CN107986772B - Manganese-zinc ferrite magnetic ring with high magnetic conductivity and preparation method thereof - Google Patents
Manganese-zinc ferrite magnetic ring with high magnetic conductivity and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a preparation method of a manganese-zinc ferrite magnetic ring with high magnetic permeability, which comprises the following steps: selecting manganese-zinc material powder with magnetic conductivity of 12000-13000, and determining the position of two peaks of the powder; adding 0.1-1% of zinc stearate into the powder, and mixing and pressing to obtain a blank; pre-sintering the blank obtained by pressing; adding zirconium balls and water into the presintered blank to perform burr ball milling, and then cleaning and airing; sintering the ball-milled blank in a sagger filled with a pad and surrounded with a cooked blank gasket; sintering the blank at the process conditions of the sagger degree of 1370-1400 ℃, the heat preservation time of 6-8 hours and the oxygen partial pressure of 7-20%, and then cooling to normal temperature in stages under the protection of nitrogen to obtain a primary finished product. Correspondingly, the invention also provides a manganese zinc ferrite magnetic ring with high magnetic conductivity. By adopting the invention, finished products with high magnetic conductivity and small inductance fluctuation can be prepared, and the yield is up to 70%.
Description
Technical Field
The invention relates to the field of special materials for electronic equipment, in particular to a magnetic material, and more particularly relates to a manganese-zinc ferrite magnetic ring with high magnetic permeability.
Background
With the increasingly competitive market of electronic products, the requirement for consistency of the products is higher. For a manganese-zinc material product which is a common material of electronic products, the manganese-zinc material product has the advantages of high requirement on magnetic permeability (ui), narrow range of inductance (AL) and the like. For manganese zinc material products with ui of 7000-10000, the inductance tolerance of the inductance AL is usually ± 25%, and for manganese zinc material products with ui of 12000 or more, the inductance tolerance can exceed ± 25%. The product of the application can meet the following requirements: when Al is 3100 +/-8%, if the product is prepared by a normal process, the yield is lower than 30%, and the difficulty is quite high.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation method of a manganese-zinc ferrite magnetic ring with high magnetic conductivity, which can prepare a finished product with high magnetic conductivity and small inductance fluctuation, and the finished product rate is up to 70%.
The invention aims to solve the technical problem of providing a manganese-zinc ferrite magnetic ring with high magnetic conductivity, wherein the magnetic conductivity reaches 12000 +/-25%, and the inductance is within a tolerance range of 3100 +/-8%.
In order to achieve the technical effect, the invention provides a manganese zinc ferrite magnetic ring with high magnetic permeability, which comprises:
step A: selecting manganese-zinc material powder with magnetic conductivity of 12000-13000, and determining the position of two peaks of the powder;
and B: adding 0.1-1% of zinc stearate into the powder obtained in the step A, and mixing and pressing to obtain a blank;
and C: b, pre-sintering the blank obtained by pressing in the step B;
step D: c, adding zirconium balls and water into the blank subjected to the pre-sintering in the step C for burr ball milling, and then cleaning and airing;
step E: sintering the ball-milled blank in a sagger filled with a pad and surrounded with a cooked blank gasket;
step F: sintering the blank placed under the process conditions that the sagger degree is 1370-1400 ℃, the heat preservation time is 6-8 hours and the oxygen partial pressure is 7% -20%, and then cooling to normal temperature in stages under the protection of nitrogen to obtain a primary finished product;
step G, testing the inductance and the temperature of the two peak points of the primary finished product;
step H, testing the primary finished product and then performing vacuum coating;
and step I, testing the inductance at 25 +/-1 ℃ and the temperature of a two-peak point after the primary finished product is subjected to vacuum coating to obtain a finished product, wherein the inductance of the finished product is within a tolerance range of 3100 +/-8% at 25 +/-1 ℃ and the temperature of the two-peak point is within a range of 23-29 ℃ under the test condition of 100KHZ 0.1V.
As a modification of the above, step F includes:
placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1380-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 0.5-1.5 hours with 7-10% oxygen content; the oxygen content of the cooling section is respectively set to be 2.5-4%, 0.5-2% and 0.01-0.4% at 1300 ℃, 1200 ℃ and 1100 ℃, and then the cooling section is cooled to the room temperature under the protection of oxygen and nitrogen.
As a modification of the above, step F includes:
placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1385-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 1-1.5 hours with 7-9% oxygen content; the oxygen content of the cooling section is respectively set to be 2.5-3%, 0.6-1.5% and 0.01-0.4% at 1300 ℃, 1200 ℃ and 1100 ℃, and then the cooling section is cooled to the room temperature under the protection of oxygen and nitrogen.
As an improvement of the scheme, in the step A, manganese zinc material powder with the magnetic conductivity of 12000-13000 and the two-peak temperature of 36-38 ℃ is selected.
As an improvement of the scheme, in the step B, 0.1-0.44% of zinc stearate is added into the powder in the step A, and a blank is obtained through mixing and pressing.
As an improvement of the scheme, in the step C, the blank obtained by pressing in the step B is presintered at the temperature of 720-800 ℃, and is kept warm for 2-4 hours.
And D, as an improvement of the scheme, in the step D, adding zirconium balls and water into the blank subjected to the pre-sintering in the step C in a roller with the rotation frequency of 15 HZ-10 HZ and the diameter of 20-30 cm for burr ball milling, and then cleaning and airing.
As an improvement of the above scheme, in step E: and sintering the ball-milled blank in a sagger which is filled with a blank filling sheet and is surrounded by the blank filling sheet, wherein the blank filling height of the blank is 25-30 mm, and then, the blank filling sheet with the thickness of 1-2 mm is used for sealing.
Testing inductance and two-peak temperature of the primary product, wherein the two-peak temperature of the primary product is within the range of 30-33 ℃;
and step H, when the primary finished product is subjected to vacuum coating, the insulation withstand voltage reaches 1KV/AC/1 mA.
Correspondingly, the invention also provides a manganese-zinc ferrite magnetic ring with high magnetic conductivity, which is prepared by adopting the preparation method.
The implementation of the invention has the following beneficial effects:
the invention provides a preparation method of a manganese-zinc ferrite magnetic ring with high magnetic permeability, which selects proper two-peak point powder on the material, and comprises the following steps: the method has the advantages that zinc volatilization is reduced through the steps of padding, enclosing and cover burning of the blank, the product performance consistency is improved, the qualified rate is improved, and the temperature of the magnetic core in the cover burning is ensured to be proper to the atmosphere by delaying the atmosphere of the cooling section and adjusting the oxygen partial pressure of the cooling section.
Therefore, the manganese-zinc ferrite magnetic ring with the magnetic conductivity up to 12000 +/-25% and the inductance within the tolerance range of 3100 +/-8% can be obtained by improving the process and the process method, and the manganese-zinc ferrite magnetic ring has high magnetic conductivity requirement and narrow inductance range, and has good stability and consistency when used on a mobile phone charger. Moreover, the invention ensures the finished product rate of the product by improving the whole process and technique, and the finished product rate is up to 70 percent.
Drawings
FIG. 1 is a graph of the inductance temperature of the powder of example 1 of the present invention;
FIG. 2 is a graph showing the temperature profile of the inductor after firing in example 1 of the present invention;
FIG. 3 is a graph showing the temperature profile of the inductor after vacuum coating in example 1 of the present invention;
FIG. 4 is a graph of the inductance temperature of the frit of example 2 of the present invention;
FIG. 5 is a graph showing the temperature profile of the inductor after firing in example 2 of the present invention;
FIG. 6 is a graph showing the temperature profile of the inductor after vacuum deposition in example 2 of the present invention;
FIG. 7 is a graph of the inductance temperature of the frit of example 3 of the present invention;
FIG. 8 is a graph showing the temperature profile of the inductor after firing in example 3 of the present invention;
FIG. 9 is a graph showing the temperature profile of the inductor after vacuum coating in example 3 of the present invention;
FIG. 10 is a graph showing the temperature profile of the inductor after firing in example 4 of the present invention;
FIG. 11 is a graph showing the inductance temperature after vacuum plating in example 4 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below.
In the prior art, the consistency is poor if the magnetic permeability ui is over 12000 material level. And the yield of the product is 12000, is lower than 70 percent under the condition of inductance tolerance +/-25 percent, and is lower than 30 percent if the inductance tolerance is +/-8 percent.
Therefore, the invention provides a preparation method of a manganese-zinc ferrite magnetic ring with high magnetic permeability, which is used for solving the problem that the overall qualified rate is still as high as 70% on the premise that AL is 3100 +/-8%. Specifically, the preparation method comprises the following steps:
s101: selecting manganese-zinc material powder with magnetic conductivity of 12000-13000, and determining the position of two peaks of the powder.
Preferably, the manganese zinc material powder has a two-peak temperature in the range of 36-38 ℃. The invention can test the second peak temperature point through an experimental oven, and the second peak position of the powder is determined to be about 36-38 ℃.
Controlling the second peak of the powder: the manganese-zinc ferrite magnetic core with high magnetic conductivity has the common powder production secondary peak at about 25 ℃, the secondary peak temperature point of the sintered product is controlled at 25 ℃, the inductance near the secondary peak point is most stable, once the secondary peak shifts to below 20 ℃ or above 29 ℃, the inductance changes obviously along with the temperature, the qualification rate is reduced, and meanwhile, the implied high-frequency impedance value can be seriously reduced.
The product of the invention has different requirements on the second peak of the powder, the temperature of the product can be 30-41 ℃, preferably 36-38 ℃, the second peak point of the sintered product is also controlled between 30-33 ℃, and the second peak of the product after vacuum coating is controlled between 23-29 ℃.
S102: and adding 0.1-1% of zinc stearate into the powder obtained in the step S101, and mixing and pressing to obtain a blank. Preferably, 0.1 to 0.44 percent of zinc stearate is added into the powder.
S103: pre-sintering the blank obtained by pressing in the step S102;
the pre-sintering process comprises the following steps: presintering at the temperature of 720 plus 800 ℃, and preserving heat for 2-4 hours. Preferably, the pre-sintering is performed at 740-760 ℃ and the temperature is maintained for 3 hours.
S104: and (5) adding zirconium balls and water into the blank subjected to the pre-sintering in the step S103 for burr ball milling, and then cleaning and airing.
The ball milling is preferably carried out in a roller with the rotation frequency of 15 HZ-10 HZ and the diameter of 20-30 cm, the diameter of the zirconium balls is preferably 1-5mm, and the addition amount of water is based on submerging the blank. By adopting the ball milling mode, the burrs of the blank can be completely removed, the surface of the finished product is smooth, and the quality is improved.
The cleaning can be performed by tap water, and the airing can be natural airing or air drying, and is not limited to this.
S105: sintering the ball-milled blank in a sagger filled with a pad and surrounded with a cooked blank gasket;
specifically, the blank filling height of the blank is 25-30 mm, and then a cooked blank gasket with the thickness of 1-2 mm is used for sealing.
The conventional common product sintering method is to directly stack and sinter a product on a zirconium plate, the consistency of performances at different blank placing positions is poor, particularly the consistency of the performances of a product with ui being more than 10000, but in order to realize the consistency of the performances of the product, the ball-milled blank is sintered in a sagger which is provided with a cushion and a well-surrounded blank cushion sheet, the blank loading height is 25-30 mm, and then the blank cushion sheet with the thickness of 1-2 mm is used for closely covering, so that the sintering temperature of the product in the sagger is consistent, the atmosphere is uniform, the volatilization of blank zinc is avoided, and the consistency of the product performance is greatly improved.
S106: sintering the blank placed under the process conditions that the sagger degree is 1370-1400 ℃, the heat preservation time is 6-8 hours and the oxygen partial pressure is 7% -20%, and then cooling to normal temperature in stages under the protection of nitrogen to obtain a primary finished product;
preferably, step S106 includes: placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1380-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 0.5-1.5 hours with 7-10% oxygen content; the oxygen content of the cooling section is respectively set to be 2.5-4%, 0.5-2% and 0.01-0.4% at 1300 ℃, 1200 ℃ and 1100 ℃, and then the cooling section is cooled to the room temperature under the protection of oxygen and nitrogen.
More preferably, step S106 includes: placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1385-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 1-1.5 hours with 7-9% oxygen content; the oxygen content of the cooling section is respectively set to be 2.5-3%, 0.6-1.5% and 0.01-0.4% at 1300 ℃, 1200 ℃ and 1100 ℃, and then the cooling section is cooled to the room temperature under the protection of oxygen and nitrogen.
The oxygen partial pressure of the cooling section is adjusted according to the two peaks of the powder, so that the two peaks of the sintered product are controlled to be 30-33 ℃, and the high-permeability product is effectively ensured to have small inductance fluctuation and high yield.
And S107, testing the inductance and the temperature of the secondary peak of the primary finished product, keeping the inductance constant for 1-2 hours, wherein the temperature of the secondary peak of the primary finished product is within the range of 30-33 ℃.
Specifically, the constant temperature of the product after being sintered and taken out of the kiln is 1-2 hours to test the inductance, and the inductance is within the tolerance range of 3100 +/-10% at 25 +/-1 ℃ under the test condition of 100KHZ 0.1V, so that the first-time qualification rate reaches 70-80%. After firing, the temperature of the two peak points is reduced from 30-41 ℃ to 30-33 ℃.
And S108, testing the primary finished product, and then performing vacuum Coating (Parylene Coating) to ensure that the insulation withstand voltage reaches 1KV/AC/1 mA.
And S109, testing the inductance at 25 +/-1 ℃ after the primary finished product is subjected to vacuum coating, wherein the spraying qualification rate is up to 95% within a tolerance range of 3100 +/-8% at 25 +/-1 ℃ under the test condition of 100KHZ 0.1V.
And performing a second peak test after vacuum coating of the primary product, wherein the temperature of a second peak point is reduced to 23-29 ℃ from 30-33 ℃ before coating, and the inductance is relatively stable at about 25 ℃.
In summary, the invention provides a preparation method of a manganese zinc ferrite magnetic ring with high magnetic permeability, which selects proper two-peak point powder material on the material, and comprises the following steps: the method has the advantages that zinc volatilization is reduced through the steps of padding, enclosing and cover burning of the blank, the product performance consistency is improved, the qualified rate is improved, and the temperature of the magnetic core in the cover burning is ensured to be proper to the atmosphere by delaying the atmosphere of the cooling section and adjusting the oxygen partial pressure of the cooling section.
Through the improvement of the process method, the manganese-zinc ferrite magnetic ring with the magnetic conductivity of 12000 +/-25 percent and the inductance within the tolerance range of 3100 +/-8 percent can be obtained, the magnetic conductivity requirement of the manganese-zinc ferrite magnetic ring is high, the inductance range is narrow, and when the manganese-zinc ferrite magnetic ring is used on a mobile phone charger, the product has good stability and consistency. Moreover, the invention ensures the finished product rate of the product by improving the whole process and technique, and the finished product rate is up to 70 percent.
When the invention is used for manufacturing the manganese-zinc ferrite magnetic ring with the AL within the tolerance range of 3100 +/-25%, the yield is up to 90%.
When the preparation method and the prior art are used for manufacturing products with the same requirements, the qualification rates of the two are shown in the table I:
| item | AL＝3100±25％ | AL＝3100±8％ |
| Percent of pass in the prior art | About 70 percent | ＜30％ |
| Percent of pass of the invention | ＞90％ | ＞70％ |
Correspondingly, the invention also provides a manganese-zinc ferrite magnetic ring with high magnetic conductivity, which is prepared by adopting the preparation method. The magnetic conductivity of the manganese-zinc ferrite magnetic ring is 12000 +/-25%, and the AL value tolerance range is as follows: AL 3100 ± 8%, 100KHZ 0.1V.
The invention is further illustrated by the following specific examples
Example 1
1. Selecting materials: selecting manganese-zinc material powder with magnetic permeability of 12000-13000, and determining the position of a secondary peak of the powder, wherein the secondary peak of the powder is 37 degrees as shown in figure 1;
2. adding 0.2% of zinc stearate into the selected powder, mixing and pressing to form a blank;
3. presintering the pressed blank in a kiln with a bell jar kiln set at the temperature of 720 ℃, and preserving heat for 3 hours;
4. adding the pre-sintered blank into a roller with the rotation frequency of 15HZ and the diameter of 20cm, adding the blank, zirconium balls and water, performing burr ball milling, cleaning by tap water, and then drying by a fan;
5. putting the ball-milled blank into a sagger which is padded and surrounded by a cooked blank pad for sintering, wherein the blank loading height of the blank is 25-27 mm; then, a blank is closely covered by a cooked blank gasket with the thickness of 2 mm;
6. placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1388 ℃ of a heat preservation section, air sintering for 6 hours of the heat preservation section and sintering for 1 hour of 8 percent oxygen content; the oxygen content of 1300 ℃, 1200 ℃ and 1100 ℃ in the cooling section is respectively set to be 3%, 1.2% and 0.25%, and then the cooling is carried out to the room temperature under a certain proportion of oxygen and nitrogen;
7. testing the inductance at constant temperature for 2 hours after the product is sintered and discharged from the kiln, and controlling the bare-loop single-turn inductance to be AL 3100-3400 under the condition of 100KHZ 0.1V; the first pass percent is 75 percent;
8. coating pre-bimodal temperature points: as shown in fig. 2, the peak point is at 33 degrees;
9. sending the tested product to Parylene Coating, wherein the film thickness is required to be 0.020-0.025 mm, and AL is 2900-3300 nH;
10. after the Coating returns, the inductance of the product is measured completely, the internal control AL is 3100 +/-6%, and the spraying qualification rate is 96%;
11. the bimodal test was carried out after Parylene Coating: as shown in fig. 3, the peak is reduced from 33 degrees before Coating to 25 degrees, and the inductance is relatively stable around 25 degrees.
Example 2:
1. selecting materials: selecting manganese-zinc material powder with the magnetic permeability of 12000-13000, and determining the position of a second peak of the powder, wherein the second peak of the powder is 33 degrees and the second peak of the powder is close to the front as shown in figure 4.
2. Adding 0.2% of zinc stearate into the selected powder, mixing and pressing to form a blank;
3. presintering the pressed blank in a kiln with a bell jar kiln set at the temperature of 750 ℃, and preserving heat for 3 hours;
4. adding the pre-sintered blank into a roller with the rotation frequency of 15HZ and the diameter of 20cm, adding the blank, zirconium balls and water, performing burr ball milling, cleaning by tap water, and then drying by a fan;
5. putting the ball-milled blank into a sagger which is padded and surrounded by a cooked blank pad for sintering, wherein the blank loading height of the blank is 25-28 mm; then, a blank is closely covered by a cooked blank gasket with the thickness of 2 mm;
6. placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1385 ℃ of a heat preservation section, air sintering for 7 hours of the heat preservation section and sintering for 1 hour of 8 percent oxygen content; considering that the two peaks of the batch are close to each other, the oxygen contents of 1300 ℃, 1200 ℃ and 1100 ℃ in the cooling section need to be adjusted to be respectively set to be 3%, 1.4% and 0.35%, and then the batch is cooled to the room temperature under the certain proportion of oxygen and nitrogen.
7. Testing the inductance at constant temperature for 2 hours after the product is sintered and discharged from the kiln, and controlling the bare-loop single-turn inductance to be AL 3100-3400 under the condition of 100KHZ 0.1V; the first pass percent is 76%.
8. Coating pre-bimodal temperature points: as shown in FIG. 5, the peak point has been controlled to about 33 degrees by adjusting the oxygen content through the cooling section.
9. The tested product is sent to Parylene Coating, the film thickness is required to be 0.020-0.025 mm, and AL is 2900-3300 nH.
10. After the Coating returns, the inductance of the product is measured completely, the internal control AL is 3100 +/-6%, and the spraying qualification rate is 98%.
11. The bimodal test was carried out after Parylene Coating: as shown in FIG. 6, the peak two is reduced from 33 degrees before Coating to 23-29 degrees, and the inductance is relatively stable around 25 degrees.
Example 3
1. Selecting materials: selecting manganese-zinc material powder with magnetic conductivity of 12000-13000, and determining the position of a second peak of the powder, wherein the second peak of the powder is 39-41 degrees and is behind the second peak of the powder as shown in figure 7;
2. adding 0.2% of zinc stearate into the selected powder, mixing and pressing to form a blank;
3. presintering the pressed blank in a kiln with a bell jar kiln set at 800 ℃, and preserving heat for 3 hours;
4. adding the pre-sintered blank into a roller with the rotation frequency of 15HZ and the diameter of 20cm, adding the blank, zirconium balls and water, performing burr ball milling, cleaning by tap water, and then drying by a fan;
5. putting the ball-milled blank into a sagger which is filled with a cushion and surrounded with a blank gasket to be sintered, wherein the blank filling height of the blank is 26-29 mm, and then, closely covering the blank with the blank gasket with the thickness of 2 mm;
6. placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1380 ℃ of a heat preservation section, air sintering for 8 hours of the heat preservation section and sintering for 1 hour of 8 percent oxygen content; considering that the oxygen content of 1300 ℃, 1200 ℃ and 1100 ℃ in the cooling section needs to be adjusted after two peaks of the batch are close, the oxygen content is respectively set to be 2.5%, 0.. 8% and 0.18%, and then the batch is cooled to the room temperature under a certain proportion of oxygen and nitrogen.
7. Testing the inductance at constant temperature for 2 hours after the products are sintered and discharged from the kiln, and controlling the bare loop single-turn inductance to be AL 2900-3200 under the condition of 100KHZ 0.1V; the first pass percent is 75 percent.
8. Coating pre-bimodal temperature points: as shown in FIG. 8, the peak point has been controlled to about 33 degrees by adjusting the oxygen content through the cooling section.
9. Sending the tested product to Parylene Coating, wherein the film thickness is required to be 0.020-0.025 mm, and AL is 2900-3300 nH
10. After the Coating returns, the inductance of the product is measured completely, the internal control AL is 3100 +/-6%, and the spraying qualification rate is 97.5%.
11. The bimodal test was carried out after Parylene Coating: as shown in FIG. 9, the peak two is reduced from 33 degrees before Coating to 23-29 degrees, and the inductance is relatively stable around 25 degrees.
From the above three examples, it can be seen that the target product T5.8 × 3 × 2.2 is produced from the above three kinds of two-peak powders, and the performance can reach the target requirement only by sintering according to the corresponding sintering process conditions.
Comparative example 1:
in the production of the powder with the large production normal two peaks of 25 degrees, as shown in fig. 10, the two peaks after T5.8 x 3 x 2.2 sintering are at 25 degrees, but the two peaks after Coating are severely shifted to about 17 degrees (as shown in fig. 11), so that the inductance is rapidly changed along with the temperature change in the vicinity of 25 degrees, and the inductance is poor.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (6)
1. A preparation method of a manganese zinc ferrite magnetic ring with high magnetic permeability is characterized by comprising the following steps:
step A: selecting manganese-zinc material powder with magnetic conductivity of 12000-13000 and a second-peak temperature of 36-38 ℃, and determining the second-peak position of the powder;
and B: adding 0.1-1% of zinc stearate into the powder obtained in the step A, and mixing and pressing to obtain a blank;
and C: pre-sintering the blank obtained by pressing in the step B at the temperature of 720-800 ℃, and preserving heat for 2-4 hours;
step D: c, adding zirconium balls and water into the blank subjected to the pre-sintering in the step C for burr ball milling, and then cleaning and airing;
step E: sintering the ball-milled blank in a sagger which is padded and surrounded by a blank filling sheet, wherein the blank filling height of the blank is 25-30 mm, and then, closely covering the blank filling sheet with the thickness of 1-2 mm;
step F: placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1380-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 0.5-1.5 hours with 7-10% oxygen content; setting oxygen contents of 1300 ℃, 1200 ℃ and 1100 ℃ in the cooling section to be 2.5-4%, 0.5-2% and 0.01-0.4% respectively, and then cooling to room temperature under the protection of oxygen and nitrogen to obtain a primary finished product;
step G, testing the inductance and the temperature of the two peak points of the primary finished product;
step H, testing the primary finished product and then performing vacuum coating;
and step I, testing the inductance at 25 +/-1 ℃ and the temperature of a two-peak point after the primary finished product is subjected to vacuum coating to obtain a finished product, wherein the inductance of the finished product is within a tolerance range of 3100 +/-8% at 25 +/-1 ℃ and the temperature of the two-peak point is within a range of 23-29 ℃ under the test condition of 100KHZ 0.1V.
2. The method of making a high permeability manganese-zinc-ferrite magnetic ring as claimed in claim 1, wherein step F comprises:
placing the sagger with the placed blank into a bell jar kiln, and sintering under the process conditions of 1385-1390 ℃ heat preservation section, air sintering 6-8 hours heat preservation section and sintering 1-1.5 hours with 7-9% oxygen content; the oxygen content of the cooling section is respectively set to be 2.5-3%, 0.6-1.5% and 0.01-0.4% at 1300 ℃, 1200 ℃ and 1100 ℃, and then the cooling section is cooled to the room temperature under the protection of oxygen and nitrogen.
3. The method for preparing a manganese-zinc-ferrite magnetic ring with high magnetic permeability as claimed in claim 1, wherein in step B, 0.1% -0.44% of zinc stearate is added to the powder in step A, and a blank is obtained by mixing and pressing.
4. The method for preparing a manganese-zinc-ferrite magnetic ring with high magnetic permeability as claimed in claim 1, wherein in the step D, zirconium balls and water are added into the blank pre-sintered in the step C in a roller with the rotation frequency of 15 Hz-10 Hz and the diameter of 20-30 cm for burr ball milling, and then the blank is cleaned and dried.
5. The method for preparing a manganese-zinc-ferrite magnetic ring with high magnetic permeability as claimed in claim 1, wherein, in step G, the primary finished product is tested for inductance and peak point temperature, and the peak point temperature of the primary finished product is within the range of 30-33 ℃;
and step H, when the primary finished product is subjected to vacuum coating, the insulation withstand voltage reaches 1KV/AC/1 mA.
6. A manganese-zinc-ferrite magnetic ring with high magnetic permeability, characterized in that it is prepared by the preparation method of any one of claims 1 to 5.
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