JP7494608B2 - Powder magnetic core and manufacturing method thereof - Google Patents
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- 239000000843 powder Substances 0.000 title claims description 123
- 238000004519 manufacturing process Methods 0.000 title claims description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 337
- 229910052742 iron Inorganic materials 0.000 claims description 160
- 239000006249 magnetic particle Substances 0.000 claims description 90
- 239000002245 particle Substances 0.000 claims description 76
- 239000000314 lubricant Substances 0.000 claims description 49
- 239000000203 mixture Substances 0.000 claims description 33
- 239000006247 magnetic powder Substances 0.000 claims description 31
- 238000000576 coating method Methods 0.000 claims description 24
- 239000011248 coating agent Substances 0.000 claims description 23
- 238000000465 moulding Methods 0.000 claims description 22
- 229910052751 metal Inorganic materials 0.000 claims description 21
- 239000002184 metal Substances 0.000 claims description 21
- 239000000428 dust Substances 0.000 claims description 20
- -1 phosphate compound Chemical class 0.000 claims description 15
- 229910019142 PO4 Inorganic materials 0.000 claims description 14
- 239000010452 phosphate Substances 0.000 claims description 14
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 9
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 9
- 229910052749 magnesium Inorganic materials 0.000 claims description 9
- 239000011777 magnesium Substances 0.000 claims description 9
- 239000011701 zinc Substances 0.000 claims description 9
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 8
- 229910052788 barium Inorganic materials 0.000 claims description 8
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 8
- 229910052744 lithium Inorganic materials 0.000 claims description 8
- 229910052725 zinc Inorganic materials 0.000 claims description 8
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 7
- 229910052791 calcium Inorganic materials 0.000 claims description 7
- 239000011575 calcium Substances 0.000 claims description 7
- 230000035699 permeability Effects 0.000 description 25
- 235000014113 dietary fatty acids Nutrition 0.000 description 13
- 239000000194 fatty acid Substances 0.000 description 13
- 229930195729 fatty acid Natural products 0.000 description 13
- 150000004665 fatty acids Chemical class 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 10
- 150000003839 salts Chemical class 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 238000007906 compression Methods 0.000 description 7
- 230000006835 compression Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- AGXUVMPSUKZYDT-UHFFFAOYSA-L barium(2+);octadecanoate Chemical group [Ba+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O AGXUVMPSUKZYDT-UHFFFAOYSA-L 0.000 description 6
- 230000004907 flux Effects 0.000 description 6
- 239000011800 void material Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 5
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical class [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- ULQISTXYYBZJSJ-UHFFFAOYSA-N 12-hydroxyoctadecanoic acid Chemical compound CCCCCCC(O)CCCCCCCCCCC(O)=O ULQISTXYYBZJSJ-UHFFFAOYSA-N 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 150000001408 amides Chemical class 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- UKMSUNONTOPOIO-UHFFFAOYSA-N docosanoic acid Chemical compound CCCCCCCCCCCCCCCCCCCCCC(O)=O UKMSUNONTOPOIO-UHFFFAOYSA-N 0.000 description 2
- POULHZVOKOAJMA-UHFFFAOYSA-N dodecanoic acid Chemical compound CCCCCCCCCCCC(O)=O POULHZVOKOAJMA-UHFFFAOYSA-N 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- IPCSVZSSVZVIGE-UHFFFAOYSA-N hexadecanoic acid Chemical compound CCCCCCCCCCCCCCCC(O)=O IPCSVZSSVZVIGE-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- UTOPWMOLSKOLTQ-UHFFFAOYSA-N octacosanoic acid Chemical compound CCCCCCCCCCCCCCCCCCCCCCCCCCCC(O)=O UTOPWMOLSKOLTQ-UHFFFAOYSA-N 0.000 description 2
- 229920002050 silicone resin Polymers 0.000 description 2
- 239000001993 wax Substances 0.000 description 2
- 229940114072 12-hydroxystearic acid Drugs 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 235000021357 Behenic acid Nutrition 0.000 description 1
- 229910017082 Fe-Si Inorganic materials 0.000 description 1
- 229910017133 Fe—Si Inorganic materials 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000005639 Lauric acid Substances 0.000 description 1
- 235000021314 Palmitic acid Nutrition 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229940116226 behenic acid Drugs 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 239000001506 calcium phosphate Substances 0.000 description 1
- 229910000389 calcium phosphate Inorganic materials 0.000 description 1
- 235000011010 calcium phosphates Nutrition 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- CPSYWNLKRDURMG-UHFFFAOYSA-L hydron;manganese(2+);phosphate Chemical compound [Mn+2].OP([O-])([O-])=O CPSYWNLKRDURMG-UHFFFAOYSA-L 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910000398 iron phosphate Inorganic materials 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 229940033355 lauric acid Drugs 0.000 description 1
- HGPXWXLYXNVULB-UHFFFAOYSA-M lithium stearate Chemical compound [Li+].CCCCCCCCCCCCCCCCCC([O-])=O HGPXWXLYXNVULB-UHFFFAOYSA-M 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- WQEPLUUGTLDZJY-UHFFFAOYSA-N n-Pentadecanoic acid Natural products CCCCCCCCCCCCCCC(O)=O WQEPLUUGTLDZJY-UHFFFAOYSA-N 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 229940098695 palmitic acid Drugs 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910000889 permalloy Inorganic materials 0.000 description 1
- 150000003014 phosphoric acid esters Chemical class 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000004043 responsiveness Effects 0.000 description 1
- WBHHMMIMDMUBKC-XLNAKTSKSA-N ricinelaidic acid Chemical compound CCCCCC[C@@H](O)C\C=C\CCCCCCCC(O)=O WBHHMMIMDMUBKC-XLNAKTSKSA-N 0.000 description 1
- 229960003656 ricinoleic acid Drugs 0.000 description 1
- FEUQNCSVHBHROZ-UHFFFAOYSA-N ricinoleic acid Natural products CCCCCCC(O[Si](C)(C)C)CC=CCCCCCCCC(=O)OC FEUQNCSVHBHROZ-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 229910000702 sendust Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 229960004274 stearic acid Drugs 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- TUNFSRHWOTWDNC-HKGQFRNVSA-N tetradecanoic acid Chemical compound CCCCCCCCCCCCC[14C](O)=O TUNFSRHWOTWDNC-HKGQFRNVSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 1
- 229910000165 zinc phosphate Inorganic materials 0.000 description 1
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- Powder Metallurgy (AREA)
- Soft Magnetic Materials (AREA)
- Electromagnets (AREA)
Description
本発明の一実施形態は、圧粉磁心及びその製造方法に関する。 One embodiment of the present invention relates to a powder magnetic core and a method for manufacturing the same.
鉄粉等の軟磁性粉末を圧縮成形して得られる圧粉磁心は、形状自由度が高く、磁心形状の設計範囲が広いという利点がある。また、圧粉磁心は、製造工程での材料歩留まりがよく、材料コストを低減可能であるという利点を有している。
このような利点から、圧粉磁心は、変圧器、リアクトル、サイリスタバルブ、ノイズフィルタ、チョークコイル等に用いられている。また、圧粉磁心は、モータ用鉄心、一般家電及び産業機器用モータのロータ及びヨーク、さらには、ディーゼルエンジン及びガソリンエンジンの電子制御式燃料噴射装置に組み込まれる電磁弁用のソレノイドコア（固定鉄心）等、各種軟質磁気部品への適用が進んでいる。
Powder cores obtained by compression molding soft magnetic powder such as iron powder have the advantage of having a high degree of freedom in shape and a wide range of design options for the magnetic core shape. In addition, powder cores have the advantage of having a high material yield in the manufacturing process and being able to reduce material costs.
Due to these advantages, powder magnetic cores are used in transformers, reactors, thyristor valves, noise filters, choke coils, etc. Powder magnetic cores are also increasingly being applied to various soft magnetic parts, such as motor cores, rotors and yokes of motors for general home appliances and industrial equipment, and solenoid cores (stationary iron cores) for solenoid valves incorporated in electronically controlled fuel injection devices for diesel engines and gasoline engines.
特許文献１には、良好な直流重畳特性と高い比抵抗を有するリアクトル用複合軟磁性材料として、絶縁被膜により被覆された軟磁性粉末をシリコーン樹脂で被覆して得た被覆粉末と、ＳｉＯ２等の無機絶縁粉末とを均一に混合し、その混合物を成形し、５００℃以上で焼成することで複合軟磁性材料を得ることが提案されている。特許文献１の複合軟磁性材料では、シリコーン樹脂と無機絶縁粉末とからなる絶縁層の偏析厚さを制御することで、良好な直流重畳特性と高い比抵抗を得ようとしている。 Patent Document 1 proposes that, as a composite soft magnetic material for reactors having good DC superposition characteristics and high resistivity, a composite soft magnetic material is obtained by uniformly mixing a coated powder obtained by coating a soft magnetic powder coated with an insulating film with a silicone resin and an inorganic insulating powder such as SiO2 , molding the mixture, and firing it at 500° C. or higher. The composite soft magnetic material of Patent Document 1 aims to obtain good DC superposition characteristics and high resistivity by controlling the segregation thickness of the insulating layer consisting of the silicone resin and the inorganic insulating powder.
鉄損Ｗは、渦電流損Ｗｅとヒステリシス損Ｗｈの和であり、周波数ｆ、励磁磁束密度Ｂｍ、固有抵抗値ρ、材料の厚みｔとしたとき、渦電流損Ｗｅは下記式１、ヒステリシス損Ｗｈは下記式２のように表されることから、鉄損Ｗは下記式３のように表される。なお、ｋ１、ｋ２は係数である。
Ｗｅ＝（ｋ１Ｂｍ
２ｔ２／ρ）ｆ２ （式１）
Ｗｈ＝ｋ２Ｂｍ
１．６ｆ （式２）
Ｗ＝Ｗｅ＋Ｗｈ＝（ｋ１Ｂｍ
２ｔ２／ρ）ｆ２＋ｋ２Ｂｍ
１．６ｆ （式３）
Iron loss W is the sum of eddy current loss We and hysteresis loss Wh, and when the frequency is f, the excitation magnetic flux density Bm , the specific resistance value ρ, and the thickness of the material is t, the eddy current loss We is expressed by the following formula 1, and the hysteresis loss Wh is expressed by the following formula 2, so that iron loss W is expressed by the following formula 3. Note that k1 and k2 are coefficients.
We = (k1B m 2 t 2 /ρ) f 2 (Equation 1)
Wh = k2B m 1.6 f (Equation 2)
W = We + Wh = (k1B m 2 t 2 /ρ) f 2 + k2B m 1.6 f (Equation 3)
渦電流損Ｗｅは、式１のように周波数ｆの二乗に比例して増大する。このため、鉄損Ｗは、式３のような数百ｋＨｚから数ＭＨｚのような高周波数領域では渦電流損Ｗｅの影響がきわめて大きくなるため、鉄損Ｗにおけるヒステリシス損Ｗｈの影響は相対的に小さくなる。このため高周波数領域では、固有抵抗値ρを大きくして渦電流損Ｗｅを低減させることが最優先で重要である。
モータの大出力化等に伴い、リアクトル等のコアは、大電流、高磁場側での使用が求められるようになっている。このようなリアクトル用コアにおいては、高磁場側でも微分透磁率が低下しないこと、すなわち恒透磁率（使用環境による透磁率の変化）に優れることが望ましい。そのため、リアクトル用圧粉磁心はより小粒子径の軟磁性粉末を用いること、より厚い絶縁被膜を被覆することが多い。
The eddy current loss We increases in proportion to the square of the frequency f as shown in Equation 1. For this reason, the influence of the eddy current loss We on the iron loss W becomes extremely large in the high frequency range of several hundred kHz to several MHz as shown in Equation 3, and the influence of the hysteresis loss Wh on the iron loss W becomes relatively small. For this reason, in the high frequency range, it is important and first priority to increase the specific resistance value ρ to reduce the eddy current loss We.
As motors become more powerful, cores for reactors and the like are required to be used in high current and high magnetic fields. It is desirable for such reactor cores to have excellent constant permeability (changes in permeability due to the usage environment) that does not decrease even in high magnetic fields. For this reason, reactor powder cores often use soft magnetic powder with smaller particle diameters and are coated with thicker insulating coatings.
近年、センサ用途でも、数百ｋＨｚから数ＭＨｚのような高周波数領域での利用は増えている。高周波数領域でのセンサ応答性を向上させるために、高複素透磁率材料は望ましい。複素透磁率は、材料中に発生する磁束密度Ｂを、材料に印加した交流磁界Ｈで割ったものである。 In recent years, the use of high-frequency ranges, such as several hundred kHz to several MHz, has been increasing even in sensor applications. To improve sensor responsiveness in the high-frequency range, high complex permeability materials are desirable. Complex permeability is the magnetic flux density B generated in a material divided by the alternating magnetic field H applied to the material.
本発明の一目的は、高周波数領域で使用する低鉄損で高複素透磁率の圧粉磁心を提供することである。 One object of the present invention is to provide a powder magnetic core with low core loss and high complex permeability for use in the high frequency range.
本発明の一実施形態は、以下の通りである。
［１］平均粒子径が６０μｍ～１５０μｍである鉄基軟磁性粒子と、前記鉄基軟磁性粒子の外周部分に形成される空隙部とを含み、前記空隙部は、前記鉄基軟磁性粒子の外周全長に対し５０％以上の部分において、幅０．４μｍ～４．０μｍである、圧粉磁心。
［２］前記鉄基軟磁性粒子は純鉄粒子を含む、［１］に記載の圧粉磁心。
［３］前記鉄基軟磁性粒子は、表面に絶縁性被膜が形成された絶縁性被覆鉄基軟磁性粒子を含む、［１］又は［２］に記載の圧粉磁心。
［４］前記絶縁性被覆鉄基軟磁性粒子の絶縁性被膜は、リン酸塩化合物を含む、［３］に記載の圧粉磁心。
［５］前記絶縁性被覆鉄基軟磁性粒子の外周部分に、更に絶縁成分を含む、［３］又は［４］に記載の圧粉磁心。
［６］前記絶縁成分は、バリウム、カルシウム、リチウム、マグネシウム、及び亜鉛からなる群より選ばれる少なくとも１種の金属の絶縁成分を含む、［５］に記載の圧粉磁心。
［７］位置センサ用圧粉磁心又はアクチュエータ用圧粉磁心である、［１］から［６］のいずれかに記載の圧粉磁心。
［８］１０ｋＨｚ～５００ｋＨｚの周波数領域で用いる位置センサ用圧粉磁心である、［１］から［７］のいずれかに記載の圧粉磁心。
One embodiment of the present invention is as follows.
[1] A powder magnetic core comprising iron-based soft magnetic particles having an average particle size of 60 μm to 150 μm, and voids formed in outer circumferential portions of the iron-based soft magnetic particles, the voids having a width of 0.4 μm to 4.0 μm in a portion that is 50% or more of the total circumferential length of the iron-based soft magnetic particles.
[2] The powder magnetic core according to [1], wherein the iron-based soft magnetic particles include pure iron particles.
[3] The powder magnetic core according to [1] or [2], wherein the iron-based soft magnetic particles include insulating-coated iron-based soft magnetic particles having an insulating coating formed on the surface thereof.
[4] The powder magnetic core according to [3], wherein the insulating coating of the insulating-coated iron-based soft magnetic particles contains a phosphate compound.
[5] The powder magnetic core according to [3] or [4], further comprising an insulating component in the outer peripheral portion of the insulating coated iron-based soft magnetic particles.
[6] The powder magnetic core according to [5], wherein the insulating component includes an insulating component of at least one metal selected from the group consisting of barium, calcium, lithium, magnesium, and zinc.
[7] The powder magnetic core according to any one of [1] to [6], which is a powder magnetic core for a position sensor or a powder magnetic core for an actuator.
[8] The powder magnetic core according to any one of [1] to [7], which is a powder magnetic core for a position sensor used in a frequency range of 10 kHz to 500 kHz.
［９］平均粒子径が６０μｍ～１５０μｍである鉄基軟磁性粉末と、前記鉄基軟磁性粉末１００質量部に対し０．５質量部以上２．０質量部未満の潤滑剤粉末とを含む粉末混合物に、７００ＭＰａ以上の成形圧力を加えて圧粉体に成形すること、及び、前記圧粉体を２００℃～４５０℃で熱処理することを含む、圧粉磁心の製造方法。
［１０］前記鉄基軟磁性粉末は純鉄粉末を含む、［９］に記載の圧粉磁心の製造方法。
［１１］前記鉄基軟磁性粉末は、表面に絶縁性被膜が形成された絶縁性被覆鉄基軟磁性粒子を含む、［９］又は［１０］に記載の圧粉磁心の製造方法。
［１２］前記絶縁性被覆鉄基軟磁性粒子の絶縁性被膜は、リン酸塩化合物を含む、［１１］に記載の圧粉磁心の製造方法。
［１３］前記潤滑剤粉末は絶縁成分を含む、［９］から［１２］のいずれかに記載の圧粉磁心の製造方法。
［１４］前記絶縁成分は、バリウム、カルシウム、リチウム、マグネシウム、及び亜鉛からなる群より選ばれる少なくとも１種の金属の絶縁成分を含む、［１３］に記載の圧粉磁心の製造方法。
[9] A method for producing a powder core, comprising: applying a molding pressure of 700 MPa or more to a powder mixture containing an iron-based soft magnetic powder having an average particle size of 60 μm to 150 μm and a lubricant powder of 0.5 parts by mass or more and less than 2.0 parts by mass per 100 parts by mass of the iron-based soft magnetic powder, and molding the powder mixture into a green compact; and heat treating the green compact at 200° C. to 450° C.
[10] The method for producing a dust core according to [9], wherein the iron-based soft magnetic powder contains pure iron powder.
[11] The method for producing a dust core according to [9] or [10], wherein the iron-based soft magnetic powder includes insulating coated iron-based soft magnetic particles having an insulating coating formed on the surface thereof.
[12] The method for producing a dust core according to [11], wherein the insulating coating of the insulating-coated iron-based soft magnetic particles contains a phosphate compound.
[13] The method for producing a dust core according to any one of [9] to [12], wherein the lubricant powder contains an insulating component.
[14] The method for producing a powder magnetic core according to [13], wherein the insulating component includes an insulating component of at least one metal selected from the group consisting of barium, calcium, lithium, magnesium, and zinc.
一実施形態によれば、低鉄損で高複素透磁率の圧粉磁心を提供することができる。この圧粉磁心を用いて、高周波数領域において適するセンサを提供することができる。 According to one embodiment, a powder magnetic core with low core loss and high complex permeability can be provided. Using this powder magnetic core, a sensor suitable for use in the high frequency range can be provided.
以下、本発明の一実施形態について説明するが、以下の例示によって本発明は限定されない。 One embodiment of the present invention will be described below, but the present invention is not limited to the following examples.
（圧粉磁心）
一実施形態による圧粉磁心としては、平均粒子径が６０～１５０μｍである鉄基軟磁性粒子と、鉄基軟磁性粒子の外周部分に形成される空隙部とを含み、空隙部は、鉄基軟磁性粒子の外周全長に対し５０％以上の部分において、幅０．４μｍ以上４．０μｍ以下であることを特徴とする。
これによれば、低鉄損で高複素透磁率の圧粉磁心を提供することができる。
(Powder magnetic core)
A powder magnetic core according to one embodiment includes iron-based soft magnetic particles having an average particle size of 60 to 150 μm, and voids formed in the outer periphery of the iron-based soft magnetic particles, the voids having a width of 0.4 μm to 4.0 μm over a portion that is 50% or more of the total outer periphery of the iron-based soft magnetic particles.
This makes it possible to provide a powder magnetic core with low core loss and high complex permeability.
一実施形態による圧粉磁心は、鉄基軟磁性粒子と、鉄基軟磁性粒子の外周部分に形成される空隙部とを含むことができる。
圧粉磁心は、原料としての鉄基軟磁性粉末を圧粉成形して得ることができ、好ましくは圧粉成形後に鉄基軟磁性粒子が焼結を開始する温度未満で熱処理して得ることができる。
このようにして得られる圧粉磁心は、原料としての鉄基軟磁性粉末に由来して、鉄基軟磁性粒子と、鉄基軟磁性粒子間に介在する空隙部とを含む。鉄基軟磁性粒子間の界面は、緊密に接している部分もあり得るし、線状の隙間を介在して対向する部分もあり得る。さらには、原料の潤滑剤粉末等に由来して、鉄基軟磁性粒子の外周部分には大きい空隙部が形成されることもあり得る。また、圧粉磁心には、複数の鉄基軟磁性粒子に囲まれた比較的大きな空隙部が形成されることもあり得る。
圧粉磁心において、鉄基軟磁性粒子の外周部分に形成される空隙部には、潤滑剤粉末等に由来して潤滑剤成分等の絶縁成分が含まれることもある。また、鉄基軟磁性粒子の表面に絶縁性被膜等が形成される場合では、圧粉磁心において、鉄基軟磁性粒子の外周部分に形成される空隙部には、絶縁性被膜等に由来して絶縁性成分が含まれることもある。
A dust core according to an embodiment can include iron-based soft magnetic particles and voids formed in the outer periphery of the iron-based soft magnetic particles.
The dust core can be obtained by compacting iron-based soft magnetic powder as a raw material, and preferably by heat treating the powder after compacting at a temperature lower than the temperature at which the iron-based soft magnetic particles start to sinter.
The dust core thus obtained contains iron-based soft magnetic particles and voids between the iron-based soft magnetic particles, originating from the iron-based soft magnetic powder as a raw material. The interface between the iron-based soft magnetic particles may be in close contact with each other in some parts, or may be opposed to each other with a linear gap between them in other parts. Furthermore, large voids may be formed in the outer periphery of the iron-based soft magnetic particles, originating from the lubricant powder of the raw material, etc. Furthermore, the dust core may have a relatively large void surrounded by a plurality of iron-based soft magnetic particles.
In the dust core, the voids formed in the outer periphery of the iron-based soft magnetic particles may contain insulating components such as lubricant components derived from the lubricant powder, etc. In addition, in the case where an insulating coating or the like is formed on the surface of the iron-based soft magnetic particles, in the dust core, the voids formed in the outer periphery of the iron-based soft magnetic particles may contain insulating components derived from the insulating coating, etc.
圧粉磁心において、空隙部は、鉄基軟磁性粒子の外周全長に対し５０％以上の部分において、幅０．４μｍ以上４．０μｍ以下であることが好ましい。以下、鉄基軟磁性粒子の外周全長に対し空隙部の幅が０．４μｍ以上４．０μｍ以下となる割合を数値Ａ（％）とも記す。
数値Ａは５０％以上が好ましく、６０％以上がより好ましく、８０％以上がさらに好ましい。鉄基軟磁性粒子の外周部分に、大きな空隙部が存在する割合が少ないことで、複素透磁率の低下を抑制することができる。一実施形態では、比較的大粒子径の鉄基軟磁性粒子を用いるため、粒子内で渦電流損が発生して鉄損が増大する傾向があるが、数値Ａを５０％以上に制御することで、ヒステリシス損の上昇を抑制して、全体の鉄損を低くすることができる。
数値Ａの上限値は特に制限されず、理論上は１００％が好ましいが、幅４．０μｍを超える空隙部を排除する制御が複雑になることから、９８％以下であってよく、９５％以下であってもよい。
In the powder magnetic core, the voids preferably have a width of 0.4 μm to 4.0 μm in a portion that accounts for 50% or more of the total circumferential length of the iron-based soft magnetic particles. Hereinafter, the percentage of the void width of 0.4 μm to 4.0 μm in the total circumferential length of the iron-based soft magnetic particles is also referred to as numerical value A (%).
The value A is preferably 50% or more, more preferably 60% or more, and even more preferably 80% or more. The small ratio of large voids in the outer periphery of the iron-based soft magnetic particles can suppress the decrease in complex permeability. In one embodiment, since iron-based soft magnetic particles with a relatively large particle size are used, eddy current loss occurs within the particles and iron loss tends to increase, but by controlling the value A to 50% or more, the increase in hysteresis loss can be suppressed and the overall iron loss can be reduced.
The upper limit of the numerical value A is not particularly limited, and theoretically 100% is preferable. However, since the control for eliminating voids exceeding 4.0 μm in width becomes complicated, the upper limit may be 98% or less, or may be 95% or less.
鉄基軟磁性粒子の外周部分に形成される空隙部は、幅０．４μｍ以上が好ましく、０．５ｍ以上がより好ましく、１．０μｍ以上がさらに好ましい。鉄基軟磁性粒子間が緊密に接近、又は接触すると、粒子の振動が粒子間で吸収され熱エネルギーに変換されることを一因として、鉄損が大きくなる可能性がある。そのため、鉄基軟磁性粒子間には、幅０．４μｍ以上の空隙部が介在することが好ましい。また、この空隙部に軟質の潤滑剤成分、絶縁性成分等が形成されていることで、鉄損の上昇をより抑制することができる。
鉄基軟磁性粒子の外周部分に形成される空隙部は、幅４．０μｍ以下が好ましく、３．５μｍ以下がより好ましい。これによって、密度低下を防止して、磁気特性をより高めることができる。
The width of the gap formed in the outer periphery of the iron-based soft magnetic particles is preferably 0.4 μm or more, more preferably 0.5 m or more, and even more preferably 1.0 μm or more. When the iron-based soft magnetic particles are closely close to each other or in contact with each other, the vibration of the particles is absorbed between the particles and converted into thermal energy, which may increase the iron loss. Therefore, it is preferable that the gap between the iron-based soft magnetic particles has a width of 0.4 μm or more. In addition, by forming a soft lubricant component, insulating component, etc. in this gap, the increase in iron loss can be further suppressed.
The width of the voids formed in the outer periphery of the iron-based soft magnetic particles is preferably 4.0 μm or less, and more preferably 3.5 μm or less, which can prevent a decrease in density and further improve the magnetic properties.
ここで、数値Ａの測定方法について説明する。
空隙部の幅は、鉄基軟磁性粒子の中心点から直径方向において、鉄基軟磁性粒子の表面から、隣接する鉄基軟磁性粒子の表面までの距離である。また、鉄基軟磁性粒子の中心点は、鉄基軟磁性粒子の長径と短径が交差する点とする。
隣接する鉄基軟磁性粒子の間に潤滑剤成分、絶縁性成分等が介在する場合は、これらが介在する部分は空隙部として扱う。隣接する鉄基軟磁性粒子の界面が一部結合して空隙部を介さない場合は、一部結合している部分の空隙部の幅は０μｍとして扱う。
Here, a method for measuring the value A will be described.
The width of the void is the distance from the surface of the iron-based soft magnetic particle to the surface of the adjacent iron-based soft magnetic particle in the diameter direction from the center point of the iron-based soft magnetic particle. The center point of the iron-based soft magnetic particle is defined as the point where the major axis and minor axis of the iron-based soft magnetic particle intersect.
When a lubricant component, insulating component, etc. is present between adjacent iron-based soft magnetic particles, the portion where these are present is treated as a void. When the interface between adjacent iron-based soft magnetic particles is partially bonded and does not include a void, the width of the void in the partially bonded portion is treated as 0 μm.
数値Ａは、以下の手順で測定することができる。
圧粉磁心の断面を顕微鏡によって観察し、倍率Ｚ１００Ｘ１０００＝１００００倍でサイズが１６００ｍｍ×１２００ｍｍの写真画像を得る。全周長が撮影されている粒子をランダムで一個を選ぶ。この粒子と隣の粒子との間の空隙の幅を測定する。幅が０．４μｍ以上４．０μｍ以下であれば、その部分の空隙に対応する粒子の外周の長さを測定する。上記測定した長さを全周長で割った数値を数値Ａ（％）とする。この操作を複数個の粒子で行って平均して数値Ａ（％）を求めるとよい。
The value A can be measured by the following procedure.
The cross section of the powder magnetic core is observed under a microscope to obtain a photographic image of 1600 mm x 1200 mm in size at a magnification of Z100 x 1000 = 10,000 times. Randomly select one particle whose perimeter is photographed. Measure the width of the gap between this particle and the adjacent particle. If the width is 0.4 μm or more and 4.0 μm or less, measure the outer perimeter of the particle corresponding to the gap in that portion. The value obtained by dividing the measured length by the perimeter is taken as value A (%). This operation can be performed on multiple particles and averaged to obtain value A (%).
鉄基軟磁性粒子の平均粒子径は、６０μｍ～１５０μｍが好ましい。
鉄基軟磁性粒子の平均粒子径は、６０μｍ以上が好ましく、６５μｍ以上がより好ましく、７０μｍ以上がさらに好ましい。より微小な粒子では渦電流損を低減し、低鉄損の材料を得ることができる。一方、一実施形態では、鉄基軟磁性粒子の平均粒子径を６０μｍ以上とすることで、鉄損が増大する傾向があるが、鉄基軟磁性粒子の外周部分の空隙部の形状を制御することで、比較的大粒子径の鉄基軟磁性粒子であっても鉄損の増大を抑制することができる。このような圧粉磁心は、低鉄損かつ高複素透磁率の用途に好ましく用いることができる。
鉄基軟磁性粒子の平均粒子径は、１５０μｍ以下が好ましく、１００μｍ以下がより好ましく、８０μｍ以下がさらに好ましい。これによって、粒子内の渦電流損を低減して、鉄損の増大を抑制することができる。
The average particle size of the iron-based soft magnetic particles is preferably 60 μm to 150 μm.
The average particle size of the iron-based soft magnetic particles is preferably 60 μm or more, more preferably 65 μm or more, and even more preferably 70 μm or more. Smaller particles can reduce eddy current loss and obtain a material with low iron loss. On the other hand, in one embodiment, by setting the average particle size of the iron-based soft magnetic particles to 60 μm or more, the iron loss tends to increase, but by controlling the shape of the voids in the outer periphery of the iron-based soft magnetic particles, the increase in iron loss can be suppressed even for iron-based soft magnetic particles with a relatively large particle size. Such a dust core can be preferably used for applications requiring low iron loss and high complex permeability.
The average particle size of the iron-based soft magnetic particles is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less, which can reduce eddy current loss within the particles and suppress an increase in iron loss.
ここで、平均粒子径は、面積基準の平均粒子径である。例えば、鉄基軟磁性粒子の平均粒子径は、上記した数値Ａの測定手順と同様にして写真画像を得て、観察される３個の粒子について、長径及び短径を測定し、（長径＋短径）／２から粒子径を求め、３個の粒子径を平均して求めることができる。 Here, the average particle diameter is the average particle diameter based on area. For example, the average particle diameter of iron-based soft magnetic particles can be determined by obtaining a photographic image in the same manner as in the measurement procedure for Value A described above, measuring the major axis and minor axis of three particles observed, calculating the particle diameter from (major axis + minor axis)/2, and averaging the three particle diameters.
鉄基軟磁性粒子としては、鉄基及び鉄合金基のいずれであってもよい。
圧粉磁心の全体組成は、鉄を主成分として含むことが好ましい。例えば、圧粉磁心の全体組成に対し、鉄は、５０質量％以上が好ましく、８０質量％以上がより好ましく、９０質量％以上がさらに好ましい。
圧粉磁心の全体組成は、不可避不純物を含み得る。圧粉磁心の全体組成全量に対し、不可避不純物は、合計量として１質量％以下が好ましく、０．５質量％以下がより好ましく、０．１質量％以下がさらに好ましい。
The iron-based soft magnetic particles may be either iron-based or iron alloy-based.
The overall composition of the powder magnetic core preferably contains iron as a main component. For example, the iron content of the overall composition of the powder magnetic core is preferably 50 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
The overall composition of the powder magnetic core may contain unavoidable impurities. The total amount of the unavoidable impurities is preferably 1 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.1 mass % or less, based on the total amount of the overall composition of the powder magnetic core.
鉄基軟磁性粒子としては、例えば、純鉄粒子；Ｆｅ－Ｓｉ合金、Ｆｅ－Ａｌ合金、パーマロイ、センダスト等の鉄合金粒子等が挙げられる。磁束密度の高さや成形性等の観点から、純鉄粒子をより好ましく用いることができる。 Examples of iron-based soft magnetic particles include pure iron particles; iron alloy particles such as Fe-Si alloy, Fe-Al alloy, permalloy, and sendust. From the standpoint of high magnetic flux density and moldability, pure iron particles are more preferably used.
一実施形態による圧粉磁心は、鉄基軟磁性粒子の外周部分に絶縁成分を含むことができる。ここで、絶縁成分は、原料に添加した潤滑剤粉末、潤滑剤粉末の一部が熱分解した潤滑剤由来成分、又はこれらの組み合わせを含むことができる。
圧粉磁心において、隣接する鉄基軟磁性粒子の間に絶縁成分が介在することで、鉄損の上昇をより抑制することができる。また、一実施形態による数値Ａを満たす空隙部に絶縁成分が介在することで、過剰な絶縁成分を起因として磁束密度が低下することによる透磁率の低下を防止することができる。
The dust core according to one embodiment may include an insulating component in the outer periphery of the iron-based soft magnetic particles, where the insulating component may include a lubricant powder added to the raw material, a lubricant-derived component formed by thermally decomposing a portion of the lubricant powder, or a combination thereof.
In the powder magnetic core, the presence of insulating components between adjacent iron-based soft magnetic particles can further suppress an increase in iron loss. Also, the presence of insulating components in the voids that satisfy the numerical value A according to one embodiment can prevent a decrease in magnetic permeability due to a decrease in magnetic flux density caused by an excess of insulating components.
絶縁成分としては、潤滑剤成分であることが好ましく、具体的には脂肪酸金属塩を好ましく用いることができ、例えば、バリウム、カルシウム、リチウム、マグネシウム、亜鉛、マグネシウム、アルミニウム、ナトリウム、ストロンチウム等の金属の絶縁成分が挙げられ、より好ましくはこれらの金蔵の脂肪酸金属塩である。なかでも、バリウム、カルシウム、リチウム、マグネシウム、及び亜鉛からなる群より選ばれる少なくとも１種の金属による脂肪酸金属塩を用いることが好ましく、バリウム、リチウム、亜鉛、又はこれらの組み合わせがより好ましい。
脂肪酸金属塩を構成する脂肪酸としては、炭素数１２～２８の飽和又は不飽和の高級脂肪酸類が好ましく、例えば、ステアリン酸、１２－ヒドロキシステアリン酸、ラウリン酸、ミリスチン酸、パルミチン酸、リシノール酸、ベヘン酸、モンタン酸等が挙げられる。これらの脂肪酸の金属塩は、圧粉成形において特に好適な粉末潤滑性を示す。なかでも、ステアリン酸金属塩を好ましく用いることができる。
好ましい一例としては、ステアリン酸バリウム、ステアリン酸リチウム、ステアリン酸亜鉛、又はこれらの組み合わせである。
The insulating component is preferably a lubricant component, and specifically, a fatty acid metal salt can be preferably used, for example, an insulating component of a metal such as barium, calcium, lithium, magnesium, zinc, magnesium, aluminum, sodium, strontium, etc., and more preferably, a fatty acid metal salt of these metals. Among them, it is preferable to use a fatty acid metal salt of at least one metal selected from the group consisting of barium, calcium, lithium, magnesium, and zinc, and more preferably barium, lithium, zinc, or a combination thereof.
The fatty acid constituting the fatty acid metal salt is preferably a saturated or unsaturated higher fatty acid having 12 to 28 carbon atoms, such as stearic acid, 12-hydroxystearic acid, lauric acid, myristic acid, palmitic acid, ricinoleic acid, behenic acid, montanic acid, etc. Metal salts of these fatty acids exhibit particularly suitable powder lubricity in powder compaction. Among them, metal stearates can be preferably used.
A preferred example is barium stearate, lithium stearate, zinc stearate, or a combination thereof.
上記した脂肪酸金属塩は、１種単独で、又は２種以上を組み合わせて用いてもよい。脂肪酸金属塩に加えて、又はこれに変えて、潤滑剤成分としてアミドワックス等のその他の潤滑剤成分を用いてもよい。この場合、上記した脂肪酸金属塩は、潤滑剤成分全量に対し０．１質量％以上であることが好ましい。 The fatty acid metal salts described above may be used alone or in combination of two or more. In addition to or instead of the fatty acid metal salts, other lubricant components such as amide wax may be used as lubricant components. In this case, the fatty acid metal salts described above are preferably present in an amount of 0.1 mass% or more based on the total amount of the lubricant components.
潤滑剤成分は、鉄基軟磁性粒子１００質量部に対し、０．５質量部以上が好ましく、０．７質量部以上がより好ましく、１．０質量部以上がさらに好ましくい。これによって、圧粉磁心において、鉄基軟磁性粒子間の空隙部の形状をより好ましく制御することができ、鉄損をより低減することができる。また、潤滑剤成分が成形体に適度に配合されるため、成形体の充填性が高まり、鉄基軟磁性粒子間の空隙部の形状をより好ましく制御することができる。また、成形体の充填性が高まることで、磁束密度を高めてより高透磁率化することができる。
潤滑剤成分は、鉄基軟磁性粒子１００質量部に対し、２．０質量部未満が好ましく、１．７質量部以下がより好ましく、１．５質量部以下がさらに好ましい。これによって、圧粉磁心全体に対し鉄基軟磁性粒子の占積率を適度に維持して、透磁率の過剰な低下を防止することができる。
潤滑剤成分を含む絶縁成分は、鉄基軟磁性粒子１００質量部に対して０．５質量部以上が好ましく、０．７質量部以上がより好ましく、及び／又は２．０質量部未満が好ましい。
The lubricant component is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and even more preferably 1.0 parts by mass or more, per 100 parts by mass of the iron-based soft magnetic particles. This allows the shape of the voids between the iron-based soft magnetic particles in the powder magnetic core to be more preferably controlled, and the iron loss to be further reduced. In addition, since the lubricant component is appropriately blended into the compact, the filling property of the compact is improved, and the shape of the voids between the iron-based soft magnetic particles can be more preferably controlled. In addition, the improved filling property of the compact increases the magnetic flux density and increases the magnetic permeability.
The amount of the lubricant component is preferably less than 2.0 parts by mass, more preferably 1.7 parts by mass or less, and even more preferably 1.5 parts by mass or less, per 100 parts by mass of the iron-based soft magnetic particles, which allows the space factor of the iron-based soft magnetic particles to be appropriately maintained in the entire powder magnetic core, and prevents an excessive decrease in magnetic permeability.
The insulating component including the lubricant component is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and/or preferably less than 2.0 parts by mass, per 100 parts by mass of the iron-based soft magnetic particles.
鉄基軟磁性粒子としては、表面に絶縁性被膜が形成された絶縁性被覆鉄基軟磁性粒子を用いることができる。
圧粉磁心において、鉄基軟磁性粒子の表面に絶縁性被膜が形成されることで、渦電流損をより低減することができ、鉄損の増大をより抑制することができる。
As the iron-based soft magnetic particles, insulating coated iron-based soft magnetic particles having an insulating coating formed on the surface thereof can be used.
In the dust core, by forming an insulating coating on the surfaces of the iron-based soft magnetic particles, the eddy current loss can be further reduced, and an increase in iron loss can be further suppressed.
絶縁性被膜としては、無機絶縁性被膜であることが好ましい。絶縁性被膜としては、リン酸塩化合物が好ましく、例えば、リン酸エステル；リン酸鉄、リン酸マンガン、リン酸亜鉛、リン酸カルシウム、リン酸アルミニウム等のリン酸金属塩化合物等が挙げられる。
一方法として、リン酸塩化合物被覆鉄基軟磁性粒子は、リン酸、ホウ酸及びマグネシウムを含有する水溶液を鉄基軟磁性粉末に混合して乾燥することによって製造することができる。この場合、鉄基軟磁性粉末１ｋｇの表面に０．７～１１ｇ程度のリン酸塩化合物被膜が形成されることが好ましい。より詳しくは、特開平０９－３２０８３０号公報に記載の方法に準拠して行うことができる。
The insulating coating is preferably an inorganic insulating coating, and is preferably a phosphate compound, such as a phosphoric acid ester, or a metal phosphate compound such as iron phosphate, manganese phosphate, zinc phosphate, calcium phosphate, or aluminum phosphate.
As one method, the phosphate compound-coated iron-based soft magnetic particles can be produced by mixing an aqueous solution containing phosphoric acid, boric acid, and magnesium with an iron-based soft magnetic powder and drying the mixture. In this case, it is preferable that about 0.7 to 11 g of a phosphate compound coating is formed on the surface of 1 kg of the iron-based soft magnetic powder. More specifically, the method described in JP-A-09-320830 can be used.
一実施形態による圧粉磁心は、低鉄損かつ高複素透磁率が要求される用途に好ましく用いることができる。用途の一例としては、位置センサ用圧粉磁心、アクチュエータ用圧粉磁心等が挙げられる。また、一実施形態による圧粉磁心は、１０ｋＨｚ～５００ｋＨｚの中周波数領域での使用に適している。 The powder magnetic core according to one embodiment can be preferably used in applications requiring low core loss and high complex permeability. Examples of applications include powder magnetic cores for position sensors and powder magnetic cores for actuators. The powder magnetic core according to one embodiment is also suitable for use in the medium frequency range of 10 kHz to 500 kHz.
（圧粉磁心の製造方法）
一実施形態による圧粉磁心の製造方法としては、平均粒子径が６０μｍ～１５０μｍである鉄基軟磁性粉末と、鉄基軟磁性粉末１００質量部に対し０．５質量部以上２．０質量部未満の潤滑剤粉末とを含む粉末混合物に、７００ＭＰａ以上の成形圧力を加えて圧粉体に成形すること、及び、圧粉体を２００℃～４５０℃で熱処理することを含むことを特徴とする。
これによれば、低鉄損で高複素透磁率の圧粉磁心を提供することができる。
(Method of manufacturing powder magnetic core)
A method for producing a powder magnetic core according to one embodiment includes: applying a molding pressure of 700 MPa or more to a powder mixture containing an iron-based soft magnetic powder having an average particle size of 60 μm to 150 μm and a lubricant powder in an amount of 0.5 parts by mass or more and less than 2.0 parts by mass per 100 parts by mass of the iron-based soft magnetic powder, and molding the powder mixture into a powder compact; and heat treating the powder compact at a temperature of 200° C. to 450° C.
This makes it possible to provide a powder magnetic core with low core loss and high complex permeability.
まず、鉄基軟磁性粉末と、鉄基軟磁性粉末１００質量部に対し０．５質量部以上２．０質量部未満である潤滑剤粉末とを含む粉末混合物を用意する工程について説明する。 First, we will explain the process of preparing a powder mixture containing iron-based soft magnetic powder and lubricant powder in an amount of 0.5 parts by mass or more and less than 2.0 parts by mass per 100 parts by mass of the iron-based soft magnetic powder.
粉末混合物は、鉄基軟磁性粉末と、潤滑剤粉末とを含むことができる。
鉄基軟磁性粉末は、上記した鉄基軟磁性粒子と共通する組成及び平均粒子径を備えることが好ましい。鉄基軟磁性粉末としては、純鉄粉末を好ましく用いることができる。また、鉄基軟磁性粉末は、表面に絶縁性被膜が形成された絶縁性被覆鉄基軟磁性粉末であることが好ましい。この場合、絶縁性被膜は好ましくはリン酸塩化合物である。詳細については、上記鉄基軟磁性粒子で説明した通りである。
The powder mixture may include an iron-based soft magnetic powder and a lubricant powder.
The iron-based soft magnetic powder preferably has a composition and average particle size common to the iron-based soft magnetic particles. As the iron-based soft magnetic powder, a pure iron powder can be preferably used. The iron-based soft magnetic powder is preferably an insulating coated iron-based soft magnetic powder having an insulating coating formed on the surface. In this case, the insulating coating is preferably a phosphate compound. Details are as described above for the iron-based soft magnetic particles.
潤滑剤粉末としては、成形潤滑剤であることが好ましく、例えば、脂肪酸、脂肪酸金属塩、非金属系ワックス等が挙げられる。
好ましくは、潤滑剤粉末は、バリウム、カルシウム、リチウム、マグネシウム、及び亜鉛からなる群より選ばれる少なくとも１種の金属の絶縁成分であって、より好ましくはこれらの金属の脂肪酸金属塩である。詳細については、上記潤滑剤成分で説明した通りである。
The lubricant powder is preferably a molding lubricant, and examples thereof include fatty acids, fatty acid metal salts, and non-metallic waxes.
Preferably, the lubricant powder is an insulating component of at least one metal selected from the group consisting of barium, calcium, lithium, magnesium, and zinc, more preferably a fatty acid metal salt of these metals, as described above in detail in the lubricant component section.
潤滑剤粉末は、鉄基軟磁性粉末１００質量部に対し、０．５質量部以上が好ましく、０．７質量部以上がより好ましく、１．０質量部以上がさらに好ましい。
潤滑剤粉末は、鉄基軟磁性粉末１００質量部に対し、２．０質量部未満が好ましく、１．７質量部以下がより好ましく、１．５質量部以下がさらに好ましい。
例えば、潤滑剤粉末は、鉄基軟磁性粉末１００質量部に対し、好ましくは０．５質量部以上２．０質量部未満であり、より好ましくは０．７～１．７質量部であり、さらに好ましくは１．０～１．５質量部である。
これによって、得られる圧粉磁心において、鉄基軟磁性粒子間に適度に潤滑剤成分が介在するようになって、鉄基軟磁性粒子間の空隙部の形状をより好ましく制御することができる。
The amount of the lubricant powder is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and even more preferably 1.0 part by mass or more, per 100 parts by mass of the iron-based soft magnetic powder.
The amount of the lubricant powder is preferably less than 2.0 parts by mass, more preferably 1.7 parts by mass or less, and even more preferably 1.5 parts by mass or less, per 100 parts by mass of the iron-based soft magnetic powder.
For example, the amount of the lubricant powder is preferably 0.5 parts by mass or more and less than 2.0 parts by mass, more preferably 0.7 to 1.7 parts by mass, and even more preferably 1.0 to 1.5 parts by mass, per 100 parts by mass of the iron-based soft magnetic powder.
This allows an appropriate amount of lubricant component to be present between the iron-based soft magnetic particles in the resulting dust core, making it possible to more preferably control the shape of the voids between the iron-based soft magnetic particles.
潤滑剤粉末の平均粒子径は、これに限定されないが、２～６０μｍが好ましく、８～２５μｍがより好ましい。特に小粒子径の潤滑剤粉末を用いることで、鉄基軟磁性粉末に潤滑剤粉末をより均一に分散させることができ、得られる圧粉磁心において成分組成がより均一になり、圧粉磁心の絶縁性をより高めることができる。
ここで、平均粒子径は、体積基準の平均粒子径であり、具体的には、レーザ回折法によって測定することができる。
The average particle size of the lubricant powder is not limited to this, but is preferably 2 to 60 μm, and more preferably 8 to 25 μm. By using a lubricant powder with a particularly small particle size, the lubricant powder can be more uniformly dispersed in the iron-based soft magnetic powder, the component composition of the obtained powder core becomes more uniform, and the insulation properties of the powder core can be further improved.
Here, the average particle size is a volume-based average particle size, and specifically, can be measured by a laser diffraction method.
鉄基軟磁性粉末と潤滑剤粉末との混合方法は、特に限定されずに、通常の方法に従えばよい。粉末混合物にはその他の任意成分が配合されてもよい。 The method for mixing the iron-based soft magnetic powder and the lubricant powder is not particularly limited and may be any conventional method. Other optional components may be added to the powder mixture.
次に、７００ＭＰａ以上の成形圧力を加えて圧粉体に成形する工程について説明する。 Next, we will explain the process of forming the powder into a green compact by applying a molding pressure of 700 MPa or more.
成形は、金型、樹脂型等の成形型に、上記した粉末混合物を充填し、加圧成形することで行うことができる。
成形圧力は、７００ＭＰａ以上が好ましく、８００ＭＰａ以上がより好ましく、１０００ＭＰａ以上がさらに好ましい。これによって、圧粉体密度をより高めることができる。また、鉄基軟磁性粒子間の空隙部をより狭めることができ、圧粉体に粗大な空隙部が残らないようにすることができる。これによって、得られる圧粉磁心において空隙部が数値Ａをより好ましい範囲で満たすことが可能となる。また、一実施形態では、粉末混合物に適度の潤滑剤粉末が含まれるため、粉末混合物を７００ＭＰａ以上で加圧しても、隣り合う鉄基軟磁性粒子が直接接触することを防止し、鉄基軟磁性粒子間に適度の潤滑剤成分が形成されて、得られる圧粉磁心においてより好ましい形状の空隙部を形成可能となる。
The molding can be carried out by filling the above-mentioned powder mixture into a molding die such as a metal mold or a resin mold, and then pressing the mixture.
The molding pressure is preferably 700 MPa or more, more preferably 800 MPa or more, and even more preferably 1000 MPa or more. This can further increase the green density. In addition, the gaps between the iron-based soft magnetic particles can be narrowed, and no coarse gaps can remain in the green compact. This allows the gaps in the resulting powder core to satisfy the numerical value A in a more preferred range. In one embodiment, since the powder mixture contains an appropriate amount of lubricant powder, even if the powder mixture is pressed at 700 MPa or more, it is possible to prevent adjacent iron-based soft magnetic particles from coming into direct contact, and an appropriate amount of lubricant component is formed between the iron-based soft magnetic particles, making it possible to form gaps of a more preferred shape in the resulting powder core.
成形圧力は、２０００ＭＰａ以下が好ましく、１５００ＭＰａ以下がより好ましい。より高圧力で粉末混合物を成形すると、隣り合う鉄基軟磁性粒子間の距離が狭くなり、又は、隣り合う鉄基軟磁性粒子が直接接触するようになって、ヒステリシス損が上昇する傾向がある。そのため、成形圧力は２０００ＭＰａ以下に制限することが好ましい。 The molding pressure is preferably 2000 MPa or less, and more preferably 1500 MPa or less. If the powder mixture is molded at a higher pressure, the distance between adjacent iron-based soft magnetic particles tends to become narrower, or adjacent iron-based soft magnetic particles tend to come into direct contact with each other, which tends to increase hysteresis loss. Therefore, it is preferable to limit the molding pressure to 2000 MPa or less.
成形は、成形後の圧粉体において、鉄基軟磁性粉末の占積率が９０体積％以上が好ましく、９３体積％以上がより好ましく、９５体積％以上がさらに好ましい。
これによって、圧粉磁心において、鉄基軟磁性粒子の割合が多くなり、ある程度の透磁率を確保することができ、また、比抵抗をより高めることができる。
成形後の圧粉体において、鉄基軟磁性粉末の占積率の上限値は特に限定されずに、得られる圧粉磁心において空隙部が数値Ａを満たす範囲が好ましく、例えば、９９体積％以下が好ましく、９８体積％以下がより好ましい。
In the compact after molding, the volume fraction of the iron-based soft magnetic powder in the green compact is preferably 90 volume % or more, more preferably 93 volume % or more, and even more preferably 95 volume % or more.
This increases the proportion of iron-based soft magnetic particles in the powder magnetic core, making it possible to ensure a certain degree of magnetic permeability and further increase the resistivity.
In the compact after molding, the upper limit of the volume fraction of the iron-based soft magnetic powder is not particularly limited, and it is preferable that the voids in the obtained powder core satisfy the numerical value A. For example, the volume fraction is preferably 99% or less, and more preferably 98% or less.
成形温度は、特に制限されず、室温で行うことができる。潤滑剤の流動性を確保するために、２００℃以下の範囲で加熱下で成形してもよい。
成形時間は、特に制限されず、圧粉体のサイズ、形状、組成等に応じて適宜調節すればよい。例えば、成形時間は、１０分～２４時間でよく、３０分～１２時間でよい。
The molding temperature is not particularly limited and can be room temperature, but in order to ensure the fluidity of the lubricant, molding may be performed under heating at a temperature of 200° C. or less.
The molding time is not particularly limited and may be appropriately adjusted depending on the size, shape, composition, etc. of the green compact. For example, the molding time may be 10 minutes to 24 hours, or 30 minutes to 12 hours.
次に、圧粉体を２００℃～４５０℃で熱処理する工程について説明する。
圧粉体の熱処理温度は、２００℃以上が好ましく、２５０℃以上がより好ましく、３００℃以上がさらに好ましい。
これによって、鉄基軟磁性粒子の歪みを低減し、熱応力が緩和されることで、圧粉磁心のヒステリシス損をより低減することができる。また、鉄基軟磁性粒子間の潤滑剤成分の流動性が高まり、鉄基軟磁性粒子の外周部分の空隙部がより均等な幅を持つようになって、より好ましい範囲で数値Ａを満たす空隙部を形成可能となる。これによって、より低鉄損で、より高複素透磁率である圧粉磁心を提供することができる。
Next, the step of heat treating the powder compact at 200° C. to 450° C. will be described.
The heat treatment temperature of the powder compact is preferably 200° C. or higher, more preferably 250° C. or higher, and even more preferably 300° C. or higher.
This reduces the distortion of the iron-based soft magnetic particles and alleviates thermal stress, thereby further reducing the hysteresis loss of the powder magnetic core. In addition, the fluidity of the lubricant component between the iron-based soft magnetic particles is increased, and the voids in the outer periphery of the iron-based soft magnetic particles have a more uniform width, making it possible to form voids that satisfy the numerical value A in a more preferable range. This makes it possible to provide a powder magnetic core with lower iron loss and higher complex permeability.
圧粉体の熱処理温度は、鉄基軟磁性粒子が焼結を開始する温度未満であることが好ましい。また、圧粉体の熱処理温度は、圧粉体に含まれる潤滑剤成分が熱分解を開始する温度未満であることが好ましい。
例えば、圧粉体の熱処理温度は、４５０℃以下が好ましく、４００℃以下がより好ましい。
これによって、潤滑剤成分が熱分解することを防止して、得られる圧粉磁心において鉄基軟磁性粒子間に適度な潤滑剤成分が含まれるようにすることができる。また、潤滑剤成分が熱分解して気化することを防止して、圧粉体から潤滑剤成分が気化して除去されることで生じる比較的大きな空隙部の発生をより防止することができる。
The heat treatment temperature of the powder compact is preferably lower than the temperature at which the iron-based soft magnetic particles start to sinter, and is also preferably lower than the temperature at which the lubricant component contained in the powder compact starts to thermally decompose.
For example, the heat treatment temperature of the powder compact is preferably 450° C. or less, and more preferably 400° C. or less.
This prevents the lubricant components from being thermally decomposed, allowing the obtained powder core to contain an appropriate amount of the lubricant components between the iron-based soft magnetic particles, and also prevents the lubricant components from being thermally decomposed and vaporized, thereby more effectively preventing the generation of relatively large voids that would otherwise occur if the lubricant components were vaporized and removed from the green compact.
圧粉体の熱処理雰囲気は、特に制限されず、大気雰囲気下であってもよいが、より高温で熱処理する場合は、潤滑剤成分の熱分解を促進しないたために、窒素雰囲気等の不活性雰囲気で行うことが好ましい。圧粉体の熱処理は、特に制限されず、大気圧下で行ってもよい。
圧粉体の熱処理時間は、特に制限されず、圧粉体のサイズ、形状、組成等に応じて適宜調節すればよい。例えば、熱処理時間は、１０分～２４時間でよく、３０分～１２時間でよい。
The heat treatment atmosphere of the powder compact is not particularly limited and may be an air atmosphere, but when heat treatment is performed at a higher temperature, it is preferable to perform the heat treatment in an inert atmosphere such as a nitrogen atmosphere so as not to promote thermal decomposition of the lubricant components. The heat treatment of the powder compact is not particularly limited and may be performed under atmospheric pressure.
The heat treatment time of the powder compact is not particularly limited and may be appropriately adjusted depending on the size, shape, composition, etc. of the powder compact. For example, the heat treatment time may be 10 minutes to 24 hours, or 30 minutes to 12 hours.
一実施形態による製造方法では、得られる圧粉磁心が鉄基軟磁性粒子と、鉄基軟磁性粒子の外周部分に形成される空隙部とを含むことが好ましく、より好ましくはが鉄基軟磁性粒子の平均粒子径が６０～１５０μｍである。さらに、得られる圧粉磁心において、空隙部は、鉄基軟磁性粒子の外周全長に対し５０％以上の部分において、幅０．１μｍ以上４．０μｍ以下であることが好ましい。 In one embodiment of the manufacturing method, the resulting powder magnetic core preferably contains iron-based soft magnetic particles and voids formed in the outer periphery of the iron-based soft magnetic particles, and more preferably the average particle size of the iron-based soft magnetic particles is 60 to 150 μm. Furthermore, in the resulting powder magnetic core, it is preferable that the voids have a width of 0.1 μm to 4.0 μm in a portion that is 50% or more of the total outer periphery of the iron-based soft magnetic particles.
以下、本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
（例１）
平均粒子径が７５μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末を、円柱形状の成形金型に充填し、１２００ＭＰａの成形圧力を加えて圧縮成形し、外径１１．３ｍｍ、高さ約１０ｍｍの円柱形状の圧縮成形体を得た。
得られた圧縮成形体を窒素雰囲気下で、３００℃、１時間で、熱処理し、圧粉体を得た。
なお、原料の絶縁性被覆純鉄粉末に由来して、圧粉体には０．０５質量部程度の絶縁成分が含まれる。以下の例でも同じである。
(Example 1)
An insulating coated pure iron powder obtained by coating pure iron powder having an average particle size of 75 μm with a phosphate compound layer was filled into a cylindrical molding die and compression molded by applying a molding pressure of 1200 MPa to obtain a cylindrical compression molded body having an outer diameter of 11.3 mm and a height of approximately 10 mm.
The obtained compression molded body was heat treated in a nitrogen atmosphere at 300° C. for 1 hour to obtain a green compact.
The green compact contains about 0.05 parts by mass of an insulating component derived from the insulating-coated pure iron powder used as the raw material. The same applies to the following examples.
（例２）
平均粒子径が４５μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末１００質量部に対し、絶縁成分として平均粒子径が６μｍであるステアリン酸亜鉛０．７質量部を添加し、粉末混合物を得た。この粉末混合物を用いて圧縮成形体を得た他は、例１と同様にして、圧粉体を得た。
（例３）
例２において、平均粒子径が７５μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末を用いた他は例２と同様にして、圧粉体を得た。
（例４）
平均粒子径が７５μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末１００質量部に対し、絶縁成分として平均粒子径が８μｍであるステアリン酸バリウム１．０質量部を添加し、粉末混合物を得た。この粉末混合物を用いて圧縮成形体を得た他は、例１と同様にして、圧粉体を得た。
（例５）
平均粒子径が１６０μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末１００質量部に対し、絶縁成分として平均粒子径が２０μｍ程度であるアミド系滑剤０．７質量部を含む粉末混合物を用意した。この粉末混合物を用いて圧縮成形体を得た他は、例１と同様にして、圧粉体を得た。
(Example 2)
A powder mixture was obtained by adding 0.7 parts by mass of zinc stearate having an average particle size of 6 μm as an insulating component to 100 parts by mass of insulating-coated pure iron powder obtained by coating pure iron powder having an average particle size of 45 μm with a phosphate compound layer. A compact was obtained in the same manner as in Example 1, except that a compression molded body was obtained using this powder mixture.
(Example 3)
A green compact was obtained in the same manner as in Example 2, except that an insulating coated pure iron powder in which pure iron powder having an average particle size of 75 μm was coated with a phosphate compound layer was used.
(Example 4)
A powder mixture was obtained by adding 1.0 part by mass of barium stearate having an average particle size of 8 μm as an insulating component to 100 parts by mass of insulating-coated pure iron powder obtained by coating pure iron powder having an average particle size of 75 μm with a phosphate compound layer. A compact was obtained in the same manner as in Example 1, except that a compression molded body was obtained using this powder mixture.
(Example 5)
A powder mixture containing 100 parts by mass of insulating coated pure iron powder, which is made by coating pure iron powder with an average particle size of 160 μm with a phosphate compound layer, and 0.7 parts by mass of an amide-based lubricant with an average particle size of about 20 μm as an insulating component was prepared. A compact was obtained in the same manner as in Example 1, except that a compression molded body was obtained using this powder mixture.
（例６）
平均粒子径が６０μｍの純鉄粉末をリン酸化合物層で被覆した絶縁性被覆純鉄粉末１００質量部に対し、絶縁成分として平均粒子径が８μｍであるステアリン酸バリウム１．２質量部を添加し、粉末混合物を得た。この粉末混合物を用いて圧縮成形体を得た他は、例１と同様にして、圧粉体を得た。
（例７）
例４において、ステアリン酸バリウムの添加量を２．０質量部とした他は例４と同様にして、圧粉体を得た。
（例８）
例４において、ステアリン酸バリウムの添加量を２．３質量部とした他は例４と同様にして、圧粉体を得た。
上記処方を表１にまとめた。表１において、絶縁成分のＺｎはステアリン酸亜鉛であり、Ｂａはステアリン酸バリウムである。
(Example 6)
To 100 parts by mass of an insulating coated pure iron powder obtained by coating a pure iron powder having an average particle size of 60 μm with a phosphate compound layer, 1.2 parts by mass of barium stearate having an average particle size of 8 μm was added as an insulating component to obtain a powder mixture. A compact was obtained in the same manner as in Example 1, except that a compression molded body was obtained using this powder mixture.
(Example 7)
A green compact was obtained in the same manner as in Example 4, except that the amount of barium stearate added was changed to 2.0 parts by mass.
(Example 8)
A green compact was obtained in the same manner as in Example 4, except that the amount of barium stearate added was changed to 2.3 parts by mass.
The above formulation is summarized in Table 1. In Table 1, the insulating component Zn is zinc stearate, and Ba is barium stearate.
（評価）
さらに、励起磁束密度０．０１Ｔ、周波数２００ｋＨｚにおける複素透磁率（μ’）及び鉄損を測定した。結果を表１に示す。測定装置には、岩崎通信機株式会社製「Ｂ－Ｈアナライザ ＳＹ－８２５８」を用いた。
(evaluation)
Furthermore, the complex permeability (μ′) and iron loss were measured at an excitation magnetic flux density of 0.01 T and a frequency of 200 kHz. The results are shown in Table 1. The measurement device used was a “BH Analyzer SY-8258” manufactured by Iwasaki Electric Co., Ltd.
得られた圧粉磁心の断面をＶＨＸ－１０００顕微鏡（キーエンス製）を用いて倍率Ｚ１００Ｘ１０００＝１００００倍で観察し、サイズが１６００ｍｍ×１２００ｍｍの写真画像を得た。この写真画像から、純鉄の平均粒子径（μｍ）、数値Ａ（％）を求めた。
例１～例８の写真画像を図１及び図２に示す。
ここで、数値Ａ（％）は、純鉄粒子の外周部分において純鉄粒子の外周全長に対し幅０．４μｍ以上４．０μｍ以下である空隙部の割合である。
The cross section of the obtained dust core was observed at a magnification of Z100×1000=10,000 times using a VHX-1000 microscope (manufactured by Keyence Corporation) to obtain a photographic image measuring 1600 mm×1200 mm. From this photographic image, the average particle size (μm) of the pure iron and the value A (%) were obtained.
Photographic images of Examples 1 to 8 are shown in FIGS.
Here, the value A (%) is the ratio of voids having a width of 0.4 μm or more and 4.0 μm or less to the total periphery length of the pure iron particle in the outer periphery of the pure iron particle.
純鉄の平均粒子径は、上記で得られた写真画像において観察される３個の粒子について、長径及び短径を測定し、（長径＋短径）／２から粒子径を求め、３個の粒子径を平均して求めた。 The average particle size of pure iron was calculated by measuring the long and short diameters of three particles observed in the photographic image obtained above, calculating the particle size from (long diameter + short diameter)/2, and averaging the three particle sizes.
数値Ａは、以下の手順で測定した。
上記で得られた写真画像において全周長が撮影されている粒子をランダムで３個を選ぶ。各粒子と隣の粒子との間の空隙の幅を測定する。幅が０．４μｍ以上４．０μｍ以下であれば、その部分の空隙に対応する粒子の外周の長さを測定する。上記測定した長さを全周長で割った数値を数値Ａ（％）とする。３個の粒子の数値を平均化して数値Ａ（％）を求めた。
The value A was measured in the following manner.
Randomly select three particles whose total perimeter is captured in the photographic image obtained above. Measure the width of the gap between each particle and the adjacent particle. If the width is 0.4 μm or more and 4.0 μm or less, measure the outer perimeter of the particle corresponding to the gap in that portion. The value obtained by dividing the measured length by the total perimeter is taken as value A (%). Values for the three particles were averaged to obtain value A (%).
上記した結果から、純鉄の平均粒子径が６０～１５０μｍであり、数値Ａが５０％以上である例において、複素透磁率（μ’）が８０以上であり、鉄損が０．０２０（Ｗ／ｇ）以上であり、高複素透磁率かつ低鉄損となる結果が得られた。
各例の写真画像を図１及び図２に示す。これらの写真画像では、測定領域において粒子をランダムに選択し、この粒子の外周部分に観察される幅０．４μｍ以上４．０μｍ以下である空隙部を実線で示している。
例３、４、６の写真画像を示す図１（３）、（４）、図２（６）では、粒子が１個の粒子形状を維持した状態で、粒子の外周部に、幅０．４μｍ以上４．０μｍ以下である空隙部が５０％以上で観察された。
From the above results, in examples in which the average particle size of pure iron is 60 to 150 μm and the value A is 50% or more, the complex permeability (μ') is 80 or more and the iron loss is 0.020 (W/g) or more, resulting in high complex permeability and low iron loss.
Photographic images of each example are shown in Figures 1 and 2. In these photographic images, particles were randomly selected in the measurement area, and voids having a width of 0.4 μm to 4.0 μm observed in the outer periphery of the particles were indicated by solid lines.
In Fig. 1 (3), (4) and Fig. 2 (6) which show photographic images of Examples 3, 4 and 6, voids having a width of 0.4 µm or more and 4.0 µm or less were observed in 50% or more of the particles on the periphery while the particles maintained their individual particle shape.
例１では、潤滑剤粉末を添加していないため、粒子間の摩擦を起因とするヒステリシス損が発生して鉄損が増大した。また、鉄損が大きいため、複素透磁率が低下した。例１の写真画像を示す図１（１）では、隣り合う粒子の界面の空隙部が狭く、数値Ａが低下した。
例２では、純鉄の平均粒子径が４５μｍと小さいことから、渦電流損が減少して低鉄損となったが、小粒子径のため複素透磁率が低下した。例５では、純鉄の平均粒子径が１６０μｍと大きいことから、渦電流損が増加して鉄損が増大した。例５では、純鉄が粗大粒で、鉄損が大きいため、複素透磁率が低下した。例２、５の写真画像を示す図１（２）、図２（５）では、潤滑剤添加量が適量のため、数値Ａが５０％以上で観察された。
In Example 1, since no lubricant powder was added, hysteresis loss occurred due to friction between particles, and iron loss increased. In addition, complex permeability decreased due to the large iron loss. In FIG. 1(1) showing the photographic image of Example 1, the gap at the interface between adjacent particles was narrow, and the value A decreased.
In Example 2, the average particle size of the pure iron was small at 45 μm, so eddy current loss was reduced and the iron loss was low, but the complex permeability was reduced due to the small particle size. In Example 5, the average particle size of the pure iron was large at 160 μm, so eddy current loss increased and the iron loss increased. In Example 5, the complex permeability was reduced because the pure iron was coarse and the iron loss was large. In Figures 1 (2) and 2 (5), which show photographic images of Examples 2 and 5, the value A was observed to be 50% or more because the amount of lubricant added was appropriate.
例７では、純鉄の平均粒子径が小さいことから低鉄損であるが、絶縁成分の配合量が多く、粒子間の隙間部の幅が広いことから数値Ａが小さくなり、複素透磁率が低下した。例８では、例７よりも絶縁成分の配合量をさらに多くしており、複素透磁率がさらに低下した。例７、８の写真画像を示す図２（７）、（８）では、潤滑剤添加量が過大のため、隣り合う粒子の界面の空隙部が大きく、数値Ａが低下した。 In Example 7, the average particle size of the pure iron was small, resulting in low core loss, but the amount of insulating components was large and the gaps between the particles were wide, resulting in a small value A and a decrease in complex permeability. In Example 8, the amount of insulating components was even greater than in Example 7, resulting in a further decrease in complex permeability. In Figures 2 (7) and (8), which show photographs of Examples 7 and 8, the amount of lubricant added was excessive, resulting in large voids at the interfaces between adjacent particles and a decrease in value A.
一実施形態による圧粉磁心は、低鉄損かつ高複素透磁率が要求される用途に好ましく用いることができる。用途の一例としては、位置センサ等の電子機器用センサ、各種アクチュエータ等を挙げることができる。また、一実施形態による圧粉磁心は、１０ｋＨｚ～５００ｋＨｚの中周波数領域での使用に適している。 The powder magnetic core according to one embodiment can be preferably used in applications requiring low core loss and high complex permeability. Examples of applications include position sensors and other sensors for electronic devices, and various actuators. The powder magnetic core according to one embodiment is also suitable for use in the medium frequency range of 10 kHz to 500 kHz.
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