 85-95℃ / h, rising from 190-210℃ to 440-460℃ at a temperature rising rate of 60-65℃ / h and rising from 440-460℃ to 1100-1200℃ at a temperature rising rate of 140-160℃ / h are further included, so as to further improve the shrinkage rate of the sample ring, improve the density, and be beneficial to improving Bs and permeability. DETAILED DESCRIPTION

[0031] The following examples are provided to better further understand the application, and are not limited to the best mode, and do not constitute a limitation on the content and protection scope of the application, and any person under the inspiration of the application or the combination of the application with other prior art features can obtain any product same or similar to the application, which falls within the protection scope of the application.

[0032] In the examples, the specific experimental steps or conditions are not specified, and can be operated according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not specified by the manufacturer, and are conventional reagent products that can be obtained by purchase.

[0033] Example 1

[0034] The embodiment provides a nickel-zinc ferrite material and a preparation method thereof, comprising the following steps:

[0035] (1) Main component mixing and first grinding: Fe2O3, NiO and ZnO are weighed according to the weight ratio of Fe2O3: 68.55wt%, NiO: 19.33wt%, and the rest is ZnO, mixed as the main component. 300g of the prepared main component is added to a ball mill tank, 100g of zirconia balls is added as the ball mill medium, 450g of deionized water is added, and the slurry is dried after being ball milled by a planetary ball mill at a speed of 391r / min for two and a half hours.

[0036] (2) Pre-sintering: The dried slurry is sieved through a 30-mesh sieve and then pre-sintered to cause a solidification reaction to obtain a pre-sintered material. The pre-sintering process is as follows: the temperature is raised from room temperature to 300℃ at a rate of 90℃ / h, the temperature is raised from 300℃ to 950℃ at a rate of 130℃ / h, the temperature is kept at 950℃ for 2h, and the furnace is naturally cooled.

[0037] (3) Doping and second grinding: After the pre-sintered material is cooled to room temperature, it is sieved through a 30-mesh sieve and then doped with 0.1wt% of Co2O3 based on the mass of the main component, and then added to a ball mill tank, 100g of zirconia balls is added as the ball mill medium, 450g of deionized water is added, and the slurry is dried after being ball milled by a planetary ball mill at a speed of 391r / min for two and a half hours.

[0038] (4) Granulation: The dried slurry is sieved through a 30-mesh sieve to obtain a powder, and 10wt% of PVA glue (solid content is 36%) is added to the powder and stirred to form granules, and then the granules are broken by a 30-mesh sieve.

[0039] (5) Molding: A mold with an outer diameter of 20mm and an inner diameter of 10mm is used to press a sample ring at a pressure of 6MPa.

[0040] (6) Sintering: The sample ring is placed in a muffle furnace and sintered in an air atmosphere, and the sintering process is as follows: the temperature is raised from room temperature to 200℃ at a rate of 90℃ / h, the temperature is raised from 200℃ to 450℃ at a rate of 62.5℃ / h, and the temperature is raised from 450℃ to 1200℃ at a rate of 150℃ / h; finally, sintering is carried out at 1200℃ for 2h.

[0041] Example 2

[0042] This example provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of Example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.2% of the mass of the main component.

[0043] Example 3

[0044] This example provides a nickel-zinc ferrite material and a preparation method thereof, which comprises the following steps:

[0045] (1) Main component mixing and first grinding: Fe2O3, NiO and ZnO are weighed according to the weight ratio of Fe2O3: 68.76wt%, NiO: 19.12wt%, and the rest is ZnO, mixed as the main component. 300g of the prepared main component is added to a ball mill tank, 150g of zirconia balls are added as the ball mill medium, 450g of deionized water is added, and the slurry is dried after being ball milled by a planetary ball mill at a speed of 350rpm for 2h.

[0046] (2) Calcination: the dried slurry is sieved with a 30-mesh sieve and then calcined to make it undergo a solidification reaction to obtain a calcined material. The calcination process is as follows: the temperature is raised from room temperature to 280℃ at a rate of 100℃ / h, the temperature is raised from 280℃ to 900℃ at a rate of 140℃ / h, the temperature is kept at 900℃ for 3h, and the furnace is naturally cooled.

[0047] (3) Doping and second grinding: after the calcined material is cooled to room temperature, it is sieved with a 30-mesh sieve and then doped with 0.1wt% of Co2O3 based on the mass of the main component, and then put into a ball mill tank, 100g of zirconia balls are added as the ball mill medium, 450g of deionized water is added, and the slurry is dried after being ball milled by a planetary ball mill at a speed of 391rpm for two and a half hours.

[0048] (4) Granulation: the dried slurry is sieved with a 50-mesh sieve to obtain a powder, 8wt% of PVA glue (solid content is 36%) is added to the powder, and the mixture is stirred and granulated, and then broken with a 30-mesh sieve.

[0049] (5) Molding: a mold with an outer diameter of 20mm and an inner diameter of 10mm is used to press a sample ring at a pressure of 6MPa.

[0050] (6) Sintering: the sample ring is placed in a muffle furnace and sintered in an air atmosphere, and the sintering process is as follows: the temperature is raised from room temperature to 210℃ at a rate of 95℃ / h, the temperature is raised from 210℃ to 460℃ at a rate of 60℃ / h, and the temperature is raised from 460℃ to 1100℃ at a rate of 150℃ / h; finally, sintering is carried out at 1100℃ for 3h.

[0051] Example 4

[0052] This example provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of Example 1, except that the weight ratio of the components in the main component is different. In this example, the weight ratio of the components in the main component is as follows: Fe2O3: 68.34wt%, NiO: 19.54wt%, and the rest is ZnO.

[0053] Comparative Example 1

[0054] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0055] Comparative example 2

[0056] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0057] Comparative example 3

[0058] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0059] Comparative example 4

[0060] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0061] Comparative example 5

[0062] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0063] Comparative example 6

[0064] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0065] Comparative example 7

[0066] The comparative example 1 provides a nickel-zinc ferrite material and a preparation method thereof, which are basically the same as those of the example 1, except that the amount of Co2O3 added in step (3) is adjusted to 0.3% of the mass of the main components.

[0067] Core magnetic property test:

[0068] (1) Magnetic permeability test: The magnetic rings of each example and the comparative example were tested for the real part of the magnetic permeability μ1 (i.e., initial magnetic permeability μ') at 1 MHz using an Agilent E4991A analyzer. The results are shown in Table 1.

[0069] (2) Anti-magnetization performance test: The magnetic rings of each example and the comparative example were magnetized once clockwise around the center along the axis of the sample ring using a magnet with a surface magnetic induction of 320 mT, and then the real part of the magnetic permeability μ2 of the magnetized sample ring was tested at 1 MHz using an Agilent E4991A analyzer, and the change rate of the magnetic permeability before and after magnetization was calculated using the formula (μ1-μ2) / μ1. The results are shown in Table 1.

[0070] (3) Bs test: The magnetic rings of each example and the comparative example were uniformly wound with 25 turns of a copper wire with a diameter of 0.4 mm. The test conditions were 50 Hz, 1 V, 25°C, and a maximum applied magnetic field of 4000 A / m, and the results are shown in Table 2.

[0071] Table 1 Anti-magnetization performance test results

[0072] Initial magnetic permeability μ' Change rate of magnetic permeability before and after Example 1 104.3 0.48％ Example 2 99.8 3.76％ Example 3 105.6 0.44％ Example 4 103.9 0.43％ Comparative Example 1 92.8 8.56％ Comparative Example 2 74.6 13.56％ Comparative Example 3 126.8 9.65％ Comparative Example 4 93.6 6.77％ Comparative Example 5 90.8 8.69％ Comparative Example 6 134.6 8.77％ Comparative Example 7 50.8 1.33％

[0073] Table 2 Saturation magnetic induction test results

[0074]

[0075]

[0076] From the above table, it can be seen that the magnetic permeability of Examples 1-4 is suitable (between 90 and 110), and the anti-magnetization performance is excellent (the change rate of the magnetic permeability before and after magnetization is less than 4%), and Bs > 460 mT. The smaller the absolute value of the magnetic crystalline anisotropy constant K1 of the material, the more difficult it is to produce irreversible magnetization in the material. The K1 of the NiZn ferrite is negative, while the K1 of the Fe 2+ and Co 2+ is a larger positive value, which can correct the K1 of the NiZn ferrite to make its absolute value close to 0. Therefore, the absolute value of the K1 of Examples 1-4 is likely to be small, which makes it have excellent anti-magnetization performance.

[0077] From the comparison of Example 1 and Comparative Examples 1-3, it can be seen that adding too much or too little Co2O3 will cause the absolute value of K1 to increase, the change rate of the magnetic permeability before and after magnetization to increase, and the sub-Co ions to have a freezing magnetic domain effect, and adding too much will also cause the magnetic permeability to decrease. In summary, the amount of Co2O3 also needs to be controlled to be around 0.1 wt% to 0.2 wt%.

[0078] It can be seen from the comparison between Example 1 and Comparative Examples 4-7 that the amounts of Fe2O3, NiO and ZnO need to be strictly controlled within the range required by the present application. If not strictly controlled (too high or too low), the change rate of permeability before and after magnetization will be high. In Comparative Example 6, the content of NiO is too low, which results in a significant decrease of Bs of the nickel-zinc ferrite material. In Comparative Example 7, the content of NiO is too high, which results in a significant decrease of permeability of the nickel-zinc ferrite material.

[0079] Obviously, the above examples are merely illustrative and not intended to limit the embodiments. Based on the above description, those skilled in the art can make other different forms of changes or variations. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A nickel-zinc ferrite material, characterized in that, The nickel-zinc ferrite material comprises a main component and auxiliary components. The main component, with a total weight of 100 wt%, contains the following components, each with the following weight percentage: Fe2O3 68.34~68.76 wt%, NiO 19.12~19.54 wt%, and the balance being ZnO. The auxiliary components, based on the total weight of the main component, include 0.1 wt%~0.2 wt% Co2O3.

2. A method for preparing the nickel-zinc ferrite material according to claim 1, characterized in that, The process involves mixing Fe2O3, NiO, and ZnO in a weight ratio, grinding the mixture for the first time, pre-firing it to obtain a pre-fired material, mixing the pre-fired material with auxiliary components, grinding the mixture for the second time, granulating, molding, and sintering to obtain a nickel-zinc ferrite material.

3. The method for preparing the nickel-zinc ferrite material according to claim 2, characterized in that, The first grinding and / or the second grinding are ball milling.

4. The method for preparing the nickel-zinc ferrite material according to claim 3, characterized in that, The ball milling time is 2-3 hours, the ball milling speed is 350-450 rpm, and the ball-to-material ratio is 2-3:

1.

5. The method for preparing the nickel-zinc ferrite material according to claim 2, characterized in that, The preheating temperature is 900-950℃, and the time is 2-3 hours.

6. The method for preparing the nickel-zinc ferrite material according to claim 5, characterized in that, The pre-firing process includes a first heating stage before reaching the pre-firing temperature, where the temperature is increased from room temperature to 280-320℃ at a heating rate of 80-100℃ / h, and a second heating stage where the temperature is increased from 280-320℃ to 900-950℃ at a heating rate of 120-140℃ / h.

7. The method for preparing the nickel-zinc ferrite material according to claim 2, characterized in that, The granulation process includes steps of mixing in a binder and screening and crushing.

8. The method for preparing the nickel-zinc ferrite material according to claim 7, characterized in that, The adhesive includes PVA adhesive.

9. The method for preparing the nickel-zinc ferrite material according to claim 7, characterized in that, The binder accounts for 8-12 wt% of the total mass of the pre-fired material.

10. The method for preparing the nickel-zinc ferrite material according to claim 2, characterized in that, The sintering temperature is 1100-1200℃, and the time is 2-3 hours.

11. The method for preparing the nickel-zinc ferrite material according to claim 10, characterized in that, Before reaching the sintering temperature, the process includes raising the temperature from room temperature to 190-210℃ at a rate of 85-95℃ / h, raising the temperature from 190-210℃ to 440-460℃ at a rate of 60-65℃ / h, and raising the temperature from 440-460℃ to 1100-1200℃ at a rate of 140-160℃ / h.

12. The method for preparing the nickel-zinc ferrite material according to any one of claims 2-11, characterized in that, The process includes drying and sieving after the first or second grinding.

13. The method for preparing the nickel-zinc ferrite material according to claim 2, characterized in that, The preparation method includes the following steps: (1) Mixing of main components and first grinding: Fe2O3, NiO and ZnO are mixed in weight ratio, and the mixture is ball-milled and dried; the ball milling time is 2-3h, the rotation speed is 350-450rpm, and the material-to-ball ratio is 2-3:1; (2) Pre-calcination: After the material dried in step (1) is sieved, the temperature is increased from room temperature to 280-320℃ at a heating rate of 80-100℃ / h, and then increased from 280-320℃ to 900-950℃ at a heating rate of 120-140℃ / h. The material is then kept at 900-950℃ for 2-3 hours to obtain pre-calcined material. (3) Doping and second grinding: After the pre-calcined material is sieved, it is mixed with auxiliary components, and the mixture is ball-milled and dried; the ball milling time is 2-3 hours and the rotation speed is 350-450 rpm; (4) Granulation: After the material dried in step (3) is sieved, it is mixed with binder and then sieved and crushed; (5) Molding: Press the material crushed in step (4) into shape; (6) Sintering: The material formed in step (5) is sintered in an air atmosphere. The sintering process is as follows: the temperature is raised from room temperature to 190-210℃ at a heating rate of 85-95℃ / h, then raised from 190-210℃ to 440-460℃ at a heating rate of 60-65℃ / h, then raised from 440-460℃ to 1100-1200℃ at a heating rate of 140-160℃ / h, and then sintered at 1100-1200℃ for 2-3 hours to obtain nickel-zinc ferrite material.

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