JPH0239017B2 - - Google Patents
Info
- Publication number
- JPH0239017B2 JPH0239017B2 JP56038952A JP3895281A JPH0239017B2 JP H0239017 B2 JPH0239017 B2 JP H0239017B2 JP 56038952 A JP56038952 A JP 56038952A JP 3895281 A JP3895281 A JP 3895281A JP H0239017 B2 JPH0239017 B2 JP H0239017B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- rust preventive
- oxygen
- naphthol
- naphthols
- 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 - Lifetime
Links
- 239000010409 thin film Substances 0.000 claims description 25
- 230000005294 ferromagnetic effect Effects 0.000 claims description 18
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 14
- 239000001301 oxygen Substances 0.000 claims description 14
- 229910052760 oxygen Inorganic materials 0.000 claims description 14
- 230000003449 preventive effect Effects 0.000 claims description 13
- 239000003795 chemical substances by application Substances 0.000 claims description 11
- 230000005291 magnetic effect Effects 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 150000004780 naphthols Chemical class 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 3
- 238000005260 corrosion Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 6
- 229910002441 CoNi Inorganic materials 0.000 description 5
- 239000010410 layer Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910001882 dioxygen Inorganic materials 0.000 description 3
- 239000003112 inhibitor Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- -1 nitro- Chemical class 0.000 description 3
- NHEVNUARLCWEED-UHFFFAOYSA-N 1,4,5-Naphthalenetriol Chemical compound C1=CC=C2C(O)=CC=C(O)C2=C1O NHEVNUARLCWEED-UHFFFAOYSA-N 0.000 description 2
- KJCVRFUGPWSIIH-UHFFFAOYSA-N 1-naphthol Chemical group C1=CC=C2C(O)=CC=CC2=C1 KJCVRFUGPWSIIH-UHFFFAOYSA-N 0.000 description 2
- JWAZRIHNYRIHIV-UHFFFAOYSA-N 2-naphthol Chemical compound C1=CC=CC2=CC(O)=CC=C21 JWAZRIHNYRIHIV-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229920006267 polyester film Polymers 0.000 description 2
- VFLQOIOBRZOQRY-UHFFFAOYSA-N 1,6-dinitronaphthalen-2-ol Chemical compound C1=C([N+]([O-])=O)C=CC2=C([N+]([O-])=O)C(O)=CC=C21 VFLQOIOBRZOQRY-UHFFFAOYSA-N 0.000 description 1
- FHMMQQXRSYSWCM-UHFFFAOYSA-N 1-aminonaphthalen-2-ol Chemical compound C1=CC=C2C(N)=C(O)C=CC2=C1 FHMMQQXRSYSWCM-UHFFFAOYSA-N 0.000 description 1
- RMSOEGBYNWXXBG-UHFFFAOYSA-N 1-chloronaphthalen-2-ol Chemical compound C1=CC=CC2=C(Cl)C(O)=CC=C21 RMSOEGBYNWXXBG-UHFFFAOYSA-N 0.000 description 1
- SSHIVHKMGVBXTJ-UHFFFAOYSA-N 1-nitronaphthalen-2-ol Chemical compound C1=CC=CC2=C([N+]([O-])=O)C(O)=CC=C21 SSHIVHKMGVBXTJ-UHFFFAOYSA-N 0.000 description 1
- YXAOOTNFFAQIPZ-UHFFFAOYSA-N 1-nitrosonaphthalen-2-ol Chemical compound C1=CC=CC2=C(N=O)C(O)=CC=C21 YXAOOTNFFAQIPZ-UHFFFAOYSA-N 0.000 description 1
- HVLJEMXDXOTWLV-UHFFFAOYSA-N 2,4-dichloronaphthalen-1-ol Chemical compound C1=CC=C2C(O)=C(Cl)C=C(Cl)C2=C1 HVLJEMXDXOTWLV-UHFFFAOYSA-N 0.000 description 1
- SYUYTOYKQOAVDW-UHFFFAOYSA-N 2-nitrosonaphthalen-1-ol Chemical compound C1=CC=C2C(O)=C(N=O)C=CC2=C1 SYUYTOYKQOAVDW-UHFFFAOYSA-N 0.000 description 1
- 229910020630 Co Ni Inorganic materials 0.000 description 1
- 229910002440 Co–Ni Inorganic materials 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910017709 Ni Co Inorganic materials 0.000 description 1
- 229910003267 Ni-Co Inorganic materials 0.000 description 1
- 229910003262 Ni‐Co Inorganic materials 0.000 description 1
- 150000008062 acetophenones Chemical class 0.000 description 1
- 239000000654 additive 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
- 239000013556 antirust agent Substances 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 235000019441 ethanol Nutrition 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- JHBCAOBRUPIFBZ-UHFFFAOYSA-N naphthalene-1,2,5,8-tetrol Chemical compound OC1=CC=C(O)C2=C(O)C(O)=CC=C21 JHBCAOBRUPIFBZ-UHFFFAOYSA-N 0.000 description 1
- NXPPAOGUKPJVDI-UHFFFAOYSA-N naphthalene-1,2-diol Chemical compound C1=CC=CC2=C(O)C(O)=CC=C21 NXPPAOGUKPJVDI-UHFFFAOYSA-N 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 150000004053 quinones Chemical class 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
- G11B5/658—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing oxygen, e.g. molecular oxygen or magnetic oxide
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Magnetic Record Carriers (AREA)
Description
本発明は高湿度中での耐食性が改善された強磁
性金属薄膜型磁気記録媒体に関するものである。
ポリエステル、ポリイミド等のプラスチツクフ
イルムや、アルミ板、ガラス板等の非磁性材料か
ら成る基板の表面に、真空中で蒸着、イオンプレ
ーテイング、スパツタリング等によりFe，Ni，
Coあるいはこれらの合金を主体とし酸素を含む
強磁性薄膜を形成せしめた磁気記録媒体は、ビデ
オ信号記録のごとき高密度記録に適したものであ
るが、強磁性金属薄膜の膜厚が0.05〜0.5μmと小
さいために高湿度中、とくに温度変化が大きく結
露が発生するような環境下で放置された場合表面
に腐食を生じやすくその腐食がある程度進行する
と、電磁性変換特性に影響を及ぼし、またヘツド
タツチ、耐摩耗性等の実用特性を劣化させる。こ
の腐食を防錆剤で抑制する場合、ヘツド・磁性層
間のスペーシングロスの関係で磁性層表面に形成
し得る保護膜の厚さにも厳しい制限があるため数
分子層程度の付着または吸着で充分効果のある防
錆剤が望まれていた。Fe，Ni，Coあるいはそれ
らの合金を主体とし酸素を含む強磁性薄膜はそれ
らの純金属から成る薄膜に比べて抗磁力が高く、
耐食性も秀れているものであるが、酸素が含有さ
れていること、すなわち部分的に酸化されている
ために、防錆効果を発揮する材料―防錆剤―も
Fe，Co，Ni等のバルク金属に用いられる公知の
ものが必ずしも適当であるとはいえず、実際それ
らの防錆剤を適用してみると逆に腐食を促進させ
る場合もあるため、新たに、酸素を含む強磁性薄
膜に適合するものを探すことが必要となつた。そ
こで、本発明者らが種々検討した結果、酸素を含
む強磁性薄膜に対する防錆剤として、ナフトール
類を主成分とするものが適当であることを見出し
た。すなわち本発明は、非磁性基板上に酸素を含
む強磁性金属薄膜を形成せしめた磁気記録媒体に
おいて、上記強磁性金属薄膜に、ナフトール類を
主成分とする防錆剤を付着せしめたことを特徴と
するものである。
非磁性基板としては、ポリエステルフイルム、
ポリイミドフイルム等のプラスチツクフイルム、
アルミ板、ステンレス板などの金属板、ガラス板
のような無機質の板などが用いられ、これらの上
に直接あるいは非磁性薄膜層を介して、微量の酸
素ガスの存在する真空中で蒸着、スパツタ、イオ
ンプレーテイングなどの方法で針めあるいは垂直
柱状結晶から成る厚さ0.05〜0.5μmのCo，Fe，
Fe―Ni，Co―Ni，Fe―Co，Fe―Ni―Co等を主
体とし酸素を磁性金属との原子比で３〜45％含有
する単層あるいは多層の強磁性薄膜を形成せしめ
たものにナフトール類を主成分とする防錆剤を適
用する。本発明におけるナフトール類とは、α―
ナフトール、β―ナフトール、１，２―ナフタレ
ンジオール、１，４，５―ナフタレントリオー
ル、１，２，５，８―ナフタレンテトラオール等
の純ナフトール類および、ニトロ、ニトロソ、ア
ミノ、ハロゲノ置換ナフトール類、たとえば、１
―クロロ―２―ナフトール、２，４―ジクロロ―
１―ナフトール、１―ニトロ―２―ナフトール、
１，６―ジニトロ―２―ナフトール、１―ニトロ
ソ―２―ナフトール、２―ニトロソ―１―ナフト
ール、１―アミノ―２―ナフトール、等を指すも
のである。そして本発明における防錆剤は、これ
らの単体、あるいは２種以上の混合体を主体とし
（少くとも50％以上含有）必要に応じてナフトー
ル類以外の有機化合物、たとえば、キノン類、ア
ルキルフエノール類、二価フエノール類、アセト
フエノン類等を添加したものである。
これらの防錆剤は、強磁性薄膜の少くとも表
面、可能であれば内部、あるいは強磁性薄膜が形
成されている下地との界面に接する状態で存在せ
しめることにより、その効果を発揮せしめる。そ
の適量は磁気記録媒体１m2当り0.5〜500mg程度で
ある。具体的な存在のさせ方としては、防錆剤を
それ自体、あるいは高分子化合物等の被膜形成能
を有するものに混合せしめた状態で必要ならば溶
剤で希釈して強磁性薄膜表面に塗布する方法、防
錆剤の蒸気を強磁性薄膜表面にあてる方法、さら
に、磁気記録媒体がテープ状である場合にはその
裏面に存在せしめておきテープが巻込まれたとき
強磁性薄膜表面に転写せしめるようにする方法、
等公知の手段を用いることができる。また、防錆
剤と共に、通常の潤滑剤、帯電防止剤等の添加剤
を用いることも可能である。
次に具体的に本発明の実施例について説明す
る。
厚さ10μmのポリエステルフイルムを円筒キヤ
ンの周面上に沿わせて５×10-5Torrの真空度で
酸素ガスを0.3／mmの速度で導入して電子ビー
ム加熱により溶融したCoNi合金（Ni含有量20wt
％）を連続斜め蒸着（低入射角度成分30゜以下カ
ツト）し、厚さ、1000Åの酸素含有CoNi強磁性
薄膜をフイルム上に形成せしめたもの（試料Ａ）
と、上記と類似の条件で真空度５×10-6Torr、
酸素ガス導入なしで酸素を含有せしめないCoNi
強磁性薄膜を形成せしめたもの（試料Ｂ）を用意
した。膜中の酸素量をオージエ電子分光分析法を
主体に測定した結果、試料Ａの膜中の平均酸素量
はCoとNiに対する原子数比（Ｏ／Co＋Ni×100）で
10％であり、試料Ｂのそれは１％以下であつた。
これらの試料表面にナフトール類を主体とする防
錆剤をエチルアルコール、アセトン、トルエン等
に溶解せしめて塗布乾燥（塗布量は10〜100mg／
m2となるよう調節した。）したのち50℃、90％R.
H.雰囲気中に放置し、その間、定期的に取出し
顕微鏡観察することにより錆発生状態を調べた。
その結果を表に示す。表より明らかなようにナフ
トール類を主体とする防錆剤は酸素を含むCoNi
薄膜に対し防鏡効果が大であつた。この効果は酸
素含有量３〜45％のCoNi薄膜（Ni10〜55wt％）
では同様であり、Co薄膜、Fe―Ni薄膜、Fe―
Co薄膜等においても類似していた。
The present invention relates to a ferromagnetic metal thin film magnetic recording medium with improved corrosion resistance in high humidity. Fe, Ni, Ni,
A magnetic recording medium in which a ferromagnetic thin film mainly composed of Co or an alloy thereof and containing oxygen is formed is suitable for high-density recording such as video signal recording, but the thickness of the ferromagnetic metal thin film is 0.05 to 0.5 Because it is small in size (μm), if it is left in high humidity environments, especially in environments where there are large temperature changes and condensation, the surface tends to corrode, and if the corrosion progresses to a certain extent, it will affect the electromagnetic conversion characteristics. Deteriorates practical properties such as head touch and wear resistance. When suppressing this corrosion with a rust preventive, there are strict limitations on the thickness of the protective film that can be formed on the surface of the magnetic layer due to spacing loss between the head and the magnetic layer, so only a few molecular layers can be attached or adsorbed. A sufficiently effective rust preventive agent was desired. Ferromagnetic thin films made mainly of Fe, Ni, Co, or their alloys and containing oxygen have higher coercive force than thin films made of these pure metals.
It has excellent corrosion resistance, but because it contains oxygen, that is, it is partially oxidized, it is also a material that exhibits a rust prevention effect (rust inhibitor).
Known anti-rust agents used for bulk metals such as Fe, Co, and Ni are not necessarily suitable, and when applied, they may actually accelerate corrosion. , it became necessary to find something compatible with ferromagnetic thin films containing oxygen. As a result of various studies, the inventors of the present invention found that a rust preventive agent containing naphthols as a main component is suitable as a rust preventive agent for a ferromagnetic thin film containing oxygen. That is, the present invention is a magnetic recording medium in which a ferromagnetic metal thin film containing oxygen is formed on a non-magnetic substrate, characterized in that a rust preventive agent containing naphthols as a main component is attached to the ferromagnetic metal thin film. That is. Non-magnetic substrates include polyester film,
Plastic films such as polyimide films,
Metal plates such as aluminum plates and stainless steel plates, inorganic plates such as glass plates, etc. are used, and evaporation or sputtering is performed on these plates directly or through a non-magnetic thin film layer in a vacuum in the presence of a trace amount of oxygen gas. Co, Fe, with a thickness of 0.05 to 0.5 μm, consisting of needle or vertical columnar crystals, by ion plating or other methods.
A single-layer or multi-layer ferromagnetic thin film mainly composed of Fe-Ni, Co-Ni, Fe-Co, Fe-Ni-Co, etc. and containing oxygen in an atomic ratio of 3 to 45% with respect to the magnetic metal. Apply a rust inhibitor whose main ingredient is naphthol. The naphthols in the present invention are α-
Pure naphthols such as naphthol, β-naphthol, 1,2-naphthalenediol, 1,4,5-naphthalenetriol, 1,2,5,8-naphthalenetetraol, and nitro-, nitroso-, amino-, and halogeno-substituted naphthols , for example, 1
-Chloro-2-naphthol, 2,4-dichloro-
1-naphthol, 1-nitro-2-naphthol,
It refers to 1,6-dinitro-2-naphthol, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 1-amino-2-naphthol, and the like. The rust preventive agent in the present invention is mainly composed of these alone or a mixture of two or more thereof (containing at least 50%), and optionally containing organic compounds other than naphthols, such as quinones and alkylphenols. , divalent phenols, acetophenones, etc. These rust preventive agents exhibit their effects by being present at least on the surface of the ferromagnetic thin film, if possible inside, or in contact with the interface with the base on which the ferromagnetic thin film is formed. The appropriate amount is about 0.5 to 500 mg per m 2 of magnetic recording medium. Specifically, the rust preventive agent is applied on the surface of the ferromagnetic thin film, either by itself or mixed with a film-forming agent such as a polymer compound, diluted with a solvent if necessary. A method in which rust preventive vapor is applied to the surface of a ferromagnetic thin film, and a method in which rust preventive vapor is applied to the surface of a ferromagnetic thin film; how to,
Well-known means such as the following can be used. In addition to the rust preventive agent, it is also possible to use ordinary lubricants, antistatic agents, and other additives. Next, embodiments of the present invention will be specifically described. A CoNi alloy (containing Ni) was melted by electron beam heating by placing a 10 μm thick polyester film along the circumferential surface of a cylindrical can and introducing oxygen gas at a rate of 0.3/mm in a vacuum of 5 × 10 -5 Torr. Amount 20wt
%) was continuously obliquely deposited (cutting the low incident angle component below 30°) to form an oxygen-containing CoNi ferromagnetic thin film with a thickness of 1000 Å on the film (Sample A).
And under similar conditions as above, the degree of vacuum is 5×10 -6 Torr,
CoNi that does not contain oxygen without introducing oxygen gas
A sample (sample B) on which a ferromagnetic thin film was formed was prepared. As a result of measuring the amount of oxygen in the film mainly using Auger electron spectroscopy, it was found that the average amount of oxygen in the film of Sample A was 10% in terms of atomic ratio (O/Co+Ni×100) to Co and Ni, and that of Sample B. It was less than 1%.
A rust preventive agent mainly composed of naphthols is dissolved in ethyl alcohol, acetone, toluene, etc. on the surface of these samples and dried (applying amount is 10 to 100 mg/day).
It was adjusted so that it was m2 . ) and then 50℃, 90% R.
H. The specimen was left in an atmosphere, during which time it was periodically taken out and observed under a microscope to examine the state of rust formation.
The results are shown in the table. As is clear from the table, rust inhibitors mainly containing naphthols are CoNi containing oxygen.
The anti-mirror effect was greater than that of a thin film. This effect is due to CoNi thin film with oxygen content of 3 to 45% (Ni 10 to 55wt%).
The same is true for Co thin film, Fe―Ni thin film, Fe―
Similar results were observed for Co thin films.
【表】【table】
【表】
以上に説明したように本発明によると高湿度中
での耐食性を容易に改善することができる。[Table] As explained above, according to the present invention, corrosion resistance in high humidity can be easily improved.
Claims (1)
形成せしめた磁気記録媒体において、上記強磁性
金属薄膜にナフトール類を主成分とする防錆剤を
付着せしめたことを特徴とする磁気記録媒体。1. A magnetic recording medium in which a ferromagnetic metal thin film containing oxygen is formed on a non-magnetic substrate, characterized in that a rust preventive agent containing naphthols as a main component is attached to the ferromagnetic metal thin film. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56038952A JPS57152520A (en) | 1981-03-17 | 1981-03-17 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56038952A JPS57152520A (en) | 1981-03-17 | 1981-03-17 | Magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57152520A JPS57152520A (en) | 1982-09-20 |
| JPH0239017B2 true JPH0239017B2 (en) | 1990-09-03 |
Family
ID=12539529
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56038952A Granted JPS57152520A (en) | 1981-03-17 | 1981-03-17 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57152520A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60154323A (en) * | 1984-01-20 | 1985-08-14 | Sony Corp | Magnetic recording medium |
-
1981
- 1981-03-17 JP JP56038952A patent/JPS57152520A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57152520A (en) | 1982-09-20 |
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|---|---|---|
| JPH0253849B2 (en) | ||
| US5853871A (en) | Magnetic recording medium | |
| JPH0239017B2 (en) | ||
| JPS58194133A (en) | magnetic recording medium | |
| JPS58194136A (en) | Magnetic recording medium | |
| JPS58194135A (en) | Magnetic recording medium | |
| JPS58222441A (en) | magnetic recording medium | |
| JPH033288B2 (en) | ||
| JPS58188333A (en) | magnetic recording medium | |
| JPS58188332A (en) | Magnetic recording medium | |
| JPS593725A (en) | magnetic recording medium | |
| JPS6089815A (en) | magnetic recording medium | |
| JPH028375B2 (en) | ||
| JPS58194134A (en) | magnetic recording medium | |
| JPS593724A (en) | magnetic recording medium | |
| JPS593726A (en) | magnetic recording medium | |
| JPS624774B2 (en) | ||
| JPS58194138A (en) | Magnetic recording medium | |
| JPS58222440A (en) | Magnetic recording medium | |
| JPS6365604A (en) | Iron magnetic film | |
| JPH0130224B2 (en) | ||
| JPS58194140A (en) | Magnetic recording medium | |
| JPS58188331A (en) | magnetic recording medium | |
| JPS58222443A (en) | magnetic recording medium | |
| JPS59142743A (en) | Magnetic recording medium |