JPS62197917A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a titled medium which has excellent wear resistance and has excellent slipperiness with a head by forming a protective film of discontinuous films consisting of a hard material on a magnetic film formed on a nonmagnetic substrate and a soft material disposed on the discontinuous parts thereof. CONSTITUTION:The composite film consisting of the soft material 4 and hard material 5 is used as the protective film. The composite film refers not to the laminated film consisting of the hard material 5 and the soft material 4 but to the case in which the part of the hard material 5 and the part of the soft material 4 are alternated in the intra-surface direction; for example, to such a case in which the spacing between the part of the network-like hard material 5 is filled with the soft material 4. A material having >=1,000kg/mm<2> Vickers hardness is preferable as the hard material 5. Any material which has the hardness value smaller than the hardness value of the hard material 5 to be combined is usable as the soft material 4.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in magnetic recording media.

[Problem that the invention seeks to solve]

BACKGROUND ART In order to achieve higher recording density than ever before, research and development on using continuous magnetic films in magnetic recording media has been progressing. These magnetic recording media are polymer films.

F on a substrate made of non-magnetic material such as aluminum or glass.
Vacuum deposition, sputtering, ion blasting, electroplating, and chemical plating are used to deposit thin films of magnetic materials mainly made of ferromagnetic metals such as e, Go, and Ni, or alloys and compounds containing these elements as main components. It is manufactured by forming it with etc. If a recording/reproducing head is brought into direct contact with the surface of this magnetic film, there is a problem in that the surface of the magnetic film is easily worn and the head is easily damaged.

As a means to solve this problem, 5i is applied to the surface of the magnetic film.
ns, AQxOs, S i C, T i C, etc.
04602, JP-A-58-130437), or A u.

Method of forming a metal film such as Pt, Rh, Pd, AQ, etc. as a protective layer (JP-A-53-40505; JP-A-57-17
6537) etc. have been proposed.

[Problem that the invention seeks to solve].

According to experiments conducted by the inventors, metal-based protective films do not have sufficient wear resistance, and compound-based hard materials are brittle and weak against impact forces, and can easily damage the head. It turns out that there is a point.

The present invention has been made in view of these problems,
The purpose is to improve the wear resistance of the protective film and the slipperiness of the head.

[Means for solving problems]

The protective film must have corrosion resistance to protect the magnetic film, as well as wear resistance, lubricity to the magnetic head, and a liquid lubricant to ensure lubricity. In order to further improve the properties, the film thickness must be as small as possible (2000 Å or less, preferably 100 Å or less, to prevent deterioration of electromagnetic conversion characteristics.
0 Å or less).

A Q zOs, 5ift, Zr0z, Ties
oxides such as SiC, BaC, TiC, WC, Zr
Carbides such as C, 5iaNa, T i N, Z
All nitrides such as rN are extremely hard materials,
High wear resistance.

However, there are problems with the head being worn out and being weak against impact forces. On the other hand, Sn, Pd*Sb, Bi,
In, Au, Ag, Pt, AQ.

Since metals such as Zn and Cu are soft, they do not damage the head and are weak against impact forces, but they do not have sufficient wear resistance.

ZnS, 5bzSa, CrS, No2
s.

Compound materials such as Zn5e, CdSe, BN, stearic acid, and polymeric materials are also soft materials and have properties similar to those of the metals mentioned above.According to experiments by the present inventors, the difference between soft and hard materials is It has been revealed that by using a composite film consisting of both as a protective film, the advantages of both are combined, and the film exhibits extremely excellent properties as a protective film. A composite film here is not a laminated film of hard and soft materials, but refers to a film in which hard material parts and soft material parts alternate in the in-plane direction when the film is viewed from above. , for example, shows a case where a part of a network-like hard material is filled with a soft material.

As a hard material, Vickers hardness is 1000 kg/am
"Materials with a hardness value of less than this value are preferred; if the hardness value is less than this value, it becomes difficult to obtain sufficient wear resistance. An example of such a material has already been shown, but many other materials can be used. The material may be any material as long as it has a hardness value smaller than that of the hard material to be combined, but it is preferable that the difference in hardness value between the two is 100 kg/mm2 or more, more preferably 300 kg/mm2 or more. Preferably, both the hard and soft materials are non-magnetic materials.

The ratio of the hard material in the protective film, that is, the area ratio when looking at the film from above, is preferably in the range of 10 to 90%.
This ratio is sufficient as long as the practical part of the protective film is within this range.In other words, even if there is a layer of only soft material on the top of the protective film, the soft material part will quickly wear out, so the layer below it will be It is sufficient that the portion that practically functions as a protective film has the above-mentioned ratio.

The film JO of the protective film preferably ranges from 50 to 2000 people, more preferably from 100 to 1000 people.

A film having such a structure can be realized, for example, based on the following principle.

That is, when a film is formed on a substrate by a vacuum evaporation method or a sputtering method, a discontinuous film having a so-called island structure is first formed in the initial stage of film formation. The size of the island varies depending on the formation conditions such as the type of substrate, film material, and substrate temperature, but it ranges from about 20 to 10 μm, and this can be arbitrarily controlled by appropriately selecting the formation conditions. . If a different material is deposited at the stage where a discontinuous film having an island-like structure is formed, that material will adhere to the exposed portions of the substrate. By removing the different materials attached to the tops of the island-like portions by means such as polishing, it is possible to form a composite film in which the isolated islands and the portions filling in between are made of different materials. If one of the materials is selected from hard materials and the other from soft materials, the desired protective film can be obtained. However, the method for forming a composite film is not limited to the case where the above-mentioned thin film growth and development is applied; for example, methods such as photoetching and mask vapor deposition, which are widely used in the semiconductor industry, may also be used.

[Effect]

The protective film of the present invention has excellent wear resistance and lubricity with respect to the head.

[Embodiments of the invention]

Hereinafter, the present invention will be explained by examples.

Example 1 A magnetic recording medium was manufactured using a polyimide film as a substrate by vapor deposition and sputtering in the order shown in FIG. was heated to 200° C. to form a Ge base layer (2) of 300 layers, and then a magnetic film (3) of Go- and 23 wt % C7 was vacuum-deposited to a thickness of 2000 layers. Then, the substrate temperature was lowered to around room temperature, and a small amount of 5n(4) was vapor-deposited. At this time, Sn is M as shown in FIG. 1(b).
It became an island-like discontinuous film with 200 to 300 people and a height of 100 to 300 people. Then, the sample was transferred to a sputtering device and A
The structure shown in C) was obtained by forming nzOa(5) in an I×10-” TorrAr atmosphere with a high frequency output of 4 w/ai and a substrate temperature of 100°C to obtain a structure shown in C). As shown in d), a protective film made of Sn ji'A Q zOa and having a film thickness of 200 was realized by flattening as shown in d). Here, the soft material is Sn and the hard material is A Q zOδ.

In addition, as comparison samples, a magnetic recording medium with no protective film provided at all, a magnetic recording medium with a continuous protective film made only of Sn with a thickness of 200 mm formed by vapor deposition, and a magnetic recording medium with a continuous protective film formed only of Sn with a thickness of 200 mm formed by sputtering method. A magnetic recording medium provided with a continuous N film consisting only of ZOS was prepared.

Using a similar method, Pb and In were used as soft materials.

Sb, Bi, Au, Ag, Cu, Pt, A (1°Zn,
Cd, Rh as hard materials, 5ift, Zr0z.

Tilt, S i C, BaC, T i C, WC,
ZrC.

5isN4. TiN, ZrN, B, S
A magnetic recording medium having a protective film made of a composite film made of a combination of each soft material and a hard material was fabricated using i. In this case, film formation conditions such as substrate temperature and evaporation rate are adjusted for each case, and Sn and A Q
Dimensions similar to those obtained for the combination of °C! Care was taken to obtain a structured composite membrane.

These samples were subjected to a sliding resistance test using the following head. In the sliding test, a disk sample was cut out from each sample, coated with liquid lubricant, and set in a disk rotating device.The disk was then continuously rotated at a speed of 2 m/s by contacting with a head with a load of 16 g. The number of rotations until the magnetic recording medium or head was scratched and no output was produced was measured. The results are summarized in Table 1.

The number of revolutions when no protective film is provided is 1.2 x 10M, and 2 x 10' to 5 x 10 when a protective film of 10M is provided.
It was revealed that the sliding resistance was significantly improved to 5 x 10B to I x 10' times when the protective film made of the composite film of the present invention was provided, whereas the sliding resistance was 11 times.

The Vickers hardness (kglon'') of the hard and soft materials used in the examples is shown below.

AQOa 1850 S i Ox 1200ZrOz
1300 T i Oz 1075SiC2560 B4C2450 TiC2300 WC2200 ZrC2600 SiaNa 2050 TiN 1730 7, r N 1670B
3300 Si 1200 S n 6 1Pb
38In
9Sb 2
94Bi 94Au
190 peopleg
210 Cu 98 Pt 420 AQ 150 Zn 250 Cd 200 Rh 950 Example 2 A protective film consisting of a composite film was formed on the Co-NiIII film formed on the Aα substrate by the following procedure.

As shown in FIG. 2(a), a mist of low vapor pressure oil was applied to the surface of the magnetic film. Next, this sample was attached to a sputtering device and a SiC film of 500 λ was formed by sputtering, and then taken out and chemically treated with an organic solvent etc. to achieve the state shown in b). A polyimide film of 50% was applied to this again by sputtering.
A protective film made of a composite film as shown in (c) was formed by forming the film to a thickness of 0.05 cm and flattening the protrusions by lapping the protrusions.

Ride, stearic acid, Z n S, 5bzSs
, Cr5z.

A composite protective film made of a combination of various materials was formed using MO2S, Zn5e, CdSe, and BN, as in Example 1.

As a result of examining the sliding resistance of these samples using the same evaluation method as in Example 1, it was found that all of them had a sliding resistance of 108 times or more, and were extremely excellent as protective films.

In addition, when the thickness of the protective film was changed in both Examples 1 and 2, it was observed that the sliding resistance tended to improve as the thickness increased, but as the distance between the magnetic film and the head increased, the electromagnetic conversion characteristics has deteriorated. It has been found that the protective film preferably has a range of 50 to 2,000 people, and more preferably a range of 100 to 1,000 people.

In addition, in the present invention, 15 types of hard materials and 23 types of soft materials are given as examples, but the types of materials are not limited to the above.

In addition, in this example, vacuum evaporation method and sputtering method are used as methods for forming the protective film, but the method is not limited to these methods. Any general film forming method such as a spraying method or a coating method may be used.

〔Effect of the invention〕

As described below, the protective film of the present invention has excellent abrasion resistance and lubricity with respect to the head, and is useful for extending the life of the magnetic recording medium.

In the protective film of the present invention, the hard material mainly contributes to improving wear resistance, and the soft material is considered to have the effect of weakening the impact force between the head and the protective film and preventing damage to the head side.

[Brief explanation of drawings]

be.

Claims (1)

[Claims] 1. A magnetic film formed on a non-magnetic substrate has a discontinuous film made of a hard material and a protective film made of a soft material disposed in the discontinuous portion. magnetic recording media. 2. The magnetic recording medium according to claim 1, wherein the area of the discontinuous film of the hard material is in the range of 10 to 90% of the area of the protective film. 3. The above hard material has a Vickers hardness of 1000 kg/mm.
The magnetic recording medium according to claim 1, which is a material having a hardness value of ^2 or more.