JPH0148323B2 - - Google Patents
Info
- Publication number
- JPH0148323B2 JPH0148323B2 JP59175151A JP17515184A JPH0148323B2 JP H0148323 B2 JPH0148323 B2 JP H0148323B2 JP 59175151 A JP59175151 A JP 59175151A JP 17515184 A JP17515184 A JP 17515184A JP H0148323 B2 JPH0148323 B2 JP H0148323B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic powder
- metal magnetic
- mercaptan
- surface treatment
- powder
- 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.)
- Expired
Links
- 239000002184 metal Substances 0.000 claims description 68
- 229910052751 metal Inorganic materials 0.000 claims description 68
- 239000006247 magnetic powder Substances 0.000 claims description 66
- 238000000034 method Methods 0.000 claims description 20
- 238000004381 surface treatment Methods 0.000 claims description 20
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 12
- CUPCBVUMRUSXIU-UHFFFAOYSA-N [Fe].OOO Chemical compound [Fe].OOO CUPCBVUMRUSXIU-UHFFFAOYSA-N 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 229910021519 iron(III) oxide-hydroxide Inorganic materials 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- 239000011261 inert gas Substances 0.000 claims description 9
- GUUVPOWQJOLRAS-UHFFFAOYSA-N Diphenyl disulfide Chemical compound C=1C=CC=CC=1SSC1=CC=CC=C1 GUUVPOWQJOLRAS-UHFFFAOYSA-N 0.000 claims description 8
- -1 mercaptan compound Chemical class 0.000 claims description 6
- 125000004432 carbon atom Chemical group C* 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 3
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 claims description 2
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 claims description 2
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims 1
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 27
- 150000002898 organic sulfur compounds Chemical class 0.000 description 20
- 230000003647 oxidation Effects 0.000 description 16
- 238000007254 oxidation reaction Methods 0.000 description 16
- 239000000843 powder Substances 0.000 description 13
- 238000000137 annealing Methods 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 239000003960 organic solvent Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 230000005415 magnetization Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000003973 paint Substances 0.000 description 4
- RMVRSNDYEFQCLF-UHFFFAOYSA-N thiophenol Chemical compound SC1=CC=CC=C1 RMVRSNDYEFQCLF-UHFFFAOYSA-N 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- ULIKDJVNUXNQHS-UHFFFAOYSA-N 2-Propene-1-thiol Chemical compound SCC=C ULIKDJVNUXNQHS-UHFFFAOYSA-N 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- LSDPWZHWYPCBBB-UHFFFAOYSA-N Methanethiol Chemical class SC LSDPWZHWYPCBBB-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- PMBXCGGQNSVESQ-UHFFFAOYSA-N 1-Hexanethiol Chemical compound CCCCCCS PMBXCGGQNSVESQ-UHFFFAOYSA-N 0.000 description 2
- ZRKMQKLGEQPLNS-UHFFFAOYSA-N 1-Pentanethiol Chemical compound CCCCCS ZRKMQKLGEQPLNS-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 238000007605 air drying Methods 0.000 description 2
- WQAQPCDUOCURKW-UHFFFAOYSA-N butanethiol Chemical compound CCCCS WQAQPCDUOCURKW-UHFFFAOYSA-N 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 229920002545 silicone oil Polymers 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- 239000008096 xylene Substances 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 description 1
- LXUNZSDDXMPKLP-UHFFFAOYSA-N 2-Methylbenzenethiol Chemical compound CC1=CC=CC=C1S LXUNZSDDXMPKLP-UHFFFAOYSA-N 0.000 description 1
- ZJCZFAAXZODMQT-UHFFFAOYSA-N 2-methylpentadecane-2-thiol Chemical compound CCCCCCCCCCCCCC(C)(C)S ZJCZFAAXZODMQT-UHFFFAOYSA-N 0.000 description 1
- VZXOZSQDJJNBRC-UHFFFAOYSA-N 4-chlorobenzenethiol Chemical compound SC1=CC=C(Cl)C=C1 VZXOZSQDJJNBRC-UHFFFAOYSA-N 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- VPIAKHNXCOTPAY-UHFFFAOYSA-N Heptane-1-thiol Chemical compound CCCCCCCS VPIAKHNXCOTPAY-UHFFFAOYSA-N 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- UIJGNTRUPZPVNG-UHFFFAOYSA-N benzenecarbothioic s-acid Chemical compound SC(=O)C1=CC=CC=C1 UIJGNTRUPZPVNG-UHFFFAOYSA-N 0.000 description 1
- UENWRTRMUIOCKN-UHFFFAOYSA-N benzyl thiol Chemical compound SCC1=CC=CC=C1 UENWRTRMUIOCKN-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- CMKBCTPCXZNQKX-UHFFFAOYSA-N cyclohexanethiol Chemical compound SC1CCCCC1 CMKBCTPCXZNQKX-UHFFFAOYSA-N 0.000 description 1
- VTXVGVNLYGSIAR-UHFFFAOYSA-N decane-1-thiol Chemical compound CCCCCCCCCCS VTXVGVNLYGSIAR-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- WNAHIZMDSQCWRP-UHFFFAOYSA-N dodecane-1-thiol Chemical compound CCCCCCCCCCCCS WNAHIZMDSQCWRP-UHFFFAOYSA-N 0.000 description 1
- 235000019441 ethanol Nutrition 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- YNESSCJHABBEIO-UHFFFAOYSA-N nonadecane-1-thiol Chemical compound CCCCCCCCCCCCCCCCCCCS YNESSCJHABBEIO-UHFFFAOYSA-N 0.000 description 1
- ZVEZMVFBMOOHAT-UHFFFAOYSA-N nonane-1-thiol Chemical compound CCCCCCCCCS ZVEZMVFBMOOHAT-UHFFFAOYSA-N 0.000 description 1
- KZCOBXFFBQJQHH-UHFFFAOYSA-N octane-1-thiol Chemical compound CCCCCCCCS KZCOBXFFBQJQHH-UHFFFAOYSA-N 0.000 description 1
- IGMQODZGDORXEN-UHFFFAOYSA-N pentadecane-1-thiol Chemical compound CCCCCCCCCCCCCCCS IGMQODZGDORXEN-UHFFFAOYSA-N 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 125000001424 substituent group Chemical group 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- GEKDEMKPCKTKEC-UHFFFAOYSA-N tetradecane-1-thiol Chemical compound CCCCCCCCCCCCCCS GEKDEMKPCKTKEC-UHFFFAOYSA-N 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- HNKJADCVZUBCPG-UHFFFAOYSA-N thioanisole Chemical compound CSC1=CC=CC=C1 HNKJADCVZUBCPG-UHFFFAOYSA-N 0.000 description 1
- NBOMNTLFRHMDEZ-UHFFFAOYSA-N thiosalicylic acid Chemical compound OC(=O)C1=CC=CC=C1S NBOMNTLFRHMDEZ-UHFFFAOYSA-N 0.000 description 1
- 229940103494 thiosalicylic acid Drugs 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- IPBROXKVGHZHJV-UHFFFAOYSA-N tridecane-1-thiol Chemical compound CCCCCCCCCCCCCS IPBROXKVGHZHJV-UHFFFAOYSA-N 0.000 description 1
- CCIDWXHLGNEQSL-UHFFFAOYSA-N undecane-1-thiol Chemical compound CCCCCCCCCCCS CCIDWXHLGNEQSL-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Description
［産業上の利用分野］
本発明は、オキシ水酸化鉄または酸化鉄を還元
して得られる金属磁性粉末の表面処理法に関する
ものである。
更に詳しくは、本発明は、金属磁性粉末を表面
処理して金属磁性粉末の耐酸化性および分散性を
向上させる方法に関するものである。
［従来の技術］
オキシ水酸化鉄または酸化鉄を還元性ガス、例
えば水素で還元して得られる金属磁性粉末は、酸
化物系磁性粉末、例えばγ−Fe2O3に比べて高保
磁力、高飽和磁気モーメントを与えるので高密度
磁気記録用として期待され、一部使用されるよう
になつてきた。
しかしながら金属磁性粉末は、表面活性が大き
く、大気中に放置すると発火、燃焼の危険性があ
り、ま経時的に酸化が進行して飽和磁化が低下す
るという問題点がある。
それ故、オキシ水酸化鉄または酸化鉄を還元し
て得られる金属磁性粉末を大気中にとりだすにあ
たつては、またとりだした金属磁性粉末を各種用
途に使用するにあたつては、金属磁性粉末の表面
処理（安定化処理）が必要不可決であり、すでに
種々の表面処理法が提案されている。
例えば、(1)金属磁性粉末をトルエン、キシレン
の如き有機溶媒中に浸漬した後、有機溶媒を除々
に蒸発させて粉末粒子表面に酸化被膜を形成させ
る方法、(2)金属磁性粉末の粒子表面を含酸素不活
性ガスにより酸化して酸化被膜を形成させる方
法、(3)金属磁性粉末の表面をある種の金属元素、
金属化合物、界面活性剤、樹脂等で被覆する方法
等が提案されている。
［発明が解決しようとする問題点］
しかしながら、(1)の方法は有機溶媒の蒸発速度
等の条件により燃焼の危険があつたり、期待した
耐酸化性効果や磁気特性が得られなかつたり、塗
料化（インク化）時の分散性が劣つたりする難点
があり、(2)の方法でも分散性は十分でなく、また
記録密度の向上を図るために金属磁性粉末を微粒
子化すると耐酸化性が悪くなつたり、飽和磁化が
低下したりする難点があり、また(3)の方法は被覆
物質の選択の難しさもさることながら、たとえ耐
酸化性の向上を図ることができてもインク化時の
分散性に難点が生じたりすることが多い。
本発明は、インク化時の分散性が改善された金
属磁性粉末を提供することにある。
また本発明は、耐酸化性にすぐれた磁気特性の
よい金属磁性粉末を提供することにある。
［問題点を解決するための手段］
本発明は、オキシ水酸化鉄または酸化鉄を還元
して得られる金属磁性粉末を、微量の酸素を含有
する不活性ガス雰囲気下でアニール処理した後、
有機イオウ化合物で表面処理することを特徴とす
る金属磁性粉末の表面処理法に関するものであ
る。
本発明において表面処理される金属磁性粉末
は、それ自体公知の方法でオキシ水酸化鉄または
酸化鉄を水素の如き還元性ガス雰囲気下に300〜
500℃程度の温度で加熱還元して得られるもので
あり、金属磁性粉末には従来この種の磁気記録用
磁性粉末に用いられているNi、Co、Cr、Mn、
Cu、Zn、Ti、Ｖ等が少量含まれているものも包
含される。
本発明においては、最初に金属磁性粉末の表面
に酸化被膜を形成させる。酸化被膜の形成手段と
しては、金属磁性粉末を微量の酸素を含有する不
活性ガス雰囲気下にアニール処理する方法が用い
られる。前記以外の方法、例えば、金属磁性粉末
を適当な有機溶媒中に浸漬し、酸素含有ガスを吹
き込んで粉末粒子表面に酸化被膜を形成させる方
法は、操作が煩雑であり、また金属磁性粉末を有
機溶媒中に均一に分散させることが難しいため、
均一な酸化被膜が得られないので好ましくない、
アニール処理によつて金属磁性粉末の表面には
緻密で強固な酸化被膜を形成させることができる
ので、大気中に放置しても発火、燃焼等の危険性
はない。
不活性ガス中の酸素含有量は、50〜10000ppm、
好ましくは100〜8000ppmにするのがよい。酸素
含有量が多すぎると酸化が急速に進み緻密で強固
な酸化被膜の形成が困難になり、発火、燃焼等の
恐れもあり、また少なすぎると酸化被膜の形成に
長時間を要する。不活性ガスとしては一般に窒素
が便利に使用されるが、アルゴン、ヘリウム等そ
の他の不活性ガスを使用しても差支えない。
アニール処理する際の温度は、30〜700℃、好
ましくは100〜500℃が効果的であり、また処理時
間は１〜10時間、好ましくは２〜５時間が適当で
ある。
アニール処理した後の酸化被膜を形成させた金
属磁性粉末は、これを有機イオウ化合物で表面処
理する。この表面処理によつて金属磁性粉末の耐
酸化性および分散性を一段と向上させることがで
き、磁気特性もすぐれた金属磁性粉末が得られ
る。
本発明においては、最初に金属磁性粉末をアニ
ール処理し、次いで有機イオウ化合物で表面処理
する。有機イオウ化合物で表面処理した後にアニ
ール処理した場合には、被着した有機イオウ化合
物がアニール処理により飛散又は分解してしまう
ので好ましくない。
有機イオウ化合物としては、０，0′−ジベンズ
アミドジフエニルジスルフイド、または式Ｒ−
SH（式中Ｒは炭素数４〜20のアルキル基、フエニ
ル基、シクロヘキシル基、アリル基またはベンジ
ル基を示す。）で表わされるメルカプタン化合物
が用いられる。なお、前記式で表わされるメルカ
プタン化合物のＲがアルキル基の場合、炭素数４
〜20のものが、耐酸化性、分散性、経済性等から
みて好適に用いられる。炭素数が４より小さいも
のは常温で気体となるため、磁性粉の浸漬操作が
困難となるので好ましくない。また、炭素数が20
より大きいものは、分子が嵩張るため磁性粉の分
散効果が不十分となり、また値段も高く経済的で
ない。また、前記式で表わされるメルカプタン化
合物のＲのフエニル基は、水酸基、メチル基、カ
ルボキシル基およびハロゲン原子よりなる群から
選択された置換基を有していてもよい。メルカプ
タン化合物の代表的なものとしては、ブチルメル
カプタン、アミルメルカプタン、ヘキシルメルカ
プタン、ヘプチルメルカプタン、オクチルメルカ
プタン、ノニルメルカプタン、デシルメルカプタ
ン、ウンデシルメルカプタン、ドデシルメルカプ
タン、トリデシルメルカプタン、テトラデシルメ
ルカプタン、ペンタデシルメルカプタン、ヘキサ
デシルメルカプタン、オタタデシルメルカプタ
ン、ノナデシルメルカプタン、アラキルメルカプ
タン等の炭素数４〜20のアルキルメルカプタン、
チオフエノール、チオクレゾール、チオサリチル
酸、チオカテコール、チオアニソール、チオ安息
香酸、ｐ−メルカプトクロルベンゼン、２，４，
５−トリクロロチオフエノール等の如きフエニル
メルカプタン類、シクロヘキシルメルカプタン、
アリルメルカプタン、ベンジルメルカプタン等を
挙げることができる。
酸化被膜を形成させた金属磁性粉末を有機イオ
ウ化合物で表面処理する方法としては、粉末粒子
表面を有機イオウ化合物で均一に処理することが
できれば湿式法、乾式法等いずれの方法を採用し
てもよいが、一般には有機イオウ化合物を溶解な
いしは分散させた溶媒中に金属磁性粉末を浸漬し
た後、乾燥する湿式法を採用するのが好適であ
る。溶媒中の有機イオウ化合物の濃度は、これが
あまり高すぎると磁気特性に悪影響を及ぼした
り、操作が煩雑になつたりすることがあるので、
0.05〜10重量％以下、好ましくは0.1〜５重量％
が適当である。またその際有機イオウ化合物は金
属磁性粉末に対して0.1〜10重量％の量で使用す
るのが適当である。
浸漬して表面処理する際の温度は室温以上、好
ましくは50〜100℃程度が、また処理時間は１〜
10時間、好ましくは1.5〜７時間程度が一般に採
用される。
溶媒としては、水、有機溶媒等いずれを使用し
てもよいが一般に有機溶媒が好適に使用される。
有機溶媒としては、通常磁性塗料用溶媒として使
用されているもの、例えばベンゼン、トルエン、
キシレン、メチルエチルケトン、メチルイソブチ
ルケトン、シクロヘキサノン、ジオキサン、メチ
ルセロソルブ、エチルアルコール、プロピルアル
コール、ブチルアルコール、アセトン、テトラヒ
ドロフラン等を挙げることができる。
浸漬処理した金属磁性粉末は、これをそれ自体
公知の分離操作、例えばろ過等の方法でとり出し
て乾燥すると、有機イオウ化合物で表面処理され
た金属磁性粉末が得られる。乾燥方法としては風
乾、不活性ガス雰囲気下での乾燥、真空乾燥等特
に制限されないが、一般には室温〜50℃程度の温
度で乾燥するのが適当である。表面処理された金
属磁性粉末の粒子表面に有機イオウ化合物がどの
ような形態で結合し、被着しているのかは十分に
明らかではないが、FT−IR、ESCA等で分析す
ると鉄とイオウの強固な結合が認められる。
本発明においては、金属磁性粉末の表面に酸化
被膜を形成するアニール処理および有機イオウ化
合物による表面処理の両方の処理を併用すること
により、耐酸化性および分散性の優れた金属磁性
粉末が得られる。アニール処理のみでは耐酸化性
および分散性は十分ではなく、有機イオウ化合物
による表面処理のみでは、特に長時間酸素含有雰
囲気下に置かれた場合の耐酸化性が十分でない。
［実施例］
各例において耐酸化性の評価［σs維持率（％）］
は、60℃−90％RHの空気中に有機イオウ化合物
による表面処理後の金属磁性粉末を、１週間放置
した後に飽和磁化σs（emu／ｇ）を測定し、放置
前の飽和磁化に対する百分率で示した。
また分散性の評価［ろ過率（％）］は、有機イ
オウ化合物による表面処理後の金属磁性粉末を使
用し、第１表に示すバインダー組成にて磁性塗料
を作成し、篩目が1μのフイルターで磁性塗料を
ろ過し、磁性塗料がフイルターを通過する度合で
判定（全量通過した場合はろ過率100重量％）し
た。
[Industrial Field of Application] The present invention relates to a method for surface treatment of metal magnetic powder obtained by reducing iron oxyhydroxide or iron oxide. More specifically, the present invention relates to a method of surface-treating metal magnetic powder to improve its oxidation resistance and dispersibility. [Prior Art] Metal magnetic powder obtained by reducing iron oxyhydroxide or iron oxide with a reducing gas such as hydrogen has a higher coercive force and higher coercivity than oxide-based magnetic powder such as γ-Fe 2 O 3 . Since it provides a saturation magnetic moment, it is expected to be used for high-density magnetic recording, and has come to be used in some cases. However, metal magnetic powder has a large surface activity, and if left in the atmosphere, there is a risk of ignition or combustion, and oxidation progresses over time, resulting in a decrease in saturation magnetization. Therefore, when taking out the metal magnetic powder obtained by reducing iron oxyhydroxide or iron oxide into the atmosphere, and when using the taken out metal magnetic powder for various purposes, it is necessary to Surface treatment (stabilization treatment) of the powder is not necessary, and various surface treatment methods have already been proposed. For example, (1) a method in which metal magnetic powder is immersed in an organic solvent such as toluene or xylene, and then the organic solvent is gradually evaporated to form an oxide film on the powder particle surface; (2) a method in which an oxide film is formed on the powder particle surface; (3) The surface of the metal magnetic powder is oxidized with an oxygen-containing inert gas to form an oxide film.
Methods of coating with metal compounds, surfactants, resins, etc. have been proposed. [Problems to be Solved by the Invention] However, method (1) poses a risk of combustion depending on conditions such as the evaporation rate of the organic solvent, fails to provide the expected oxidation resistance effect and magnetic properties, and There is a drawback that the dispersibility during ink production is poor, and the dispersibility is not sufficient even with method (2).Additionally, if the metal magnetic powder is made into fine particles in order to improve the recording density, the oxidation resistance will be improved. In addition, method (3) has the disadvantage that it is difficult to select the coating material, and even if it is possible to improve oxidation resistance, it is difficult to select the coating material. Difficulties often arise in the dispersibility of An object of the present invention is to provide a metal magnetic powder with improved dispersibility when formed into an ink. Another object of the present invention is to provide a metal magnetic powder with excellent oxidation resistance and good magnetic properties. [Means for Solving the Problems] The present invention provides annealing treatment for metal magnetic powder obtained by reducing iron oxyhydroxide or iron oxide in an inert gas atmosphere containing a trace amount of oxygen.
The present invention relates to a method for surface treatment of metal magnetic powder, which is characterized by surface treatment with an organic sulfur compound. The metal magnetic powder to be surface-treated in the present invention is prepared by treating iron oxyhydroxide or iron oxide in a reducing gas atmosphere such as hydrogen with a method known per se.
It is obtained by heating reduction at a temperature of about 500℃, and the metal magnetic powder contains Ni, Co, Cr, Mn,
Those containing small amounts of Cu, Zn, Ti, V, etc. are also included. In the present invention, an oxide film is first formed on the surface of the metal magnetic powder. As a means for forming the oxide film, a method is used in which metal magnetic powder is annealed in an inert gas atmosphere containing a trace amount of oxygen. Methods other than those described above, such as immersing metal magnetic powder in a suitable organic solvent and blowing oxygen-containing gas to form an oxide film on the surface of the powder particles, require complicated operations, and Because it is difficult to disperse uniformly in the solvent,
Annealing is undesirable because a uniform oxide film cannot be obtained. Annealing can form a dense and strong oxide film on the surface of the metal magnetic powder, so it does not cause ignition, combustion, etc. even if left in the atmosphere. There is no danger. Oxygen content in inert gas is 50~10000ppm,
Preferably it is 100 to 8000 ppm. If the oxygen content is too high, oxidation will proceed rapidly, making it difficult to form a dense and strong oxide film, and there is a risk of ignition, combustion, etc. If the oxygen content is too low, it will take a long time to form the oxide film. Nitrogen is generally conveniently used as the inert gas, but other inert gases such as argon, helium, etc. may also be used. An effective temperature for annealing is 30 to 700°C, preferably 100 to 500°C, and a suitable treatment time is 1 to 10 hours, preferably 2 to 5 hours. After annealing, the metal magnetic powder on which an oxide film has been formed is surface-treated with an organic sulfur compound. By this surface treatment, the oxidation resistance and dispersibility of the metal magnetic powder can be further improved, and a metal magnetic powder with excellent magnetic properties can be obtained. In the present invention, the metal magnetic powder is first annealed and then surface treated with an organic sulfur compound. If annealing is performed after surface treatment with an organic sulfur compound, the deposited organic sulfur compound will scatter or decompose due to the annealing, which is not preferable. As the organic sulfur compound, 0,0'-dibenzamide diphenyl disulfide or the formula R-
A mercaptan compound represented by SH (wherein R represents an alkyl group having 4 to 20 carbon atoms, a phenyl group, a cyclohexyl group, an allyl group, or a benzyl group) is used. In addition, when R of the mercaptan compound represented by the above formula is an alkyl group, the number of carbon atoms is 4.
~20 is preferably used in view of oxidation resistance, dispersibility, economical efficiency, etc. If the number of carbon atoms is less than 4, it becomes a gas at room temperature, making it difficult to immerse the magnetic powder, which is not preferable. Also, the number of carbons is 20
If the size is larger, the dispersion effect of the magnetic powder will be insufficient due to bulky molecules, and the price will be high, making it uneconomical. Further, the phenyl group of R in the mercaptan compound represented by the above formula may have a substituent selected from the group consisting of a hydroxyl group, a methyl group, a carboxyl group, and a halogen atom. Typical mercaptan compounds include butyl mercaptan, amyl mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, undecyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan, Alkyl mercaptans having 4 to 20 carbon atoms, such as hexadecyl mercaptan, otatadecyl mercaptan, nonadecyl mercaptan, aralyl mercaptan,
Thiophenol, thiocresol, thiosalicylic acid, thiocatechol, thioanisole, thiobenzoic acid, p-mercaptochlorobenzene, 2,4,
Phenyl mercaptans such as 5-trichlorothiophenol, cyclohexyl mercaptan,
Examples include allyl mercaptan and benzyl mercaptan. As a method for surface treating metal magnetic powder on which an oxide film has been formed with an organic sulfur compound, either a wet method or a dry method can be used as long as the surface of the powder particles can be uniformly treated with the organic sulfur compound. However, it is generally preferable to adopt a wet method in which metal magnetic powder is immersed in a solvent in which an organic sulfur compound is dissolved or dispersed, and then dried. If the concentration of organic sulfur compounds in the solvent is too high, it may adversely affect magnetic properties or complicate operations.
0.05-10% by weight or less, preferably 0.1-5% by weight
is appropriate. In this case, it is appropriate to use the organic sulfur compound in an amount of 0.1 to 10% by weight based on the metal magnetic powder. The temperature during surface treatment by dipping is room temperature or higher, preferably about 50 to 100℃, and the treatment time is 1 to 100℃.
A period of about 10 hours, preferably about 1.5 to 7 hours is generally employed. As the solvent, any of water, organic solvents, etc. may be used, but organic solvents are generally preferably used.
Examples of organic solvents include those commonly used as solvents for magnetic paints, such as benzene, toluene,
Examples include xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, dioxane, methyl cellosolve, ethyl alcohol, propyl alcohol, butyl alcohol, acetone, and tetrahydrofuran. When the immersed metal magnetic powder is taken out by a separation operation known per se, such as filtration, and dried, a metal magnetic powder surface-treated with an organic sulfur compound is obtained. The drying method is not particularly limited and may include air drying, drying under an inert gas atmosphere, vacuum drying, etc., but it is generally appropriate to dry at a temperature of about room temperature to 50°C. Although it is not fully clear in what form organic sulfur compounds bind and adhere to the surface of the surface-treated metal magnetic powder particles, analysis using FT-IR, ESCA, etc. reveals that iron and sulfur are mixed together. A strong bond is observed. In the present invention, a metal magnetic powder with excellent oxidation resistance and dispersibility can be obtained by using both annealing treatment to form an oxide film on the surface of the metal magnetic powder and surface treatment with an organic sulfur compound. . Annealing alone does not provide sufficient oxidation resistance and dispersibility, and surface treatment alone with an organic sulfur compound does not provide sufficient oxidation resistance, especially when placed in an oxygen-containing atmosphere for a long period of time. [Example] Evaluation of oxidation resistance in each example [σs maintenance rate (%)]
The saturation magnetization σs (emu/g) of metal magnetic powder after surface treatment with an organic sulfur compound is left in air at 60°C and 90% RH for one week, and is expressed as a percentage of the saturation magnetization before leaving. Indicated. In addition, the evaluation of dispersibility [filtration rate (%)] was performed by using metal magnetic powder that had been surface-treated with an organic sulfur compound, creating a magnetic paint with the binder composition shown in Table 1, and using a filter with a sieve mesh of 1μ. The magnetic paint was filtered using a filter, and judgment was made based on the degree to which the magnetic paint passed through the filter (if the entire amount passed, the filtration rate was 100% by weight).
【表】【table】
【表】
実施例 １
針状のオキシ水酸化鉄粉末を650℃で脱水後、
水素雰囲気下に400℃で８時間還元して、針状の
金属磁性粉末（長軸0.2μｍ、軸比８〜10、比表面
積50m2／ｇ）を得、雰囲気を水素から窒素に切り
換えて室温まで降温し、再び徐々に昇温させなが
ら、酸素含有量100ppmの窒素ガスを流通させ、
350℃の温度で６時間保持し、金属磁性粉末の表
面に緻密な酸化被膜を形成させた。
次いで酸化被膜を形成させた金属磁性粉末10ｇ
を、ｏ，o′−ジベンズアミドジフエニルジスルフ
イド0.5ｇを、トルエン200mlに溶解させた溶液中
に浸漬し、十分に撹拌、分散させ、80℃の温度に
２時間保持して表面処理を行つた後、処理液を室
温まで下げて金属磁性粉末をろ別し、40℃の温度
で真空乾燥した。
得られた表面処理金属磁性粉末の表面をFT−
IRおよびESCAにより分析した結果、鉄とイオウ
の強固な結合が認められた。
金属磁性粉末（酸化被膜形成前および形成後、
有機イオウ化合物による表面処理後）（保磁力Hc
および飽和磁化σs）の磁気特性、耐酸化性および
分散性の評価結果等を第３表に示す。
実施例 ２〜９
実施例１と同様にして針状のオキシ水酸化鉄を
脱水後、水素雰囲気下に還元して針状の金属磁性
粉末にした後、酸化被膜を形成させる際の温度を
第２表記載の温度にしたほかは実施例１と同様に
して酸化被膜を形成させ、次いで第２表記載の有
機イオウ化合物および溶媒を用いたほかは実施例
１と同様にして有機イオウ化合物で表面処理した
金属磁性粉末を得た。
得られた表面処理金属磁性粉末の表面をFT−
IRおよびESCAにより分析した結果、鉄とイオウ
の強固な結合が認められた。
金属磁性粉末の測定結果は第３表に示す。[Table] Example 1 After dehydrating needle-shaped iron oxyhydroxide powder at 650℃,
The material was reduced in a hydrogen atmosphere at 400°C for 8 hours to obtain acicular magnetic metal powder (major axis 0.2 μm, axial ratio 8-10, specific surface area 50 m 2 /g), and the atmosphere was changed from hydrogen to nitrogen and kept at room temperature. While gradually increasing the temperature again, nitrogen gas with an oxygen content of 100 ppm is passed through.
The temperature was maintained at 350°C for 6 hours to form a dense oxide film on the surface of the metal magnetic powder. Next, 10g of metal magnetic powder on which an oxide film was formed
was immersed in a solution of 0.5 g of o,o'-dibenzamide diphenyl disulfide dissolved in 200 ml of toluene, thoroughly stirred and dispersed, and kept at a temperature of 80°C for 2 hours to perform surface treatment. After the treatment, the treatment solution was cooled to room temperature, the metal magnetic powder was filtered off, and the powder was vacuum-dried at a temperature of 40°C. The surface of the obtained surface-treated metal magnetic powder was FT-
Analysis by IR and ESCA revealed a strong bond between iron and sulfur. Metal magnetic powder (before and after oxide film formation,
After surface treatment with organic sulfur compound) (coercive force Hc
Table 3 shows the evaluation results of magnetic properties, oxidation resistance, and dispersibility (and saturation magnetization σs). Examples 2 to 9 After dehydrating acicular iron oxyhydroxide in the same manner as in Example 1, reducing it to acicular magnetic metal powder in a hydrogen atmosphere, the temperature at which the oxide film was formed was adjusted to An oxide film was formed in the same manner as in Example 1, except that the temperatures listed in Table 2 were used, and then the surface was coated with an organic sulfur compound in the same manner as in Example 1, except that the organic sulfur compounds and solvents listed in Table 2 were used. A treated metal magnetic powder was obtained. The surface of the obtained surface-treated metal magnetic powder was FT-
Analysis by IR and ESCA revealed a strong bond between iron and sulfur. The measurement results for the metal magnetic powder are shown in Table 3.
【表】【table】
【表】【table】
【表】
比較例 １
ｏ，o′−ジベンズアミドジフエニルジスルフイ
ドによる表面処理をしなかつたほかは、実施例１
と同様にして針状のオキシ水酸化鉄から酸化被膜
を形成させた金属磁性粉末を得た。
金属磁性粉末の測定結果は第４表に示す。
比較例 ２
実施例１と同様にして針状のオキシ水酸化鉄を
脱水後、水素雰囲気下に還元して針状の金属磁性
粉末にした。
次いで金属磁性粉末10ｇをトルエン200ml中に
浸漬し、十分に撹拌、分散させ、室温にて空気を
350ml／minの流量で５分間吹きこんで表面に酸
化被膜を形成させ、トルエンを除去後、風乾して
酸化被膜を形成させた金属磁性粉末を得た。
金属磁性粉末の測定結果第４表に示す。
比較例 ３
実施例１と同様にして針状のオキシ水酸化鉄を
脱水後、水素雰囲気下に還元して針状の金属磁性
粉末にした。
次いで金属磁性粉末10ｇを0.5wt％のシリコン
オイルを含むトルエン溶液に浸漬し、十分に撹
拌、分散させ、５時間保持した後、トルエン溶液
を除去し、風乾してシリコンオイルで処理した金
属磁性粉末を得た。
金属磁性粉末の測定結果は第４表に示す。
比較例 ４
実施例１と同様にして針状のオキシ水酸化鉄を
脱水後、水素雰囲気下に還元して針状の金属磁性
粉末にした。
次いで、金属磁性粉末10ｇを、アリルメルカプ
タン0.5ｇを、トルエン200mlに溶解させた溶液中
に浸漬し、十分に撹拌、分散させ、80℃の温度に
２時間保持して表面処理を行つた後、処理液を室
温まで下げて金属磁性粉末をろ別し、40℃の温度
で真空乾燥した。
得られた金属磁性粉末の測定結果は第４表に示
す。
比較例 ５
比較例２で得られた金属磁性粉末10ｇを、アリ
ルメルカプタン0.5ｇを、トルエン200mlに溶解さ
せた溶液中に浸漬し、十分に撹拌、分散させ、80
℃の温度に２時間保持して表面処理を行つた後、
処理液を室温まで下げて金属磁性粉末をろ別し、
40℃の温度で真空乾燥した。
得られた金属磁性粉末の測定結果は第４表に示
す。[Table] Comparative Example 1 Example 1 except that the surface treatment with o,o'-dibenzamide diphenyl disulfide was not performed.
In the same manner as above, a metal magnetic powder on which an oxide film was formed was obtained from needle-shaped iron oxyhydroxide. The measurement results for the metal magnetic powder are shown in Table 4. Comparative Example 2 In the same manner as in Example 1, acicular iron oxyhydroxide was dehydrated and then reduced in a hydrogen atmosphere to obtain acicular magnetic metal powder. Next, 10 g of metal magnetic powder was immersed in 200 ml of toluene, thoroughly stirred and dispersed, and air was removed at room temperature.
The mixture was blown at a flow rate of 350 ml/min for 5 minutes to form an oxide film on the surface, and after removing toluene, it was air-dried to obtain metal magnetic powder with an oxide film formed thereon. Table 4 shows the measurement results for the metal magnetic powder. Comparative Example 3 In the same manner as in Example 1, acicular iron oxyhydroxide was dehydrated and then reduced in a hydrogen atmosphere to obtain acicular magnetic metal powder. Next, 10 g of metal magnetic powder was immersed in a toluene solution containing 0.5 wt% silicone oil, thoroughly stirred and dispersed, and held for 5 hours. After removing the toluene solution and air-drying it, the metal magnetic powder was treated with silicone oil. I got it. The measurement results for the metal magnetic powder are shown in Table 4. Comparative Example 4 In the same manner as in Example 1, acicular iron oxyhydroxide was dehydrated and then reduced in a hydrogen atmosphere to obtain acicular magnetic metal powder. Next, 10 g of metal magnetic powder was immersed in a solution of 0.5 g of allyl mercaptan dissolved in 200 ml of toluene, thoroughly stirred and dispersed, and kept at a temperature of 80°C for 2 hours to perform surface treatment. The treatment liquid was cooled to room temperature, the metal magnetic powder was filtered off, and the powder was vacuum dried at a temperature of 40°C. The measurement results of the obtained metal magnetic powder are shown in Table 4. Comparative Example 5 10 g of the metal magnetic powder obtained in Comparative Example 2 was immersed in a solution of 0.5 g of allyl mercaptan dissolved in 200 ml of toluene, thoroughly stirred and dispersed, and
After surface treatment by holding at a temperature of ℃ for 2 hours,
The treatment solution is lowered to room temperature and the metal magnetic powder is filtered out.
Vacuum drying was performed at a temperature of 40°C. The measurement results of the obtained metal magnetic powder are shown in Table 4.
【表】
実施例 10
金属磁性粉末の長時間の耐酸化性を調べるた
め、実施例７で得られた金属磁性粉末、及び比較
のため比較例１、比較例４、比較例５で得られた
金属磁性粉末を60℃−90％RHの空気中に１ケ月
放置した後の飽和磁化の変化を測定した。[Table] Example 10 In order to investigate the long-term oxidation resistance of metal magnetic powder, the metal magnetic powder obtained in Example 7 and the metal magnetic powder obtained in Comparative Example 1, Comparative Example 4, and Comparative Example 5 were used for comparison. After the metal magnetic powder was left in air at 60°C and 90% RH for one month, the change in saturation magnetization was measured.
【表】
［発明の効果］
本発明の表面処理法によると耐酸化性および分
散性のすぐれた金属磁性粉末が得られる。[Table] [Effects of the Invention] According to the surface treatment method of the present invention, a metal magnetic powder with excellent oxidation resistance and dispersibility can be obtained.
Claims (1)
れる金属磁性粉末を、微量の酸素を含有する不活
性ガス雰囲気下にアニール処理した後、０，0′−
ジベンズアミドジフエニルジスルフイド、または
式Ｒ−SH（式中Ｒは炭素数４〜20のアルキル基、
フエニル基、シクロヘキシル基、アリル基または
ベンジル基を示す。）で表わされるメルカプタン
化合物で表面処理することを特徴とする金属磁性
粉末の表面処理法。 ２ 微量の酸素を含有する不活性ガスの酸素含有
量が50〜10000ppmである特許請求の範囲第１項
記載の金属磁性粉末の表面処理法。[Claims] 1. Metal magnetic powder obtained by reducing iron oxyhydroxide or iron oxide is annealed in an inert gas atmosphere containing a trace amount of oxygen, and then 0,0'-
Dibenzamide diphenyl disulfide, or a compound of the formula R-SH (wherein R is an alkyl group having 4 to 20 carbon atoms,
Indicates a phenyl group, cyclohexyl group, allyl group or benzyl group. ) A method for surface treatment of metal magnetic powder, characterized by surface treatment with a mercaptan compound represented by: 2. The method for surface treatment of metal magnetic powder according to claim 1, wherein the inert gas containing a trace amount of oxygen has an oxygen content of 50 to 10,000 ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59175151A JPS6156201A (en) | 1984-08-24 | 1984-08-24 | Surface treatment of magnetic metallic powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59175151A JPS6156201A (en) | 1984-08-24 | 1984-08-24 | Surface treatment of magnetic metallic powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6156201A JPS6156201A (en) | 1986-03-20 |
| JPH0148323B2 true JPH0148323B2 (en) | 1989-10-18 |
Family
ID=15991160
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59175151A Granted JPS6156201A (en) | 1984-08-24 | 1984-08-24 | Surface treatment of magnetic metallic powder |
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| Country | Link |
|---|---|
| JP (1) | JPS6156201A (en) |
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| JPH0262829A (en) * | 1988-05-18 | 1990-03-02 | Nippon Kayaku Co Ltd | Preventive and remedy for trauma caused by ischemia |
| JP4623981B2 (en) * | 2004-03-12 | 2011-02-02 | 大研化学工業株式会社 | Method for producing metal ultrafine particles |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5378096A (en) * | 1976-12-20 | 1978-07-11 | Hitachi Maxell | Magnetic metal powder for magnetic recording and method of manufacturing same |
| JPS5635721A (en) * | 1980-05-26 | 1981-04-08 | Nippon Steel Corp | Production of steel material of good cold workability |
| JPS56142801A (en) * | 1980-03-18 | 1981-11-07 | Hitachi Maxell Ltd | Treatment of metallic powder |
| JPS5852523A (en) * | 1981-09-24 | 1983-03-28 | Ishida Scales Mfg Co Ltd | Automatic weighing device |
| JPS58221203A (en) * | 1982-06-18 | 1983-12-22 | Tdk Corp | Magnetic powder having improved dispersibility |
-
1984
- 1984-08-24 JP JP59175151A patent/JPS6156201A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5378096A (en) * | 1976-12-20 | 1978-07-11 | Hitachi Maxell | Magnetic metal powder for magnetic recording and method of manufacturing same |
| JPS56142801A (en) * | 1980-03-18 | 1981-11-07 | Hitachi Maxell Ltd | Treatment of metallic powder |
| JPS5635721A (en) * | 1980-05-26 | 1981-04-08 | Nippon Steel Corp | Production of steel material of good cold workability |
| JPS5852523A (en) * | 1981-09-24 | 1983-03-28 | Ishida Scales Mfg Co Ltd | Automatic weighing device |
| JPS58221203A (en) * | 1982-06-18 | 1983-12-22 | Tdk Corp | Magnetic powder having improved dispersibility |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6156201A (en) | 1986-03-20 |
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