JPS62192918A - Magnetic disk - Google Patents

Abstract

PURPOSE:To satisfy both an output characteristic and contact start stop attraction characteristic by providing a piece of a groove which intersect at a specific angle with a circle concentrical with the center of a disk and is limited in width and depth onto an anodically oxidized film to the specific width in the region where the slider of a magnetic head moves. CONSTITUTION:At least a piece of the groove which intersects at 0-45 deg. with the circle concentrical with the center of the disk and has 0.1-2mum width and 0.005-0.3mum depth is provided onto the anodically oxidizied film at 10mum in the region where the slider of the magnetic head moves. There is no significant difference in the attraction characteristic as compared to the disk having no groove if the depth of the groove is <=0.005mum. The magnetic film provided to the bottom of the groove no longer senses the magnetic field of the head and such is not preferable for the overwrite characteristic of the output and noise if the depth is >=0.3mum. The angle of the groove intersecting with the circumferential direction of the disk is preferably 45 deg., ore particularly preferably 2-5 deg. in order to form the thin film magnetic disk for the subtantially higher density recording.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、電子計算機の記憶装置として用いられる磁気
ディスクに関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk used as a storage device for an electronic computer.

〔従来の技術〕[Conventional technology]

現在広く用いられている磁気ディスク装置のディスクは
塗布型と称し、アルミニウム合金を鏡面加工した後、磁
性粉と硬質物質とを樹脂とともに塗布し、その上に潤滑
剤を付けたディスクである。The disks of magnetic disk drives that are currently widely used are called coated type disks, which are made by mirror-finishing aluminum alloy, then applying magnetic powder and hard material together with resin, and applying lubricant on top.

これは、磁性粉が不連続に分散しているためノイズが大
きい。そこで、磁性体をスパッタ法もしくはメッキ法に
よって付与した連結連続磁性体を有するディスクが開発
され、一部用いられている。This has large noise because the magnetic powder is discontinuously dispersed. Therefore, disks having connected continuous magnetic bodies to which magnetic bodies are applied by sputtering or plating have been developed and are now in some use.

しかし、この開発品は、塗布型のディスクのように、磁
性体の不連続をもたらす硬質物質を樹脂中に一部混入す
ることができないため、ヘッドの０８８（コンタクトス
タートストップ）方式による離着陸時の衝撃を、柔らか
いアルミニウム合金でうけると磁性膜が破損してしまう
。そこで、アルミニウム合金に硬質下地膜を全面に付け
た後、これを鏡面加工することが一般的になった。硬質
下地膜としては、無電解ニッケルメッキ膜と陽極酸化膜
とが広く知られている。つまりアルミニウム合金を形状
加工しその表面にこれらの下地膜を付与して再度、その
表面を鏡面加工後、上記連続磁性体および保護膜、＠滑
脱を付与するのである。However, unlike coated disks, this developed product cannot partially mix into the resin a hard substance that causes discontinuity in the magnetic material, so the 088 (contact start/stop) head system is used during takeoff and landing. If a soft aluminum alloy is subjected to impact, the magnetic film will be damaged. Therefore, it has become common practice to apply a hard base film to the entire surface of the aluminum alloy and then mirror-finish it. As hard base films, electroless nickel plating films and anodic oxide films are widely known. In other words, the aluminum alloy is shaped, these base films are applied to its surface, the surface is polished again to a mirror finish, and then the continuous magnetic material and protective film are applied.

しかしながら、下地膜付与後の鏡面加工をＲｕ（平均線
中心粗さ）０．０１０μｍ以下Ｒｍａｘ　（最大粗さ）
０．０７０μｍ以下にする加工を行うと、ヘッドのスラ
イダも銀面加工されているので、両者の摩擦係数が０．
５以十と大六くなり、液体閥清剤や空気中の水分がその
間に入ると強く吸着１７てＬｔう。なお、これ以上大き
い面粗さで、かつヘッドのスライダー長より短い周期の
凸凹を有する面にすると、ヘッドのギャップ部とディス
クの磁性体との距離が変化し出力が変化する。こｆｌは
ノイズを増加させ、信号のイＸｊ相マージンを低下させ
好１しくない。However, mirror finishing after applying the base film is Ru (average line center roughness) of 0.010 μm or less Rmax (maximum roughness)
When processed to 0.070 μm or less, the friction coefficient between the two will be reduced to 0.000 μm since the head slider is also processed to have a silver surface.
5 to 10 and 6, and when liquid clarifying agent or moisture in the air gets between them, it is strongly adsorbed. Note that if the surface has roughness greater than this and has irregularities with a period shorter than the slider length of the head, the distance between the gap portion of the head and the magnetic material of the disk will change, and the output will change. This fl is undesirable because it increases noise and reduces the IXj phase margin of the signal.

〔発明が′Ｎｆ法しようとする問題点〕−］コ述の摩擦
、吸着と出力変化との両者に対して最適な面粗さをつけ
る方法のひとつとして、ヘッドのディスクに対する運動
方向つ捷りディスクの円筒方向に多数の溝をつける方法
が考乏られる。[Problems that the invention attempts to solve with the 'Nf method] -] As one method for achieving optimal surface roughness for both friction, adsorption, and output changes as described above, it is possible to change the direction of movement of the head relative to the disk. There are many ways to create a large number of grooves in the cylindrical direction of the disk.

つ壕り、ヘッドのギャップからディスクを見ると、ギャ
ップの長手方向に凸凹はあるか、ディスクが回転しても
その凸凹の形状は変化しないので、出力変化は生じない
。If you look at the disk from the head gap, are there any unevenness in the longitudinal direction of the gap?The shape of the unevenness does not change even when the disk rotates, so no change in output occurs.

寸だスライダーもディスクに全面に接するわけでなくデ
ィスクの凸部のみで接するため摩擦係数が小さくなり、
四部に液体潤滑膜や水分がた壕るため、凸部（」−の液
体）は、下層部の厚みより薄くなり吸着が生じにくい。The slider also does not come in contact with the entire surface of the disc, but only on the convex part of the disc, so the coefficient of friction is small.
Since the liquid lubricant film and moisture are trapped in the four parts, the convex part (liquid in "-") becomes thinner than the lower layer part, making it difficult for adsorption to occur.

このような同心固状の溝が形成可能であれば好せ［７い
が、加］上２つの問題点がある。まず第１にこの溝をつ
ける加」：の加Ｘｒ、具としては、ラッピングテープ（
有機物テープ上に砥粒を付けたもの）や、ポリシングテ
ーブ（表面に凹部を有する布の中に砥粒を含浸させたも
の）が考えられているが、上り己の加Ｅ−Ａの砥粒とし
てアルミナ、ダイアモンド、炭化ケイ素等を用い、下地
膜を無電、解ニッケル膜にするといずれの砥粒でも、膜
中に砥粒が食い込み、門の溝もできるとともに凸の突起
が生じる。どの突起は、０．１〜１μｍの大きさで、ヘ
ッドの浮上に支障が生じ衝突により膜が剥がれ、ミッシ
ングエラーを生じる亮さになる場合もある。これは無電
解ニラクル膜の延性が大きいだめ、砥粒により、塑性変
形して溝のわきに土手状に盛り上がったり、これが破断
つ捷り切削された場合、切シ粉が連続的に丸く巻かれて
、排出できなかったり］７て凸部が牛じたためである。It would be great if such concentric solid grooves could be formed, but there are two problems. First of all, make this groove. As a tool, use wrapping tape (
(organic tape with abrasive grains attached) and polishing tape (a cloth with recesses on the surface impregnated with abrasive grains) are being considered; If alumina, diamond, silicon carbide, etc. are used as the base film, and the base film is an electroless or nickel film, the abrasive grains will dig into the film, creating gate grooves and convex protrusions. Any protrusion has a size of 0.1 to 1 μm and may interfere with the flying of the head, causing the film to peel off due to collision, resulting in brightness that may cause a missing error. This is due to the high ductility of the electroless Niracle film, which causes plastic deformation due to the abrasive grains, causing it to bulge up like a bank on the side of the groove, and when it breaks and is cut into pieces, the chips are continuously rolled up into circles. [7] This is because the convex part got wet.

それゆえ、無電解ニッケル膜に溝加工を施す場合、その
後テープ、ローラ等によって均す加工や、硬質物で作ら
れたヘッドによって凸部を切り落とす加工が必要となる
が、これによってもなお、本質的に突起部分が多数生じ
ているので、全面を平滑にするのは困難である。Therefore, when grooves are formed on an electroless nickel film, it is necessary to level them with tape, rollers, etc., or to cut off the protrusions with a head made of hard material. Since there are many protruding parts, it is difficult to make the entire surface smooth.

また第２にこの加工は、加工物と被加工物（ディスク）
をディスクの円周方向に相対運動させて傷をつければよ
いが、こうしてできた同心円の溝の中心と、磁気ディス
ク装置に組み入れモータによって回転させたディスクの
中心とは限ずしも一致しないのである。ディスクの内径
と、加工時のスピンドル寸たは磁気ディスク装置のスピ
ンドルとの公差によるガタは、大きい場合１００μｍに
もなる。仮にトラック幅が５０μｍ１溝の中心と回転中
心との芯ずれが５０μｍとするとヘッドのギャップはデ
ィスクが１回転する間に少なくとも２回は溝の同じ列を
跨ぐことに々る。つ壕り、溝の凸凹が大きい場合、例え
ば無電解ニッケル膜を下地膜に用いた場合１周上のある
点を対称に出力変化のうねりが観察され好捷しくない。Secondly, this process requires the processing of the workpiece and the workpiece (disk).
It is possible to scratch the disk by moving it relative to the circumferential direction of the disk, but the center of the concentric grooves created in this way does not necessarily coincide with the center of the disk installed in a magnetic disk drive and rotated by a motor. be. The play caused by the tolerance between the inner diameter of the disk and the spindle size during processing or the spindle of the magnetic disk device can be as large as 100 μm. If the track width is 50 μm and the misalignment between the center of one groove and the center of rotation is 50 μm, the head gap will straddle the same row of grooves at least twice during one rotation of the disk. If the trenches or grooves have large irregularities, for example, when an electroless nickel film is used as the base film, undulations of the output change will be observed symmetrically at a certain point on one circumference, which is not favorable.

一方、陽極酸化膜を下地膜に用いた基板は鏡面加工の１
才、用いられている。なぜなら、陽極酸化膜は膜中の厚
み方向に多数の通電孔が存在するため、その直径が０．
１μｍと微細な凹部に潤滑剤が溜り摩擦係数が小さくな
り、ヘッドの離着陸には支障がないためである。しかし
、発明者が実験したところ、たしかに摩擦係数は０．１
と小さくなるが、湿度を７０チ以上にすると強固な吸着
が生じることがわかった。昨今の小型ディスク装置は必
ずしも空気調整がなされていない一般室において、パソ
コン、ワープロ等に用いられるため、非動作時、つまり
ヘッドとディスクとが接触している時に湿度を限ずしも
好ましい湿度例えば６０％以下に保たれるという保証は
ない。加えて、小型ディスクは軽量化のため、ディスク
回転モーターのトルクも小さく々り吸着した場合容易に
とることけできない。このため、上紀用途のディスクに
おいて寿命保証が困難であることがわかった。On the other hand, a substrate using an anodic oxide film as the base film has a mirror finish.
The talent is being used. This is because the anodic oxide film has many current-carrying holes in the thickness direction of the film, so the diameter is 0.
This is because the lubricant accumulates in the minute recesses of 1 μm, reducing the coefficient of friction and causing no problem for the head to take off and land. However, when the inventor conducted an experiment, the friction coefficient was indeed 0.1.
However, it was found that strong adsorption occurs when the humidity is 70 degrees or higher. Today's small disk drives are used in computers, word processors, etc. in general rooms where air conditioning is not necessarily performed, so when they are not operating, that is, when the head and disk are in contact, the humidity is not limited to the desired humidity, for example. There is no guarantee that it will remain below 60%. In addition, since small disks are lightweight, the torque of the disk rotation motor is also small and cannot be easily removed if the disk is attracted. For this reason, it has been found that it is difficult to guarantee the lifespan of disks for use in the first generation.

以上のように無電解ニッケルメッキ膜では突起とそれに
伴う出力変化が、陽極酸化膜では吸着が各々問題である
ことがわかった。As described above, it has been found that protrusions and associated output changes are a problem with electroless nickel plating films, and adsorption is a problem with anodic oxidation films.

〔問題点を解決するための手段〕[Means for solving problems]

これらの問題点を検討したところ、＠砂酸化膜に、下記
の条件の溝をいれれば、突起が生じず、かつ吸着の生じ
ないディスクとなることが判明した０ 陽極酸化膜は、無電解ニッケルメッキ膜に比べ延性が低
く、脆性破壊が主におこるため、金属のような切削加工
は行われず、切わ粉がダンゴ状になることはない。また
、塑性変形も生じにくく、クラックが入るので切り塵は
極めて排出しやすい。After examining these problems, it was found that if grooves were made in the sand oxide film under the following conditions, a disk with no protrusions and no adhesion could be created. Since it has lower ductility than plated films and mainly suffers from brittle fracture, it cannot be cut like metal, and the chips do not form into lumps. In addition, plastic deformation is less likely to occur, and since cracks occur, it is extremely easy to remove cutting dust.

この膜の性質を用いて、突起を生じず、主に溝のみをつ
けることが可能であるととを見出（〜だ。It was discovered that by using the properties of this film, it is possible to create only grooves without creating protrusions.

また、その溝により、鏡面のスライダー面が湿度９０％
以上で接触させても凝着が生じない■り強固な吸着が生
じ々いことがわかった。In addition, the groove allows the mirror slider surface to withstand humidity up to 90%.
It was found that no adhesion occurred even when the materials were brought into contact with each other in the above manner, and strong adsorption was unlikely to occur.

なお、溝の形状本数等も同心円状の溝を付けて検討した
が、現在多く用いられている接触式の表面粗さ計では、
針の大きさを直径２μｍＪＪ下に小さくするのが困難の
ため溝にはいりにくいので主にＳＥＭ観察により大きさ
を測定した。これによると深さは０．００５μｍ以下で
は、溝を付けていないものに較べ吸着性は有意差がなく
、０．３μｍ以上の場合は、溝の底に付けられた磁性膜
がヘッドの磁場に感じなくＡるので、出力のオーバーラ
イド（重ね書き）特性、およびノイズに好ましく々い。In addition, the shape and number of grooves were also investigated by adding concentric grooves, but with the contact type surface roughness meter that is currently widely used,
Since it is difficult to reduce the size of the needle to less than 2 μm in diameter and it is difficult to fit into the groove, the size was mainly measured by SEM observation. According to this, when the depth is 0.005 μm or less, there is no significant difference in adsorption compared to the one without grooves, and when the depth is 0.3 μm or more, the magnetic film attached to the bottom of the groove is affected by the magnetic field of the head. Since A is not perceptible, it is preferable for output override characteristics and noise.

また、幅を０．１μｍ以下にするのは、砥粒の大きさが
数μｍのために、均一に付けることは困難で、２μｍ以
上にすると、それに伴い深さも大きくなるので、好オし
くない。また、スライダー幅が１００〜８００Ｉ１ｍな
ので本数は少なくとも１０μｍに１本ないと吸着防止に
効果がない。Also, setting the width to 0.1 μm or less is difficult because the size of the abrasive grains is several μm, so it is difficult to apply it uniformly, and setting the width to 2 μm or more is not recommended because the depth will increase accordingly. . Further, since the slider width is 100 to 800 I1m, the number of sliders must be at least one per 10 μm to prevent adsorption.

一方、ディスクの円周方向と交差した溝を持った磁気デ
ィスクを製作して突起、吸着、出力、ノイズ、耐摺動性
、浮上性等を検討したが、陽極酸化膜は本質的に凸部を
生じないので、ノイズは、交差角が大きくなると少し劣
化するものの、その他は交差角０度つまり同心円状の溝
のものと何ら変化がなく、耐摺−１性はそれより良い結
果が得られ、溝の効果は交差角に左右されないことが判
明した。なお、実用上亮記録密度用のｉ＃膜磁気ディス
クとするために、４５度までが好ましい。特に２〜５度
で、摩耗粉が排出され易くなるのか凸の頂点が丸くなる
ためか耐摺動性が良くなる。On the other hand, we fabricated a magnetic disk with grooves that intersected the circumferential direction of the disk and investigated the protrusions, adsorption, output, noise, sliding resistance, floating properties, etc., but the anodic oxide film essentially had no protrusions. Although the noise deteriorates slightly as the crossing angle increases, there is no other difference from that of concentric grooves with a crossing angle of 0 degrees, and better results in sliding resistance can be obtained. , the effect of the grooves was found to be independent of the crossing angle. Incidentally, in order to obtain an i# film magnetic disk for practical use with a high recording density, the angle is preferably up to 45 degrees. In particular, at 2 to 5 degrees, the sliding resistance improves, perhaps because abrasion powder is easily discharged or because the apex of the convexity becomes rounded.

また、この交差溝は、加工物のラッピングテープ、ボリ
シング布をディスク回転運動に加え、ある相対運動させ
れば容易につけられる。例えば、テープの半径方向の揺
動、布の偏心回転等が挙けられる。Further, the intersecting grooves can be easily formed by adding the lapping tape or borising cloth of the workpiece to the rotational movement of the disk and causing a certain relative movement. Examples include radial swinging of the tape, eccentric rotation of the cloth, and the like.

実施例 アルミニウム合金（Ｍｇ４．７％、その他Ｓｔ　＊　Ｆ
ｅ＋Ｃｕ　＋　Ｍｎ等は合計で０．０２％、残部Ａｔ　
）を、外径１５０ｗｑ、内径４０　ｍ　、板厚１９０５
ｍｍの形状に仕上げた後、クロム酸浴により陽極酸化を
施し、１６μｍ厚の陽極酸化膜（アルミナ）の層を形成
した。浴で溶解し、多孔質になっている表層を、平均粒
径０．３μｍのアルミナの砥粒で２μｍ除去し洗浄後、
ホワイトアルミナの砥粒を表面に付けたテープを回転す
る基板に押し付けかつ半径方向に動かして溝をつけた。Example aluminum alloy (Mg4.7%, other St*F
e+Cu+Mn etc. total 0.02%, balance At
), outer diameter 150 wq, inner diameter 40 m, plate thickness 1905
After finishing it into a shape of mm, it was anodized in a chromic acid bath to form a layer of anodic oxide film (alumina) with a thickness of 16 μm. After removing 2 μm of the porous surface layer dissolved in the bath using alumina abrasive grains with an average particle size of 0.3 μm,
A tape with white alumina abrasive grains on its surface was pressed against a rotating substrate and moved radially to create grooves.

その後すみやかに洗浄し、Ｃｏ　−Ｎｉの磁性膜とＣの
保膿潤滑膜とをスパッタで付けた上にフッ化オイル系の
液体潤滑剤をスピンコードで塗布し、磁気ディスクをつ
くった。Thereafter, it was quickly washed, and a Co--Ni magnetic film and a C retentive lubricant film were sputtered on, and a fluorinated oil-based liquid lubricant was applied using a spin cord to produce a magnetic disk.

また比較のため、無電解ニッケルメッキ膜を１５μｍつ
け、あとは同種の加工を施したものを製作した。For comparison, a 15 μm thick electroless nickel plating film was applied and the same type of processing was applied.

また、溝の状態を変化させるため、溝加工のディスク回
転数・砥粒の粒径・テープの半径方向の移動速度をパラ
メータにして、基板の種類を含め１６条件の実験を行な
った。溝の深さは、タリーフ　Ｍ（ランクテーラーホブ
ソン社製）の２μｍの触針で測定し、突起数はＡＥセン
サーを塔載したヘッド（浮上量０．１５μｍ）にて測定
し、片面の個数を数えた。Furthermore, in order to change the condition of the grooves, experiments were conducted under 16 conditions, including the type of substrate, using the number of revolutions of the disk for groove processing, the grain size of the abrasive grains, and the moving speed of the tape in the radial direction as parameters. The depth of the groove was measured with a 2 μm stylus of Tarif M (manufactured by Rank Taylor Hobson), and the number of protrusions was measured with a head equipped with an AE sensor (flying height 0.15 μm). I counted.

評価は、出力のオーバーライド特性、ＣＳＳテストのク
ララシスするまでの回数、吸着性、Ｓ／Ｎ比の４つを行
な込、それぞれＩ　Ｆ　１．２５ＭＨｚ、２Ｆ　２　、
５ＭＨｚで２８　ｄＢ以上、２００００回以上、湿度８
０係、温度４０℃６日間で１０ｇｆ以下、３ｆｌｄＢ以
−ヒという条件で合格とした。結果を表１に示す。The evaluation included output override characteristics, number of CSS tests until clarification, adsorption, and S/N ratio, respectively, at I F 1.25 MHz, 2 F 2 ,
28 dB or more at 5MHz, 20,000 times or more, humidity 8
The test was passed under the conditions of 10 gf or less and 3 fldB or less at a temperature of 40° C. for 6 days. The results are shown in Table 1.

Ａ、Ｂでわかるように無電解ニッケルメッキ膜は、突起
が多いのに対し２陽極酸化膜は突起が殆ど生じない。特
にＡの突起は、ミクシングエラーにつながるものが１２
ケあった。Ａとり、ＢとＦで加工法ｔｇ−を比較したが
６倍、１１倍と無′ｌａ解ニッケルメッキ膜の方が大き
く切削さね易いことがわかっ／こ。As can be seen from A and B, the electroless nickel plating film has many protrusions, whereas the 2-anodized film has almost no protrusions. In particular, there are 12 protrusions in A that lead to mixing errors.
There was. We compared the machining methods tg- for A, B, and F, and found that the la-free nickel plating film was easier to cut by 6 times and 11 times.

ＡとＤの表面を観、察り、たところメッキ膜は溝のわき
に土手が生じているが、陽極酸化膜は溝がきれいにひか
れていることがわかる。陽極酸化膜の溝内は、微小なり
ラックによる剪断破断面になっていることがわかった。Observing and observing the surfaces of A and D, it can be seen that the plating film has banks at the sides of the grooves, but the anodized film has neat grooves. It was found that the inside of the groove of the anodic oxide film had a shear fracture surface due to minute racks.

壕だ、溝が深くなるとオーバーライド特性が悪化１７、
溝が浅いと吸着性が悪化することがわかる。It's a trench, the deeper the trench, the worse the override characteristics17.
It can be seen that the shallower the groove, the worse the adsorption performance.

また、Ｃ８Ｓ特性は溝が深くなるとそれに伴う突起部の
頂点が摩耗し膜が剥がれ、一部ミツシングエラーを生じ
るため、クラッシュはしないが好ましくないことがわか
った。丑た０のように交差角を４５度近くにするとＳ／
Ｎ比は２８　ｄＢと好捷しく第　　　　１　　　　表 合格＜２８ｄＢ、＜２０に回、＞１０ｇｆ、＜３０ｄＢ
・　Ｉ　Ｉ　・ ないことがわかった０ 〔発明の効果〕 本発明の磁気ディスクを有する磁気ディスク装置は、出
力特性と、Ｃ８Ｓ吸着相性とをあわせ満足するものであ
り、長寿命を保証することができ・１２・ 昭和６１年　特許願　第３４２０２号 発明の名称　磁気ディスク 補正をする者 小作どの関係　　特許出願人 イ１所　東京都千代Ｆ１１１７丸の内７−丁１１番２号
名称　（５０８）日立金属株式会ネ１ 補正の対象　明細書の１−発明の詳細な説明」の欄。In addition, it was found that the C8S characteristic is undesirable because as the groove becomes deeper, the apexes of the protrusions are abraded and the film peels off, causing some cutting errors, although no crashes occur. If the intersection angle is close to 45 degrees like Ushita 0, S/
The N ratio was excellent at 28 dB. Table 1 passed <28 dB, <20 times, >10 gf, <30 dB.
・I I Deki・12・1986 Patent Application No. 34202 Name of the invention Relationship between the person who performs magnetic disk correction and tenancy Patent applicant I 1 No. 11-2, 7-chome, Marunouchi, F1117 Chiyo, Tokyo Name (508) Hitachi Metals, Ltd. 1. Subject of amendment 1-Detailed description of the invention" column of the specification.

補正の内容　別紙の通り 補正の内容 １．第２頁第１８行のｒＲｃ＋、１をｒＲａ　Ｊに訂正
する。Contents of the amendment Contents of the amendment 1. Correct rRc+, 1 on page 2, line 18 to rRa J.

２、同頁第１９行の１平均線中心粗さ１を１中心線平均
粗さ」に訂正する。2. Correct 1 average line center roughness 1 in line 19 of the same page to 1 center line average roughness.

３、第３頁第１６行の「あるか、」を「あるが、」に訂
正する。3. On page 3, line 16, ``Aruuka'' is corrected to ``Aruga,''.

４、第５頁第３行の１均す」を「凸部をつぶす」に訂正
する。4. In the 3rd line of page 5, ``1 equalize'' is corrected to ``crush the convex part''.

５、第１０頁第１２〜１３行の「タリ　−フ　Ｍ」を１
タリサ一フ５Ｍｊに訂正でる。5. ``Tarif M'' on page 10, lines 12-13
Tarisafu 5Mj is corrected.

１ズ十1zu ten

Claims (1)

【特許請求の範囲】[Claims] アルミニウムまたはアルミニウム合金基板上に陽極酸化
膜、その上に薄膜磁性膜を持つ磁気ディスクにおいて、
陽極酸化膜上にディスク円板中心と同心の円と０度ない
し４５度の角度で交差し、かつ幅０．１μｍないし２μ
ｍ、深さ０．００５μｍないし０．３μｍの溝を、磁気
ヘッドのスライダーの動く領域に、１０μｍに少なくと
も１本付けたことを特徴とする磁気ディスク。In a magnetic disk that has an anodized film on an aluminum or aluminum alloy substrate and a thin magnetic film on top of it,
On the anodic oxide film, intersect a circle concentric with the center of the disk at an angle of 0 to 45 degrees, and have a width of 0.1 μm to 2 μm.
1. A magnetic disk characterized in that at least one groove having a depth of 0.005 μm to 0.3 μm is formed every 10 μm in an area in which a slider of a magnetic head moves.