Mn-Zn soft magnetic ferrite core and sintering method and application thereof
By adjusting the ratio of Fe2+ to Fe3+ and processing at a specific temperature, the high loss problem of manganese-zinc soft magnetic ferrite cores under wide temperature and frequency ranges was solved, and the preparation of low-loss manganese-zinc soft magnetic ferrite cores was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RUYUAN DONGYANGGUANG MAGNETIC MATERIAL
- Filing Date
- 2023-12-29
- Publication Date
- 2026-07-03
AI Technical Summary
The existing sintering process of manganese-zinc soft magnetic ferrite cores results in high losses under conditions of -20 to 140℃ and 100 to 400KHz, making it difficult to meet product performance requirements.
By employing heat preservation treatment under specific temperature and atmosphere conditions, combined with the control of heating, heat preservation, and cooling stages, the ratio of Fe2+ to Fe3+ is regulated to promote complete solid-phase reaction, improve grain growth uniformity, and reduce losses.
Under wide temperature and frequency conditions, the loss of manganese-zinc soft magnetic ferrite cores is significantly reduced, the sintering density is increased, smaller grains are formed, porosity and heterogeneous phases are reduced, and the low loss requirement is met.
Smart Images
Figure CN117819957B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electronic materials technology, and more specifically, to a manganese-zinc soft magnetic ferrite core, its sintering method, and its application. Background Technology
[0002] When processing large ferrite cores using existing sintering processes, the thickness of the cores prevents them from reacting sufficiently during sintering. This results in poor microstructure and electromagnetic properties within the core, leading to significant power quality loss in the manufactured cores and making it difficult to meet product performance requirements.
[0003] To address the issue of insufficient sintering inside bulk magnetic cores, existing technologies disclose a reheating method for manganese-zinc power ferrite cores. While this method can address the problem of insufficient sintering to some extent by controlling specific reheating temperatures, sintering oxygen content, and holding times, it merely reheats the bulk magnetic cores sintered using traditional sintering processes. This method cannot overcome the high loss problem of large-size magnetic cores under conditions of -20 to 140°C and 100 to 400 kHz caused by traditional sintering processes. Summary of the Invention
[0004] The technical problem to be solved by this invention is to overcome the defects and shortcomings of the existing sintering process of manganese-zinc soft magnetic ferrite cores, which results in high losses of the sintered cores under conditions of -20 to 140°C and 100 to 400 kHz. This invention provides a sintering method for manganese-zinc soft magnetic ferrite cores, which involves heat treatment of the blank at the temperature corresponding to the endothermic peak of the manganese-zinc soft magnetic ferrite core material, and improving the densification reaction temperature and sintering temperature. At the same time, it combines heat treatment under specific temperature conditions during the cooling process, which effectively reduces the loss of manganese-zinc soft magnetic ferrite cores under conditions of -20 to 140°C and 100 to 400 kHz, and achieves low loss under wide temperature and wide frequency conditions.
[0005] Another object of the present invention is to provide a manganese-zinc soft magnetic ferrite core prepared by the above-described sintering method.
[0006] Another object of the present invention is to provide the application of the above-mentioned manganese-zinc soft magnetic ferrite core in automotive electronic systems.
[0007] The above-mentioned objective of this invention is achieved through the following technical solution:
[0008] This invention protects a sintering method for a manganese-zinc soft magnetic ferrite core, comprising powder preparation, pressing, and sintering, wherein the sintering includes the following steps:
[0009] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the manganese-zinc soft magnetic ferrite core is kept at its endothermic peak characteristic temperature for 55-65 minutes, then heated to 1100℃ to begin densification, then heated to 1200℃, and then heated to 1245-1255℃.
[0010] S2. Heat preservation stage: Sintering and shaping at 1245~1255℃;
[0011] S3. Cooling stage: When the temperature drops to 1195~1205℃, keep it at that temperature for 30~120min, and continue to cool it to 1155~1165℃, then keep it at that temperature for 60~120min.
[0012] This invention provides a sintering method for large-size manganese-zinc soft magnetic ferrite cores. First, the temperature corresponding to the endothermic peak of the manganese-zinc soft magnetic ferrite core material (i.e., the endothermic peak characteristic temperature) is determined. Then, during subsequent heating, the material is held at this temperature to regulate the Fe content in the soft magnetic ferrite. 2+ with Fe 3+ The proportion (reducing Fe) 2+ (relative content), thereby shifting the loss valley (lowest point) of the manganese-zinc soft magnetic ferrite core to the high-temperature region to reduce high-temperature loss.
[0013] Moreover, compared to traditional low-temperature densification and high-temperature sintering, this invention uses a higher temperature (1100-1200℃) for densification and a lower temperature (1245-1255℃) for sintering, and appropriately extends the sintering time to promote complete solid-phase reaction, improve grain growth uniformity, and form relatively small grains; at the same time, it reduces porosity and heterogeneous phases, thereby reducing the loss of manganese-zinc soft magnetic ferrite cores under conditions of -20-140℃ and 100-400KHz.
[0014] Furthermore, compared to the cooling stage of traditional sintering processes, this invention reduces the temperature difference between the inside and outside of the magnetic core by performing heat preservation treatments at 1195–1205℃ and 1155–1165℃ respectively. This effectively releases the internal stress of the magnetic core and thus effectively improves the core's loss. It should also be noted that the manganese-zinc soft magnetic ferrite core used in the above sintering method is not limited in any way. For example, it can be a manganese-zinc power ferrite core prepared by engraving and / or die rolling; specifically, it can be an EDB18-3 and EC32 core made from HE6 ferrite material blocks, a standard H25*15*10 ring sample engraved from HE6 material, a PQ5050 product corresponding to the HE7A standard ring H25*15*10, and a PQ110 core made from HE7F material.
[0015] Preferably, in the above preparation method, the temperature of the heat preservation stage in step S2 is 1250℃; the cooling stage in step S3 is: when the temperature is reduced to 1200℃, heat preservation treatment is performed for 30-120 minutes, and when the temperature is further reduced to 1160℃, heat preservation treatment is performed for 60-120 minutes.
[0016] Specifically, in the above sintering method, the oxygen content during the heating stage is 1.5%–4% (specifically, it can be 2.0%, 2.5%, 3.0%, or 3.5%), with the balance being nitrogen; the oxygen content during the holding stage is 1.5%–4% (specifically, it can be 2.0%, 2.5%, 3.0%, or 3.5%), with the balance being nitrogen; and the oxygen content during the cooling stage is 1.5%–4% (specifically, it can be 2.0%, 2.5%, 3.0%, or 3.5%), with the balance being nitrogen. Preferably, the change in oxygen content during the cooling stage from the start of cooling to 1100°C matches the change in temperature.
[0017] Optionally, the endothermic peak characteristic temperature of the manganese-zinc soft magnetic ferrite core can be determined by thermogravimetric analysis or by other methods.
[0018] Specifically, in the above sintering method, the heating rate during the heating stage is 1.5–2.5 °C / min, specifically 1.52 °C / min, 1.6 °C / min, 1.7 °C / min, 1.83 °C / min, 1.9 °C / min, 2.03 °C / min, 2.1 °C / min, 2.2 °C / min, 2.3 °C / min, 2.4 °C / min, or 2.5 °C / min; the cooling rate during the cooling stage is 1.0–2.8 °C / min, specifically 1.1 °C / min, 1.2 °C / min, 1.33 °C / min, 1.5 °C / min, 1.7 °C / min, 1.9 °C / min, 2.05 °C / min, 2.4 °C / min, or 2.6 °C / min.
[0019] Specifically, the manganese-zinc soft magnetic ferrite core comprises the following components: Fe2O3: 68-72 wt%, Mn3O4: 21.5-25.5 wt%, ZnO: 4.5-8.5 wt%; preferably Fe2O3: 69-71 wt%, Mn3O4: 22.5-24.5 wt%, ZnO: 5.5-7.5 wt%; more preferably Fe2O3: 70.03 wt%, Mn3O4: 23.42 wt%, ZnO: 6.55 wt%.
[0020] Specifically, the manganese-zinc soft magnetic ferrite core is a PQ110 core, which has two characteristic endothermic peak temperatures, namely 550℃ and 680℃.
[0021] Specifically, the blank dimensions of the manganese-zinc soft magnetic ferrite core are: length of 100-120mm, width of 35.00-45.00mm, and height of 20.00-30.00mm.
[0022] The present invention also protects a manganese-zinc soft magnetic ferrite core prepared by the above-described sintering method.
[0023] The application of the aforementioned manganese-zinc soft magnetic ferrite core in automotive electronic systems is also within the scope of protection of this invention.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] The sintering method of the manganese-zinc soft magnetic ferrite core of the present invention involves holding the manganese-zinc soft magnetic ferrite core at its endothermic peak characteristic temperature to regulate the Fe content in the soft magnetic ferrite. 2+ with Fe 3+ The proportion of Fe was reduced. 2+ The relative content is adjusted to shift the loss valley to the high-temperature region to reduce high-temperature loss; at the same time, densification and sintering are carried out at specific temperatures to promote complete solid-phase reaction, improve grain growth uniformity, and form relatively small grains; at the same time, pores and heterogeneous phases are reduced, thereby reducing the loss of manganese-zinc soft magnetic ferrite cores under the conditions of -20 to 140℃ and 100 to 400KHz. Attached Figure Description
[0026] Figure 1 The sintering curves are for the manganese-zinc soft magnetic ferrite core in Comparative Example 1.
[0027] Figure 2 The image shows the sintering curve of the manganese-zinc soft magnetic ferrite core in Example 1.
[0028] Figure 3 The sintering curve of the manganese-zinc soft magnetic ferrite core in Example 2 is shown.
[0029] Figure 4 The image shows the sintering curve of the manganese-zinc soft magnetic ferrite core in Example 3.
[0030] Figure 5 The sintering curve of the manganese-zinc soft magnetic ferrite core in Example 4 is shown. Detailed Implementation
[0031] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.
[0032] In both the embodiments and comparative examples of this invention, PQ110 (length 110mm, width 40.00mm, height 25.00mm) pressed from HE7F material (Fe2O3: 70.03wt%, Mn3O4: 23.42wt%, ZnO: 6.55wt%) was used as the blank. By analyzing the TGA curve of the PQ110 magnetic core, it was determined that it exhibits endothermic peaks at 550℃ and 680℃, respectively, that is, the characteristic temperatures of the absorption peaks are 550℃ and 680℃.
[0033] Example 1
[0034] A sintering method for a manganese-zinc soft magnetic ferrite core includes powder preparation, pressing, and sintering. The sintering process specifically includes the following steps (the temperature and oxygen content changes over time during the sintering process as shown in the curves). Figure 2 As shown):
[0035] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the green body is heated from room temperature to 550℃ and held for 60 minutes, then heated to 680℃ and held for 60 minutes, and then heated to 1250℃ (densification temperature is 1100~1200℃, and the oxygen content during densification is 0.3%).
[0036] S2. Heat preservation stage: Maintain the temperature at 1250℃, control the oxygen content at 3.5% (the balance is nitrogen), and sinter for 7 hours;
[0037] S3. Cooling stage: After sintering, cool down and hold at 1200℃ for 60 minutes, then continue to cool down to 1160℃ and hold for 60 minutes.
[0038] Testing revealed that the density of the manganese-zinc soft magnetic ferrite core prepared by the above sintering method was 4.88 g / cm³. 3 .
[0039] Example 2
[0040] A sintering method for a manganese-zinc soft magnetic ferrite core includes powder preparation, pressing, and sintering. The sintering process specifically includes the following steps (the temperature and oxygen content changes over time during the sintering process as shown in the curves). Figure 3 As shown):
[0041] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the green body is heated from room temperature to 550℃ and held for 60 minutes, then heated to 680℃ and held for 60 minutes, and then heated to 1250℃ (densification temperature is 1100~1200℃, and the oxygen content during densification is 0.3%).
[0042] S2. Heat preservation stage: Maintain the temperature at 1250℃, control the oxygen content at 3.0% (the balance is nitrogen), and sinter for 7 hours;
[0043] S3. Cooling stage: After sintering, cool down and hold at 1200℃ for 60 minutes, then continue to cool down to 1160℃ and hold for 60 minutes.
[0044] Testing revealed that the density of the manganese-zinc soft magnetic ferrite core prepared by the above sintering method was 4.88 g / cm³. 3 .
[0045] Example 3
[0046] A sintering method for a manganese-zinc soft magnetic ferrite core includes powder preparation, pressing, and sintering. The sintering process specifically includes the following steps (the temperature and oxygen content changes over time during the sintering process as shown in the curves). Figure 4 As shown):
[0047] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the green body is heated from room temperature to 550℃ and held for 60 minutes, then heated to 680℃ and held for 60 minutes, and then heated to 1250℃ (densification temperature is 1100~1200℃, and the oxygen content during densification is 0.3%).
[0048] S2. Heat preservation stage: Maintain the temperature at 1250℃, control the oxygen content at 2.5% (the balance is nitrogen), and sinter for 7 hours;
[0049] S3. Cooling stage: After sintering, cool down and hold at 1200℃ for 60 minutes, then continue to cool down to 1160℃ and hold for 60 minutes.
[0050] The density of the manganese-zinc soft magnetic ferrite core prepared by the above sintering method was tested to be 4.87 g / cm³. 3 .
[0051] Example 4
[0052] A sintering method for a manganese-zinc soft magnetic ferrite core includes powder preparation, pressing, and sintering. The sintering process specifically includes the following steps (the temperature and oxygen content changes over time during the sintering process as shown in the curves). Figure 5 As shown):
[0053] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the green body is heated from room temperature to 550℃ and held for 60 minutes, then heated to 680℃ and held for 60 minutes, and then heated to 1250℃ (densification temperature is 1100~1200℃, and the oxygen content during densification is 0.3%).
[0054] S2. Heat preservation stage: Maintain the temperature at 1250℃, control the oxygen content at 2.0% (the balance is nitrogen), and sinter for 7 hours;
[0055] S3. Cooling stage: After sintering, cool down and hold at 1200℃ for 60 minutes, then continue to cool down to 1160℃ and hold for 60 minutes.
[0056] The density of the manganese-zinc soft magnetic ferrite core prepared by the above sintering method was tested to be 4.87 g / cm³. 3 .
[0057] Comparative Example 1
[0058] A sintering method for a manganese-zinc soft magnetic ferrite core includes powder preparation, pressing, and sintering. The sintering process specifically includes the following steps (the temperature and oxygen content changes over time during the sintering process as shown in the curves). Figure 1 As shown):
[0059] S1. Heating stage: In a mixed atmosphere of nitrogen and oxygen, the green body is heated from room temperature to 1330℃ (densification temperature is 900~1100℃);
[0060] S2. Heat preservation stage: Maintain the temperature at 1330℃, control the oxygen content at 5.0% (the balance is nitrogen), and sinter for 6 hours;
[0061] S3. Cooling stage: After sintering, the temperature is lowered to room temperature.
[0062] Testing revealed that the density of the manganese-zinc soft magnetic ferrite core prepared by the above sintering method was 4.85 g / cm³. 3 .
[0063] Performance testing
[0064] The performance of the manganese-zinc soft magnetic ferrite cores in Examples 1-4 and Comparative Example 1 was tested using a CH2335+WL3866B instrument to detect core loss. The test results are shown in Tables 1-4.
[0065] Table 1 shows the power consumption of broadband, wide-temperature, low-loss soft magnetic materials at different temperatures (100 kHz, 200 mT) in each embodiment and comparative example.
[0066]
[0067] Table 2 shows the power consumption of broadband, wide-temperature, low-loss soft magnetic materials at different temperatures (200 kHz, 100 mT) in each embodiment and comparative example.
[0068]
[0069] Table 3 shows the power consumption of broadband, wide-temperature, low-loss soft magnetic materials at different temperatures (300 kHz, 100 mT) in each embodiment and comparative example.
[0070]
[0071]
[0072] Table 4 shows the power consumption of broadband, wide-temperature, low-loss soft magnetic materials at different temperatures (400 kHz, 100 mT) in each embodiment and comparative example.
[0073]
[0074] According to the data in Tables 1-4, the manganese-zinc soft magnetic ferrite cores prepared by the sintering methods in Examples 1-4 exhibit low power consumption in the temperature range of -40 to 160°C under different frequencies (100-400 kHz) and different saturation magnetic flux densities (100-200 mT). However, the manganese-zinc soft magnetic ferrite cores prepared by the sintering method in Comparative Example 1 have significantly higher power consumption under the same conditions than those in Examples 1-4. This indicates that the sintering method of the present invention can not only improve the sintering density of large-size manganese-zinc soft magnetic ferrite cores, but also effectively reduce their maximum sintering temperature and high-frequency power consumption.
[0075] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A sintering method of a manganese-zinc soft magnetic ferrite core comprising powdering, press forming, and sintering, characterized by, The sintering process includes the following steps: S1. Heating Stage: In a nitrogen and oxygen mixed atmosphere, the manganese-zinc soft magnetic ferrite core is held at its endothermic peak characteristic temperature for 55-65 minutes to regulate the Fe content in the soft magnetic ferrite. 2+ with Fe 3+ The proportion of Fe was reduced. 2+ The relative content, and then the temperature is raised to 1100℃ to begin densification, then to 1200℃, and then the temperature is further raised to 1245~1255℃; S2. Heat preservation stage: Sintering and shaping at 1245~1255℃; S3. Cooling stage: When the temperature drops to 1195~1205℃, keep it at that temperature for 30~120min, and continue to cool it to 1155~1165℃, then keep it at that temperature for 60~120min. The specific steps for holding the manganese-zinc soft magnetic ferrite core at its endothermic peak characteristic temperature for 55-65 minutes are as follows: hold the manganese-zinc soft magnetic ferrite core at 550℃ for 60 minutes, then raise the temperature to 680℃ and hold it for 60 minutes. The manganese-zinc soft magnetic ferrite core comprises the following components: Fe2O3: 68~72wt%, Mn3O4: 21.5~25.5wt%, ZnO: 4.5~8.5wt%.
2. The sintering method according to claim 1, wherein The oxygen content during the heat preservation stage is 1.5% to 4%, with the remainder being nitrogen.
3. The sintering method according to claim 1, wherein During the cooling phase, from the start of cooling to 1100℃, the oxygen content is 1.5% to 4%, with the remainder being nitrogen.
4. The sintering method of claim 1, wherein The endothermic peak characteristic temperature of the manganese-zinc soft magnetic ferrite core was determined by thermogravimetric analysis.
5. The sintering method of claim 1, wherein The heating rate during the heating stage is 1.5~2.5 / min℃.
6. The sintering method of claim 1, wherein The cooling rate during the cooling phase is 1.0~2.8 / min℃.
7. The sintering method of the Mn-Zn soft magnetic ferrite core according to claim 1, characterized by, The length of the blank is 100~120mm, the width is 35.00~45.00mm, and the height is 20.00~30.00mm.
8. A manganese-zinc soft magnetic ferrite core prepared by the sintering method according to any one of claims 1 to 7.
9. The application of the manganese-zinc soft magnetic ferrite core of claim 8 in an automotive electronic system.