CN102976737A - Method for improving intrinsic coercive force of permanent magnetic ferrite - Google Patents
Method for improving intrinsic coercive force of permanent magnetic ferrite Download PDFInfo
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- CN102976737A CN102976737A CN2012105529864A CN201210552986A CN102976737A CN 102976737 A CN102976737 A CN 102976737A CN 2012105529864 A CN2012105529864 A CN 2012105529864A CN 201210552986 A CN201210552986 A CN 201210552986A CN 102976737 A CN102976737 A CN 102976737A
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- kaolin
- alukalin
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- ball milling
- hcj
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Abstract
The invention discloses a method for improving intrinsic coercive force of a permanent magnetic ferrite. At the ball milling stage for manufacturing the permanent magnetic ferrite, a kaolin raw material is substituted by active kaolin; and the adding quantity of the active kaolin is 0.2 to 0.5wt% of the weight of the main raw materials. The active kaolin is obtained by adopting the following processing method: (1) ball milling; (2) acid washing: soaking the kaolin raw material powder of which the average granularity is less than or equal to 50 microns into an acid solution for at least 50 minutes; and (3) cleaning: washing the acid-washed kaolin raw material powder. The active kaolin is used in the method, and the surface of the active kaolin is porous and uneven due to erosion of the acid solution, so that the surface area is greatly increased; and in the magnet sintering process, a thin layer of fusible eutectic can be generated on the surface of crystal grains at a low sintering temperature (more than 600 DEG C), and the growth of the permanent magnetic ferrite crystal grains can be inhibited at a wide temperature interval, so that the intrinsic coercive force of a magnet is improved.
Description
Technical field
The present invention relates to a kind of method that improves the permanent-magnet ferrite HCJ.
Background technology
The existing method that improves permanent-magnet ferrite HCJ Hcj mainly is independent in the ball milling stage of making permanent-magnet ferrite or mixes and add aluminum oxide, chromic oxide, kaolin.
Add in aluminum oxide, chromic oxide, the kaolinic situation in independent or mixing, magnet HCJ Hcj improves constantly along with the increase of addition, but when the gross weight of these Material Additions surpasses the 0.3wt% of permanent-magnet ferrite main raw material weight, the remanent magnetism of permanent-magnet ferrite can obviously reduce, therefore, separately or mix and add aluminum oxide, chromic oxide, kaolin are difficult to make magnet in the situation that obtains high HCJ Hcj over-all properties Effective Raise.
Summary of the invention
Technical problem to be solved by this invention is, a kind of method that improves the permanent-magnet ferrite HCJ is provided, and the method is obviously to improve the HCJ of permanent-magnet ferrite in the situation that does not reduce permanent magnetic ferrite residual magnetization.
The technical scheme that the present invention solves its technical problem employing is: a kind of method that improves the permanent-magnet ferrite HCJ, in the ball milling stage of making permanent-magnet ferrite, use the feed kaolin of former use instead alukalin, the addition of described alukalin is the 0.2wt%-0.5wt% of main raw material weight; Described alukalin adopts following working method to obtain:
(1) ball milling: with the feed kaolin ball milling of former use to mean particle size≤50 μ m;
(2) pickling: place acidic solution to soak at least 50 minutes in the feed kaolin powder of mean particle size≤50 μ m;
(3) clean: the feed kaolin powder to pickling is washed, the feed kaolin powder that will soak in acidic solution places clear water to stir more than 15 minutes, then the weight ratio of clear water and feed kaolin filters greater than 10:1, and Air drying obtains the alukalin powder.
Further, in the described step (2), the used acidic solution of pickling is massfraction 8-15%(preferred 10%) dilute sulphuric acid, soak time is 60-70 minute.
Further, in the described step (2), the used acidic solution of pickling is massfraction 12-20%(preferred 15%) dilute hydrochloric acid, soak time is 60-70 minute.
Further, in the described step (3), the feed kaolin powder that will soak in acidic solution places clear water to stir more than 20 minutes, and the weight ratio of clear water and feed kaolin is greater than 15:1.
Kaolin is a kind of common additives of permanent-magnet ferrite material, it is in the permanent-magnet ferrite material sintering process, can generate the meltable eutectic of skim at grain surface, have the at high temperature effect of (1000 ℃-1200 ℃) prevention permanent-magnet ferrite grain growth, thereby hinder HCJ Hcj because of the strong downward trend of the raising of sintering temperature.
The present invention uses described alukalin instead, its surface is because the erosion of acidic solution, be vesicular, uneven, surface-area significantly increases, and it is in the magnet sintering process, at (more than 600 ℃) under the lower sintering temperature, just can generate the meltable eutectic of skim at grain surface, can in wider temperature range, suppress the permanent-magnet ferrite grain growth, thereby further improve magnet HCJ Hcj.
Embodiment
The invention will be further described below in conjunction with embodiment.
Embodiment 1
The operational path that present embodiment adopts is: choose and consist of SrO5.95Fe
2O
3Permanent ferrite prefiring material powder 1000g as main raw material, the formulation material of interpolation is 6g calcium carbonate, 2.5g alukalin; Described alukalin adopts following working method to obtain:
(1) ball milling: with the feed kaolin ball milling of former use to mean particle size 12 μ m;
(2) pickling: the feed kaolin powder of mean particle size 12 μ m is placed the dilute sulphuric acid of massfraction 10%, soaked 60 minutes;
(3) clean: the feed kaolin powder to pickling is washed, the feed kaolin powder that will soak in acidic solution places clear water to stir 20 minutes, clear water and kaolinic weight ratio are 20:1, filter, and Air drying obtains the alukalin powder.
Main raw material and formulation material are added in the ball mill, add water 1500g, it is the slip of 0.8 μ m that ball milling becomes mean particle size, and it is 32wt% that the slurry filtration that ball milling is good is precipitated to water content; Slip is injected mould, is that extrusion forming is the cake of diameter of phi 30.1mm under the condition of 530kA/m in magneticstrength; The moulding green compact that are pressed into are put into sintering electrical kiln sintering, and the temperature rise rate of electrical kiln is 3 ℃/min, at 1180 ℃ of lower sintering 120min; Will be through the up and down two surfacings polishing of the cake of oversintering.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result sees Table 1.
Embodiment 2
Adopt main raw material and the essentially identical technique identical with embodiment 1, distinguish and only be that the formulation material calcium carbonate that adds is that 6g, alukalin are 5g when ball milling; The working method of described alukalin is with embodiment 1.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result is referring to table 1.
Embodiment 3
Adopt main raw material and the essentially identical technique identical with embodiment 1, distinguish and only be that the formulation material calcium carbonate that adds is that 6g, alukalin are 2.5g when ball milling; Described alukalin adopts following working method to obtain:
(1) ball milling: with the feed kaolin ball milling of former use to mean particle size 8 μ m;
(2) pickling: the kaolin powder of mean particle size 8 μ m is placed the dilute hydrochloric acid of massfraction 15%, soaked 60 minutes;
(3) clean: the feed kaolin powder to pickling is washed, the feed kaolin powder that will soak in acidic solution places clear water to stir 20 minutes, clear water and kaolinic weight ratio are 20:1, filter, and Air drying obtains the alukalin powder.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result is referring to table 1.
Comparative Examples 1
Adopt main raw material and the essentially identical technique identical with embodiment 1, difference only is that the formulation material calcium carbonate that adds is that 6g, kaolin are 2.5g when ball milling, and it is identical to prepare the feed kaolin that alukalin adopts among described kaolin and the embodiment 1.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result is referring to table 1.
Comparative Examples 2
Adopt main raw material and the essentially identical technique identical with embodiment 1, difference only is that the formulation material calcium carbonate that adds is that 6g, kaolin are 5g when ball milling, and it is identical to prepare the feed kaolin that alukalin adopts among described kaolin and the embodiment 1.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result is referring to table 1.
Comparative Examples 3
Adopt main raw material and the essentially identical technique identical with embodiment 1, difference only is, the formulation material calcium carbonate that adds when ball milling is that 6g, kaolin are that 2.5g, aluminum oxide are that 1.5g, chromic oxide are 1.0g, and the feed kaolin that the preparation alukalin adopts among described kaolin and the embodiment 1 is identical.
Adopt TYU-2000 type auto measurement equipment for magnetic material that the magnetic property of the product that makes is tested, test result is referring to table 1.
Table 1
| ? | Br（mT） | Hcb（kA/m） | Hcj（kA/m） | (BH)max（kJ/m3） |
| Comparative Examples 1 | 396.8 | 286.3 | 301.7 | 28.1 |
| Comparative Examples 2 | 389.2 | 281.5 | 322.7 | 27.1 |
| Comparative Examples 3 | 384.2 | 278.6 | 323.6 | 26.5 |
| Embodiment 1 | 397.4 | 290.7 | 320.1 | 28.4 |
| Embodiment 2 | 397.3 | 291.5 | 334.7 | 28.4 |
| Embodiment 3 | 397.7 | 293 | 326.6 | 28.5 |
Compare with Comparative Examples 1, add among the embodiment 1 that the Hcj of magnet has improved 18.4 kA/m behind the alukalin, add among the embodiment 2 that the Hcj of magnet has improved 33.0kA/m behind the alukalin, add among the embodiment 3 that the Hcj of magnet has improved 24.9kA/m behind the alukalin.
Compare with Comparative Examples 2, add among the embodiment 2 that the Hcj of magnet has improved 12.0kA/m behind the alukalin, the Br of magnet improves 8.1mT.
Compare with Comparative Examples 3, add among the embodiment 2 that the Hcj of magnet has improved 11.1kA/m behind the alukalin, the Br of magnet improves 13.1mT.
In sum, utilize the present invention, adding alukalin can in the situation that does not reduce magnet remanent magnetism, significantly improve the HCJ of permanent-magnet ferrite.
Claims (4)
1. a method that improves the permanent-magnet ferrite HCJ is characterized in that, in the ball milling stage of making permanent-magnet ferrite, uses the feed kaolin of former use instead alukalin; The addition of described alukalin is the 0.2wt%-0.5wt% of main raw material weight; Described alukalin adopts following working method to obtain:
(1) ball milling: with the feed kaolin ball milling of former use to mean particle size≤50 μ m;
(2) pickling: place acidic solution to soak at least 50 minutes in the feed kaolin powder of mean particle size≤50 μ m;
(3) clean: the feed kaolin powder to pickling is washed, the feed kaolin powder that will soak in acidic solution places clear water to stir more than 15 minutes, then the weight ratio of clear water and feed kaolin filters greater than 10:1, and Air drying obtains the alukalin powder.
2. the method for raising permanent-magnet ferrite HCJ according to claim 1 is characterized in that, in the described step (2), the used acidic solution of pickling is the dilute sulphuric acid of massfraction 8-15%, and soak time is 60-70 minute.
3. the method for raising permanent-magnet ferrite HCJ according to claim 1 is characterized in that, in the described step (2), the used acidic solution of pickling is the dilute hydrochloric acid of massfraction 12-20%, and soak time is 60-70 minute.
4. the method for raising permanent-magnet ferrite HCJ according to claim 1 and 2, it is characterized in that, in the described step (3), the feed kaolin powder that will soak in acidic solution places clear water to stir more than 20 minutes, and the weight ratio of clear water and feed kaolin is greater than 15:1.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112500148A (en) * | 2020-11-27 | 2021-03-16 | 天长市中德电子有限公司 | Preparation method of high-coercivity strontium ferrite magnetic material |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101700974A (en) * | 2009-12-07 | 2010-05-05 | 湖南航天磁电有限责任公司 | Carbon-containing sintered permanent magnetic ferrite and fabrication method thereof |
| CN102436899A (en) * | 2011-12-27 | 2012-05-02 | 湖南航天磁电有限责任公司 | Ferrite magnetic material and manufacturing method thereof |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101700974A (en) * | 2009-12-07 | 2010-05-05 | 湖南航天磁电有限责任公司 | Carbon-containing sintered permanent magnetic ferrite and fabrication method thereof |
| CN102436899A (en) * | 2011-12-27 | 2012-05-02 | 湖南航天磁电有限责任公司 | Ferrite magnetic material and manufacturing method thereof |
Non-Patent Citations (3)
| Title |
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| 周鹏 等: "添加剂与永磁铁氧体的磁性能", 《江西有色金属》, vol. 21, no. 1, 31 May 2007 (2007-05-31) * |
| 李仲庆: "高矫顽力永磁铁氧体的试制与添加剂的选择", 《磁性材料及器件》, vol. 29, no. 2, 31 December 1998 (1998-12-31) * |
| 李茹民 等: "添加剂对天然磁铁矿直接合成永磁铁氧体的影响", 《哈尔滨工程大学学报》, vol. 23, no. 3, 30 June 2002 (2002-06-30) * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112500148A (en) * | 2020-11-27 | 2021-03-16 | 天长市中德电子有限公司 | Preparation method of high-coercivity strontium ferrite magnetic material |
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