JPH0270003A - Method for treating ferromagnetic iron powder - Google Patents
Method for treating ferromagnetic iron powderInfo
- Publication number
- JPH0270003A JPH0270003A JP63162557A JP16255788A JPH0270003A JP H0270003 A JPH0270003 A JP H0270003A JP 63162557 A JP63162557 A JP 63162557A JP 16255788 A JP16255788 A JP 16255788A JP H0270003 A JPH0270003 A JP H0270003A
- Authority
- JP
- Japan
- Prior art keywords
- iron powder
- ferromagnetic iron
- phosphoric acid
- compound
- ferromagnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 230000005294 ferromagnetic effect Effects 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims description 13
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims abstract description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000001301 oxygen Substances 0.000 claims abstract description 16
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 16
- 239000012298 atmosphere Substances 0.000 claims abstract description 13
- 229910052751 metal Inorganic materials 0.000 claims abstract description 13
- 239000002184 metal Substances 0.000 claims abstract description 13
- 150000001875 compounds Chemical class 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 7
- -1 phosphoric acid compound Chemical class 0.000 claims abstract description 7
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 6
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 5
- 229910052802 copper Inorganic materials 0.000 claims abstract description 3
- 230000001590 oxidative effect Effects 0.000 claims abstract description 3
- 239000000725 suspension Substances 0.000 claims description 9
- 238000003672 processing method Methods 0.000 claims 1
- 230000005291 magnetic effect Effects 0.000 abstract description 20
- 150000003839 salts Chemical class 0.000 abstract description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052804 chromium Inorganic materials 0.000 abstract description 3
- 230000007797 corrosion Effects 0.000 abstract description 3
- 238000005260 corrosion Methods 0.000 abstract description 3
- 229910052759 nickel Inorganic materials 0.000 abstract description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 abstract description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 abstract description 2
- 229910002651 NO3 Inorganic materials 0.000 abstract description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 abstract description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 abstract description 2
- 239000003795 chemical substances by application Substances 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract 2
- CZZVVHBOSHSEGG-UHFFFAOYSA-N 1-hydroxyethane-1,2-disulfonic acid Chemical compound OS(=O)(=O)C(O)CS(O)(=O)=O CZZVVHBOSHSEGG-UHFFFAOYSA-N 0.000 abstract 1
- 239000003638 chemical reducing agent Substances 0.000 abstract 1
- 230000018044 dehydration Effects 0.000 abstract 1
- 238000006297 dehydration reaction Methods 0.000 abstract 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 19
- 230000005415 magnetization Effects 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 8
- 229910001873 dinitrogen Inorganic materials 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 7
- 239000011701 zinc Substances 0.000 description 7
- 239000011261 inert gas Substances 0.000 description 6
- 238000010301 surface-oxidation reaction Methods 0.000 description 6
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 5
- 239000006247 magnetic powder Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000004381 surface treatment Methods 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 3
- 229960001763 zinc sulfate Drugs 0.000 description 3
- 229910000368 zinc sulfate Inorganic materials 0.000 description 3
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000002736 metal compounds Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 150000003016 phosphoric acids Chemical class 0.000 description 2
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- 239000004254 Ammonium phosphate Substances 0.000 description 1
- HXYNGXRVDIIMTG-UHFFFAOYSA-N CCCO.OP(=O)OP(O)=O Chemical compound CCCO.OP(=O)OP(O)=O HXYNGXRVDIIMTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- DBVJJBKOTRCVKF-UHFFFAOYSA-N Etidronic acid Chemical compound OP(=O)(O)C(O)(C)P(O)(O)=O DBVJJBKOTRCVKF-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- URRHWTYOQNLUKY-UHFFFAOYSA-N [AlH3].[P] Chemical compound [AlH3].[P] URRHWTYOQNLUKY-UHFFFAOYSA-N 0.000 description 1
- JZQOJFLIJNRDHK-CMDGGOBGSA-N alpha-irone Chemical compound CC1CC=C(C)C(\C=C\C(C)=O)C1(C)C JZQOJFLIJNRDHK-CMDGGOBGSA-N 0.000 description 1
- FJMNNXLGOUYVHO-UHFFFAOYSA-N aluminum zinc Chemical compound [Al].[Zn] FJMNNXLGOUYVHO-UHFFFAOYSA-N 0.000 description 1
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 1
- 235000019289 ammonium phosphates Nutrition 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-M dihydrogenphosphate Chemical compound OP(O)([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-M 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 229960004585 etidronic acid Drugs 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000000052 vinegar Substances 0.000 description 1
- 235000021419 vinegar Nutrition 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000010887 waste solvent Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は磁気記録媒体用磁性粉として用いられる強磁性
鉄粉の表面処理方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for surface treatment of ferromagnetic iron powder used as magnetic powder for magnetic recording media.
（従来の技術）
塗布型磁気記録媒体は通常、磁性粉、バインダ研磨剤、
測滑剤および有機溶剤からなる磁性塗料をポリエステル
フィルムなどの基体に塗布したものである。(Prior art) Coated magnetic recording media usually contain magnetic powder, binder abrasive,
A magnetic coating consisting of a lubricant and an organic solvent is applied to a substrate such as a polyester film.
また強磁性鉄粉は、保磁力、飽和磁化か高いことから高
密度磁気記録媒体用の磁性粉として用途か広かりつつあ
り、更に高密度化の方向として磁性粉の微細化、高比表
面積が要求されている。In addition, ferromagnetic iron powder has high coercive force and saturation magnetization, so its use as magnetic powder for high-density magnetic recording media is expanding. requested.
しかし、強磁性鉄粉を微細、高比表面積とする場合、磁
性塗料調製時の鉄粉の分散性および記録媒体中での安定
性の点で問題が生じる。However, when the ferromagnetic iron powder is fine and has a high specific surface area, problems arise in terms of the dispersibility of the iron powder when preparing a magnetic coating material and its stability in a recording medium.
そこで、この問題点を解決するひとつの方法として、強
磁性鉄粉の表面処理が考えられるでおり、界面活性剤、
カップリング剤、高分子などを有機溶剤に溶解した溶液
中で強磁性鉄粉を処理する方法か知られている。しかし
ながら、有機溶剤を用いる方法は、作業性、廃溶剤の処
理なと、取り扱いが困難であり、コストも高くなる。Therefore, one way to solve this problem is to treat the surface of ferromagnetic iron powder.
A method is known in which ferromagnetic iron powder is treated in a solution containing a coupling agent, polymer, etc. dissolved in an organic solvent. However, methods using organic solvents are difficult to handle in terms of workability and disposal of waste solvents, and are also expensive.
一方、有機溶剤を用いず水溶液あるいは気相てｌＪ’！
：接処Ｐノ１する方法も多数開示されている。例えは、
特開昭５１．−４２９９０号公報には強磁性鉄粉とリン
酸・ｒオンを含む溶液とを接触させて処理する方θ、か
開示されている。しかしなからこの様な方法においても
安定化した磁性粉末の分散性、安定性は不十分であり、
特に強磁性鉄粉を乾燥した状態で取り扱う際に問題とな
る発火性の指標となる発火点の敗訴効果か小さい。On the other hand, lJ'! in aqueous solution or gas phase without using organic solvent!
:Many methods for contacting P-1 have also been disclosed. For example,
Japanese Patent Application Publication No. 1983. Japanese Patent No. 42990-42990 discloses a treatment method θ in which ferromagnetic iron powder is brought into contact with a solution containing phosphoric acid/r-ion. However, even with this method, the dispersibility and stability of the stabilized magnetic powder are insufficient.
In particular, the effect of the ignition point, which is an indicator of flammability, which is a problem when handling ferromagnetic iron powder in a dry state, is small.
（発明が解決しようとする課題）
本発明の［１的は、粉末の発火点か高く、磁性塗料中て
の分散性が良く、磁気記録媒体の配向性に優れた強磁性
鉄粉を得るための表面処理方法を提供することにある。(Problems to be Solved by the Invention) The first object of the present invention is to obtain ferromagnetic iron powder that has a high powder ignition point, good dispersibility in magnetic paint, and excellent orientation for magnetic recording media. The object of the present invention is to provide a surface treatment method.
（課題を解決するための手段）
本発明者らは上記問題点を解決するために鋭意検討を行
った結果、表面酸化した後の強磁性鉄粉表面にリン酸と
金属の化合物を付右さゼることにより、分散性および安
定性に優れた強磁性鉄粉がｔｌｌられることを見出し、
本発明を完成するに至った。ずなわぢ本発明は、乾式還
元法で製造１〜だ鉄を主成分とする強磁性鉄粉を、酸素
を含む雰囲気中で表面酸化した後、水に懸濁し、得られ
た懸濁液にリン酸化合物とＺｎ、 Ｇｏ、旧、 Ｃｒ、
Ｃｕ、 ＦｅおよびＡｌからなる群から選ばれた１挿
置」二の金属の塩を添加し、強磁性鉄粉にリン酸と金属
の化合物をイ・Ｉ”ｉＥｆさけることを特徴とする強磁
性鉄粉の処理方法である。以下、その詳細について説明
する。(Means for Solving the Problems) The present inventors conducted intensive studies to solve the above problems, and found that a compound of phosphoric acid and metal was attached to the surface of ferromagnetic iron powder after surface oxidation. discovered that ferromagnetic iron powder with excellent dispersibility and stability could be produced by
The present invention has now been completed. Zunawaji The present invention is manufactured using a dry reduction method. After oxidizing the surface of ferromagnetic iron powder mainly composed of iron in an oxygen-containing atmosphere, it is suspended in water, and the resulting suspension is Phosphoric acid compounds and Zn, Go, old, Cr,
Ferromagnetic iron powder characterized by adding a salt of one metal selected from the group consisting of Cu, Fe and Al, and avoiding a compound of phosphoric acid and metal to the ferromagnetic iron powder. This is a method for processing iron powder.The details will be explained below.
通常、強磁性鉄粉は平均長さ１μｍ以下、針状比３以上
の微粒子の集合物であり、粉末、造粒物。Usually, ferromagnetic iron powder is an aggregate of fine particles with an average length of 1 μm or less and an acicular ratio of 3 or more, and is a powder or granulated product.
破砕物なと種々の形状を有している。この強磁性鉄粉は
鉄を主成分とするものであるが、その他の成分として、
コバルト、ニッケル、クロム、リンアルミニウム、チタ
ン、シリコン、ジルコニウム。Crushed materials come in a variety of shapes. This ferromagnetic iron powder has iron as its main component, but other components include:
Cobalt, nickel, chromium, phosphorus aluminum, titanium, silicon, zirconium.
カルシウム、マグネシウム、亜鉛などを適宜添加し７た
ものも用いることか−Ｃきる。Calcium, magnesium, zinc, etc. may be added as appropriate and used.
また、この強磁性Ｖ、粉は含水酸化鉄、酸化鉄なとを乾
式還元することによって１！７ることかできるが、特に
α−オキシ水酸化鉄の表向を焼結防止剤′３
などで処理したのち、脱水・焼成し、酸化第二Ｖ、とし
、次いで水素ガスを用い乾式還元して得たものを用いる
ことか好ましい。In addition, this ferromagnetic V powder can be made by dry reduction of hydrated iron oxide, iron oxide, etc., but in particular, the surface of α-iron oxyhydroxide can be treated with an anti-sintering agent. It is preferable to use a product obtained by treating with water, dehydrating and calcining to obtain a second V oxide, and then dry reducing it using hydrogen gas.
更にこの還元直後の強磁性鉄粉は、空気中に取り出すと
発火するおそれかあるので不活性ガス雰囲気ドで取り扱
うことか好ましい。Furthermore, since the ferromagnetic iron powder immediately after reduction may catch fire if taken out into the air, it is preferable to handle it in an inert gas atmosphere.
次に寄られた強磁性鉄粉を酸素を含む雰囲気中で表面酸
化し、耐蝕性、 １ｆｌｉ、Ｉ磁性をイｉＩ”Ｕする。Next, the surface of the collected ferromagnetic iron powder is oxidized in an oxygen-containing atmosphere to improve its corrosion resistance, I, and magnetism.
この気相中での表面酸化としては従来法か採用できるが
、温度２００℃以下、酸素濃度０．０５容量％以上人気
絹成以下、水蒸気濃度５０００ ｐｐｍ以下の不活性ガ
ス雰囲気中で、強磁性鉄粉１．０ｋｇあたり０２として
５０〜１５０ｇの酸化量の酸化を杓うことか好ましい。Conventional methods can be used for surface oxidation in the gas phase, but ferromagnetic It is preferable to oxidize in an amount of 50 to 150 g as 0.02 per 1.0 kg of iron powder.
また、このとき温度を４段階に変化させて酸化反応を行
えばより優れた耐蝕性、耐候性をイζＩ”ｊ、すること
ができるので更に好まし２い。温度を４段階に々化させ
て反応を行う場合、１段］二１の反応は５０〜１５０℃
、２段「１の反応は０〜４０°Ｃ，３段「１の反応は４
５〜７０°Ｃ史に４段「Ｊの反応は０〜４０℃の温度下
で行い、雰囲気中の酸素濃度は１段Ｌ１から３段目の反
応においては（’、） 、 ０５容量％以」二大気組
成以下、４段目の反応においては］、０容量％以」二大
気組成以下とし、このときの１段ｌソｔの反応における
酸化量は強磁性鉄粉］、Ｏｋｇあたり として５０〜１
００ ｇとし、２段１Ｉの反応は酸化が停止トするか一
定の酸化速度となったところで反応を終了しく通常２〜
８時間）３段［ｊの反応における酸化量はコ段１」の反
応の５〜３０％量とし、更に強磁性鉄粉の発火性を抑制
するために行う４段に１の反応は１〜５時間としてｉう
うことか好ましい。Further, it is more preferable to carry out the oxidation reaction while changing the temperature in four steps, since better corrosion resistance and weather resistance can be achieved. When the reaction is carried out at 50 to 150°C, the reaction in step 1]
, 2nd stage "1 reaction is 0-40°C, 3rd stage "1 reaction is 4
5 to 70 °C, the reaction in 4 stages is carried out at a temperature of 0 to 40 °C, and the oxygen concentration in the atmosphere is (',) 05% by volume or less in the reactions from the first stage L1 to the third stage. The oxidation amount in the 1st stage reaction is 50% per kg of ferromagnetic iron powder. ~1
00 g, and the reaction in the second stage 1I ends when the oxidation stops or reaches a certain oxidation rate.
8 hours) The amount of oxidation in the 3rd stage [j reaction is 5 to 30% of the reaction in stage 1], and the oxidation amount in the 4th stage reaction to further suppress the ignitability of the ferromagnetic iron powder is 1 to 30%. It is preferable to use it for 5 hours.
このように温度を特定化し、順次変化させて酸化物を形
成させることで耐候性に優れ、高飽和磁化の強磁性鉄粉
を得ることかできる。By specifying and sequentially changing the temperature in this way to form oxides, it is possible to obtain ferromagnetic iron powder with excellent weather resistance and high saturation magnetization.
また、表面酸化に用いる酸素ガスを含む雰囲気としては
、酸素と不活性ガスの混合雰囲気、大気を不活性カスで
希釈した雰囲気なとを挙げることかでき、表面酸化で用
いる装置としては固定床方式、流動床方式１回転型キル
ン方式など種々のものか採用できる。In addition, examples of the atmosphere containing oxygen gas used for surface oxidation include a mixed atmosphere of oxygen and inert gas, and an atmosphere in which the atmosphere is diluted with inert gas. , a fluidized bed system, a single rotation kiln system, and various other methods can be adopted.
表面酸化後の強磁性鉄粉は水に懸濁し、？１１られた懸
濁液にリン酸化合物と金属塩を加えることにより強磁性
鉄粉表面にリン酸と金属の化合物を付合させ表面処理を
行なうが、懸濁液を得る際に、予め表面酸化後の強磁性
鉄粉を水蒸気を含む雰囲気中で処理しておけば、懸濁時
に生ずる強磁性鉄粉の発熱を抑制することができ、これ
により強磁性鉄粉の磁性劣化を防ぐことができるので好
ましい。Ferromagnetic iron powder after surface oxidation is suspended in water? By adding a phosphoric acid compound and a metal salt to the suspension, the ferromagnetic iron powder surface is treated with a phosphoric acid and metal compound. If the ferromagnetic iron powder is subsequently treated in an atmosphere containing water vapor, it is possible to suppress the heat generation of the ferromagnetic iron powder that occurs during suspension, thereby preventing magnetic deterioration of the ferromagnetic iron powder. Therefore, it is preferable.
懸濁液に添加するリン酸化合物としては、ヒドロキシエ
タンジホスホン酸、、ヒドロキシプロパンジホスホン酸
、ヒドロキシブタンジホスホン酸リン酸、リン酸すトリ
ウム、リン酸二水素すトリウム、リン酸アンモニウムな
どが挙げられ、一方金属塩としては、Ｚｎ、 Ｇｏ、
Ｎｉ、 Ｃｒ、 Ｃｕ、 ＰｃおよびＡｌからなる群か
ら選ばれた１種以上の金属の硫酸塩、塩酸塩、硝酸塩、
酢酸塩などが挙げられる。Examples of phosphoric acid compounds to be added to the suspension include hydroxyethane diphosphonic acid, hydroxypropane diphosphonic acid, hydroxybutane diphosphonic acid phosphoric acid, sterium phosphate, sterium dihydrogen phosphate, and ammonium phosphate. On the other hand, the metal salts include Zn, Go,
sulfate, hydrochloride, nitrate of one or more metals selected from the group consisting of Ni, Cr, Cu, Pc and Al;
Examples include acetate.
これらは各々、単独であるいは２種以上を混合して用い
ることかできる。またその添加量は各々懸濁した鉄粉に
対して、リン酸化合物は０．１〜２０重量％、金属塩は
０．１〜２０重間％であることが好ましく、これより添
加量が多い場合、鉄粉の表面を均一に処理することが困
難となるおそれかあり、少ない場合、充分な表面処理効
果が得られないことがある。Each of these can be used alone or in combination of two or more. In addition, the amounts added are preferably 0.1 to 20% by weight for the phosphoric acid compound and 0.1 to 20% by weight for the metal salt, with the amount added being larger than these. If there is a small amount, it may be difficult to uniformly treat the surface of the iron powder, and if there is a small amount, a sufficient surface treatment effect may not be obtained.
また、上記リン酸化合物および金属塩を添加する際に懸
濁液は温度Ｏ〜８０°Ｃ，ｐＨ４，０〜１０．０とする
ことか好ましく、温度が８０°Ｃを越える場合またはｐ
Ｈが上記範囲外の場合は強磁性鉄粉の磁気特性、安定性
が低下するおそれかある。In addition, when adding the above-mentioned phosphoric acid compound and metal salt, it is preferable that the suspension has a temperature of 0 to 80°C and a pH of 4.0 to 10.0; if the temperature exceeds 80°C or
If H is outside the above range, the magnetic properties and stability of the ferromagnetic iron powder may deteriorate.
更に、リン酸と金属の化合物の付着量は強磁性鉄粉に対
し、０．１〜５重量％とすることが好ましく、この（＝
１着量はリン酸化合物と金属塩の添加量あるいは添加時
の！Ｖ濁液のｐＨ，温度などを変えることにより適宜調
整することができる。付着量が０．１重量％に満だない
場合は、処理効果が現われないおそれがあり、５重量％
を越えると強磁性ｖく粉の飽和磁化か小さくなる傾向が
ある。Further, the amount of the phosphoric acid and metal compound attached is preferably 0.1 to 5% by weight based on the ferromagnetic iron powder, and this (=
The amount per coat is the amount or time of addition of phosphoric acid compound and metal salt! It can be adjusted as appropriate by changing the pH, temperature, etc. of the V suspension. If the amount of adhesion is less than 0.1% by weight, there is a risk that the treatment effect will not appear, and 5% by weight.
If the value exceeds 1, the saturation magnetization of the ferromagnetic powder tends to decrease.
表面処理後の強磁性鉄粉は、濾過、洗浄後乾燥を行なう
が、このときの乾燥は不活性ガス又は酸素濃度２容量％
以下の不活性ガス雰囲気下で行ない、乾燥後酸素濃度を
次第に大気組成まで上げてゆくことにより、耐候性に優
れた強磁性鉄粉か得られるので好ましい。The ferromagnetic iron powder after surface treatment is filtered, washed, and then dried.Drying at this time is done using an inert gas or an oxygen concentration of 2% by volume.
It is preferable to carry out the drying process in the following inert gas atmosphere and gradually increase the oxygen concentration to atmospheric composition after drying, since this yields ferromagnetic iron powder with excellent weather resistance.
（実施例）
以下、実施例により本発明を、更に詳細に説明するが本
発明は何らこれらに限定されるものではない。(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these in any way.
実施例１
針状酸化第２鉄を水素気流中で還元して得た強磁性鉄粉
を窒素ガス気流中で９０℃まで冷却した後、表面酸化を
行った。また、表面酸化は温度を４段階に変化させて流
動反応炉内で行った。Example 1 Ferromagnetic iron powder obtained by reducing acicular ferric oxide in a hydrogen stream was cooled to 90°C in a nitrogen gas stream, and then surface oxidized. Moreover, the surface oxidation was performed in a fluidized reactor while changing the temperature in four stages.
１段目の反応は、酸素０．２容量％含む窒素ガスを反応
炉内に供給し強磁性鉄粉１．０ｋｇあたり酸化量が０２
として７ＣＪｇとなったところで止めた。次いで、窒素
ガス気流中で２０℃まで冷却した後酸素０，２容量％含
む窒素ガスを供給し、酸素消費量がほぼ一定となるまで
２段目の反応を行った。In the first stage reaction, nitrogen gas containing 0.2% by volume of oxygen was supplied into the reactor, and the amount of oxidation was 0.2% per 1.0kg of ferromagnetic iron powder.
I stopped when it reached 7CJg. Next, after cooling to 20° C. in a nitrogen gas stream, nitrogen gas containing 0.2% by volume of oxygen was supplied, and the second stage reaction was carried out until the amount of oxygen consumption became almost constant.
２段１」の反応終了後、引続き酸素０．２容量％含む窒
素ガスを反応炉内に供給しながら温度を２０°Ｃ／時の
割合で５０°Ｃまて上げ、３段目の反応を行った。この
時の酸化量は強磁性鉄粉１．、Ｏｋｇあたり１− Ｏｇ
とした。After the completion of the second stage 1 reaction, the temperature was increased to 50°C at a rate of 20°C/hour while continuing to supply nitrogen gas containing 0.2% oxygen by volume into the reactor, and the third stage reaction was started. went. The amount of oxidation at this time is 1. , 1-Og per Okg
And so.
３段目の反応終了後、酸素の供給を停止し窒素気流中で
２０°Ｃまて冷却し、再び酸素０．２容量％含む窒素ガ
スの供給を行い４段目の反応を行った。After the third stage reaction was completed, the supply of oxygen was stopped, the mixture was cooled to 20°C in a nitrogen stream, and nitrogen gas containing 0.2% by volume of oxygen was supplied again to carry out the fourth stage reaction.
４段１］の反応において酸素を含む窒素ガス中の酸素濃
度を次第に上げてゆき、１時間後に酸素濃度を２容量％
とじ、更にそのまま１時間反応を続けた後、終了した。In the reaction of Step 4 1], the oxygen concentration in the nitrogen gas containing oxygen is gradually increased, and after 1 hour, the oxygen concentration is increased to 2% by volume.
After closing, the reaction was continued for 1 hour and then terminated.
表面酸化後の強磁性鉄粉を不活性ガス雰囲気下で水に１
ＰＪｉ４５して得られた懸濁液に、苛性ソーダでｐＨ７
に調整した１−ヒドロキシ−１，１−ジホスホン酸水溶
液と硫酸亜鉛水溶液の混合水溶液を］ ０
撹拌しながら添加し、その後懸濁液を２０°Ｃて］時間
放置した。Ferromagnetic iron powder after surface oxidation is dissolved in water under an inert gas atmosphere.
The suspension obtained by PJi45 was adjusted to pH 7 with caustic soda.
A mixed aqueous solution of a 1-hydroxy-1,1-diphosphonic acid aqueous solution and a zinc sulfate aqueous solution adjusted to 0 was added with stirring, and the suspension was then left at 20°C for an hour.
濾過水洗後、４０℃で真空乾燥した強磁性鉄粉には、リ
ン酸とＺｎの化合物が強磁性鉄粉に対しＺｎとして１．
５重塁％含有されていた。After filtering and washing with water, the ferromagnetic iron powder was vacuum-dried at 40°C, and a compound of phosphoric acid and Zn was added to the ferromagnetic iron powder in a ratio of 1.
It contained 5% double bases.
得られた強磁性鉄粉の磁気特性は振動試料型磁力計（７
１＋１１定磁場１０ＫＯｅ）を用いて１（ＩＩＩ定し、
耐候性は温度６０℃、相対湿度９０％の条件で１週間放
置後の飽和磁化（ａｓ）を７１１１１定して求めた。The magnetic properties of the obtained ferromagnetic iron powder were measured using a vibrating sample magnetometer (7
1(III) using 1+11 constant magnetic field 10KOe),
Weather resistance was determined by determining the saturation magnetization (as) of 71111 after being left for one week at a temperature of 60° C. and a relative humidity of 90%.
また、発火点は示唆熱分析装置（’ＤＴＡ）を用い、空
気中、昇温速度１０℃／分で１ｌｌ１１定した。Further, the ignition point was determined at 11111 using a suggestive thermal analyzer ('DTA) in air at a heating rate of 10° C./min.
更に、得られた磁性粉末１００重量部、塩ビ酢ピコポリ
マー２５重量部、レシチン１．５重量部、メチルエチル
ケトン１６０ｍ１． シクロへキサノン１６０ ｍｌ
をガラスピーズを入れたサンドグラインダーで６時間混
合２分散して磁性塗料を調製し、これより配向シートを
作製し、得られた配向シーｉ・の角形比（Ｒｓ）を振動
試料型磁力計を用いて測定した。Furthermore, 100 parts by weight of the obtained magnetic powder, 25 parts by weight of vinyl chloride vinegar picopolymer, 1.5 parts by weight of lecithin, and 160 ml of methyl ethyl ketone were added. Cyclohexanone 160 ml
A magnetic paint was prepared by mixing and dispersing for 6 hours with a sand grinder containing glass beads, from which an oriented sheet was made, and the squareness ratio (Rs) of the obtained oriented sheet i was measured using a vibrating sample magnetometer. It was measured using
その結果、強磁性鉄粉の保磁力は１４８５’Ｏｅ飽和磁
化は１３３ｅｍｕ／ｇ、比表面積５３イ／ｇ発火点は］
３６℃であった。As a result, the coercive force of the ferromagnetic iron powder was 1485'Oe, the saturation magnetization was 133 emu/g, and the specific surface area was 53 I/g, and the ignition point was]
The temperature was 36°C.
また、耐候性はａｓ −１１８ｅｍｕ ／ｇと良好であ
り、配向シートはＲｓ ０１８４と配向性に優れたも
のであった。Furthermore, the weather resistance was as-118 emu/g, which was good, and the oriented sheet had an excellent orientation of Rs 0184.
実施例２
表面処理をヘキサメタリン酸ソーダ、塩化アルミニウム
を用いて行った以外は実施例１と同様の方法で、リン酸
とアルミニウムの化合物を付着させた強磁性鉄粉を得た
。Example 2 Ferromagnetic iron powder to which a compound of phosphoric acid and aluminum was attached was obtained in the same manner as in Example 1, except that the surface treatment was performed using sodium hexametaphosphate and aluminum chloride.
１１、ｉられた強磁性鉄粉にはリン酸とアルミニウムの
化合物が八Ωとして１．２重量％含有されており、磁気
特性は保磁力１４８００ｅ、飽和磁化１３４ｅｍｕ／ｇ
で、比表面積５３ｒｄ／ｇ、発火点は１３８℃であった
。11. The prepared ferromagnetic iron powder contains 1.2% by weight of a compound of phosphoric acid and aluminum as 8Ω, and has magnetic properties such as a coercive force of 14,800e and a saturation magnetization of 134emu/g.
The specific surface area was 53rd/g and the ignition point was 138°C.
また、耐候性はａｓ ＝ １２０ｅｍｕ ／ｇ、配向シ
トのＲｓは０．８５であった。Further, the weather resistance was as=120 emu/g, and the Rs of the oriented sheet was 0.85.
］ ］
実施例３
表面処理をヘキサメタリン酸ソーダと塩化アルミニウム
、硫酸亜鉛を用いて行った以外は実施例］と同様の方法
でリン酸とアルミニウム、亜鉛の化合物を（１着させた
強磁性鉄粉を得た。] ] Example 3 A compound of phosphoric acid, aluminum, and zinc was coated with ferromagnetic iron powder (coated with I got it.
得られた強磁性鉄粉にはリン酸とアルミニウム亜鉛の化
合物がΔｇとして１．０重量％ Ｚｎとして１．２重量
％含有されていたおり、磁気特性は保磁力１．４８００
ｅ 、飽和磁化１３２ｅｍｕ／ｇで、比表面積５３ｎ
ｆ／ｇ、発火点は１４３℃であった。The obtained ferromagnetic iron powder contained a compound of phosphoric acid and aluminum zinc at 1.0% by weight as Δg and 1.2% by weight as Zn, and its magnetic properties were as follows: coercive force 1.4800
e, saturation magnetization 132 emu/g, specific surface area 53 n
f/g, and the ignition point was 143°C.
また、耐候性はａｓ −１２２ｅｍｕ ／ ｇ、配向シ
ートはＲｓｏ、８６であった。Further, the weather resistance was as -122emu/g, and the orientation sheet Rso was 86.
比較例１
リン酸と亜鉛の化合物を（＝１着させる処理を行わなか
った以外は、実施例１と同様の方法で強磁性鉄粉を製造
した。Comparative Example 1 Ferromagnetic iron powder was produced in the same manner as in Example 1, except that the treatment of depositing a compound of phosphoric acid and zinc (=1) was not performed.
得られた強磁性鉄粉の磁気特性は、保磁力１４９００ｅ
、飽和磁化］、３５ｅｍｕ／ｇで、比表面積５４ ｎｆ
／ ｇであり、発火点は１１０℃であった。The magnetic properties of the obtained ferromagnetic iron powder have a coercive force of 14900e
, saturation magnetization], 35 emu/g, specific surface area 54 nf
/g, and the ignition point was 110°C.
また、耐候性はａｓ −１１，２ｅｍｕ ／ ｇ＋配向
シトはＲｓ ０４８０であった。Moreover, the weather resistance was Rs 0480 for the as-11,2emu/g+ oriented sheet.
比較例２
硫酸亜鉛水溶液を用いずに１−ヒドロキシ−１゜１−ジ
ホスホン酸水溶液のみで処理した以外は実施例］と同様
の方法で強磁性鉄粉を製造した。Comparative Example 2 Ferromagnetic iron powder was produced in the same manner as in Example except that the treatment was performed only with an aqueous 1-hydroxy-1°1-diphosphonic acid solution without using an aqueous zinc sulfate solution.
得られた強磁性鉄粉の磁気特性は、保磁力１、４８００
ｅ 、飽和磁化１３２ｅｍｕ／ｇで、比表面積５３ｒ
ｒ？／ｇであり、発火点は１１３°Ｃであった。The magnetic properties of the obtained ferromagnetic iron powder are as follows: coercive force 1,4800
e, saturation magnetization 132 emu/g, specific surface area 53 r
r? /g, and the ignition point was 113°C.
また、耐候性はａｓ −１１５ｅｍｕ ／ｇ、配向シト
はＲｓｏ、８１であった。Moreover, the weather resistance was as -115 emu/g, and the orientation site Rso was 81.
比較例３
実施例１において、］−］ヒドロキシー１，１ジホスホ
ンを用いず、硫酸亜鉛水溶液のみで処理した以外は実施
例１と同様にして強磁性鉄粉を製造した。Comparative Example 3 Ferromagnetic iron powder was produced in the same manner as in Example 1, except that the treatment was performed only with an aqueous zinc sulfate solution without using ]-]hydroxy-1,1 diphosphone.
］ ４
得られた強磁性鉄粉の磁気特性は、保磁力１．４８００
ｅ 、飽和磁化］、３０ｅｍｕ／ｇで、比表面積５３
ｒｒｒ ／ ｇであり、発火点は１１０°Ｃであった
。] 4 The magnetic properties of the obtained ferromagnetic iron powder are as follows: coercive force 1.4800
e, saturation magnetization], 30 emu/g, specific surface area 53
rrr/g, and the ignition point was 110 °C.
また、耐候性はσｓ −１１０ｃｍｕ ／ｇ、配向ント
はＲｓＯ，７８であった。Further, the weather resistance was σs -110 cmu/g, and the orientation was RsO, 78.
（発明の効果）
以上述べたとおり、本発明の処理方法を施した強磁性鉄
粉は発火点か高いものとなり、その取扱いは容品なもの
となる。また、得られる強磁性鉄粉は分散性が良好であ
り、これより得られる磁気記録媒体は配向性、安定性な
どの点で優れたものとなる。(Effects of the Invention) As described above, the ferromagnetic iron powder subjected to the treatment method of the present invention has a high ignition point and must be handled with care. Furthermore, the obtained ferromagnetic iron powder has good dispersibility, and the magnetic recording medium obtained therefrom is excellent in terms of orientation, stability, etc.
Claims (1)
粉を、酸素を含む雰囲気中で表面酸化した後、水に懸濁
し、得られた懸濁液にリン酸化合物とＺｎ，Ｃｏ，Ｎｉ
，Ｃｒ，Ｃｕ，ＦｅおよびＡｌからなる群から選ばれた
１種以上の金属の塩を添加し、強磁性鉄粉にリン酸と金
属の化合物を付着させることを特徴とする強磁性鉄粉の
処理方法。(1) After oxidizing the surface of ferromagnetic iron powder whose main component is iron produced by a dry reduction method in an oxygen-containing atmosphere, it is suspended in water, and the resulting suspension contains a phosphoric acid compound, Zn, Co,Ni
, Cr, Cu, Fe, and Al, and a compound of phosphoric acid and metal is attached to the ferromagnetic iron powder. Processing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63162557A JPH0270003A (en) | 1988-07-01 | 1988-07-01 | Method for treating ferromagnetic iron powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63162557A JPH0270003A (en) | 1988-07-01 | 1988-07-01 | Method for treating ferromagnetic iron powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0270003A true JPH0270003A (en) | 1990-03-08 |
Family
ID=15756853
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63162557A Pending JPH0270003A (en) | 1988-07-01 | 1988-07-01 | Method for treating ferromagnetic iron powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0270003A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0421702A (en) * | 1990-05-16 | 1992-01-24 | Michitoshi Hirata | Metal fine powder and manufacture thereof |
| US5484545A (en) * | 1992-11-11 | 1996-01-16 | Toda Kogyo Corporation | Magnetic particles for magnetic recording medium and process for producing the same |
| WO1997047416A1 (en) * | 1996-06-10 | 1997-12-18 | Nittetsu Mining Co., Ltd. | Powder coated with multilayer coating |
| KR100618122B1 (en) * | 2005-06-01 | 2006-08-30 | 한국과학기술연구원 | Surface oxidation of fe based amorphous metal by wet process |
| WO2012173239A1 (en) * | 2011-06-17 | 2012-12-20 | 株式会社神戸製鋼所 | Iron-base soft magnetic powder for dust cores, manufacturing method thereof, and dust core |
| US20140047932A1 (en) * | 2011-02-25 | 2014-02-20 | Global Scientific Services Pty Ltd | Method, system and apparatus for use in locating subsurface ore bodies |
-
1988
- 1988-07-01 JP JP63162557A patent/JPH0270003A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0421702A (en) * | 1990-05-16 | 1992-01-24 | Michitoshi Hirata | Metal fine powder and manufacture thereof |
| US5484545A (en) * | 1992-11-11 | 1996-01-16 | Toda Kogyo Corporation | Magnetic particles for magnetic recording medium and process for producing the same |
| US5543069A (en) * | 1992-11-11 | 1996-08-06 | Toda Kogyo Corporation | Magnetic particles for magnetic recording medium and process for producing the same |
| WO1997047416A1 (en) * | 1996-06-10 | 1997-12-18 | Nittetsu Mining Co., Ltd. | Powder coated with multilayer coating |
| EA000820B1 (en) * | 1996-06-10 | 2000-04-24 | Ниттецу Майнинг Ко., Лтд. | Powder coated with multilayer coating |
| KR100618122B1 (en) * | 2005-06-01 | 2006-08-30 | 한국과학기술연구원 | Surface oxidation of fe based amorphous metal by wet process |
| US20140047932A1 (en) * | 2011-02-25 | 2014-02-20 | Global Scientific Services Pty Ltd | Method, system and apparatus for use in locating subsurface ore bodies |
| US9823170B2 (en) * | 2011-02-25 | 2017-11-21 | Global Scientific Services Pty Ltd | Method, system and apparatus for use in locating subsurface ore bodies |
| WO2012173239A1 (en) * | 2011-06-17 | 2012-12-20 | 株式会社神戸製鋼所 | Iron-base soft magnetic powder for dust cores, manufacturing method thereof, and dust core |
| JP5189691B1 (en) * | 2011-06-17 | 2013-04-24 | 株式会社神戸製鋼所 | Iron-based soft magnetic powder for dust core, method for producing the same, and dust core |
| US9472328B2 (en) | 2011-06-17 | 2016-10-18 | Kobe Steel, Ltd. | Iron-based soft magnetic powder for dust core use, manufacturing method thereof, and dust core |
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