JPS60236116A - Magnetic disk and its production - Google Patents

Abstract

PURPOSE:To obtain an excellent magnetic disk having high hardness, corrosion resistance, and a heat resistant substrate by coating, drying and baking of an org. metallic compd., etc. on the surface of a base material consisting of sintered pulverous powder of Al2O3, etc. to form a thin continuous film and providing successively a magnetic film, protective film or lubricating film on the thin continuous film. CONSTITUTION:Pulverous powder of Al2O3, SiO2, MgO, TiO2, TiC, etc. and a binder as water of alcohol are cast into a mold and are sintered under the pressure, by which the base material 1 for the disk is manufactured. The org. metal 2 as expressed by Si(OR)4, M(OR)n, where M is Al, Ti, Fe, Cr, etc. and R is alkyl, is spin-coated on the surface of the material 1. The coating is heated in air or gaseous N2 to form the thin continuous film 3 consisting of metallic oxide or nitride, by which the smooth and dense film having high hardness is obtd. A magnetic layer 4 is formed on the film 3 without the need for a polishing stage and if necessary, the protective film and lubricating film 5 are successively formed thereon. The disk having the excellent magnetic characteristic, heat resistance, corrosion resistance, etc. and excellent durability is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic disk used in a magnetic disk device and a method for manufacturing the same.

(Prior Art) The conditions imposed on magnetic disks include that the magnetic film has a predetermined thickness and excellent magnetic properties, as well as reliability and low cost. In particular, reliability and low cost are largely due to the substrate that forms the base of the magnetic film.
If the flying height I of the magnetic head is reduced along with the recording density, problems such as radocracy are likely to occur, so its reliability depends on the hardness of the substrate and the aiming plane I.

Conventionally, aluminum alloys,
N plated with nickel and phosphorus alloy on aluminum alloy
4P substrates have been used. There are also some experimental cases where ceramics are used as substrates, but they are rarely used. K (as a gas film) on these substrates'
Coated discs coated with -Pe, ;Oj microacicular particles together with adhesive, plated discs plated with Co-N1-P alloy, and sputtered discs with -Fe;O) sputtered films. Disks have been used.

(Problems with conventional technology) However, aluminum alloy substrates lack hardness;
The finishing precision of the mating surface is not sufficient and is expensive, and although the ceramic substrate has sufficient hardness, it is porous and has poor surface properties.

These shortcomings limit the guarantee of reliability as a hunting disc, and furthermore make it difficult to achieve long-term reliability and low cost.

(Objective of the Invention) An object of the present invention is to propose a new magnetic disk that is low in cost and highly reliable, which eliminates the drawbacks of conventional magnetic disks, and a method for manufacturing the same.

(Structure of the Invention) The present invention includes a base material made of a sintered body of fine powder, a first continuous thin film formed on the surface of the base material, a magnetic film serving as a recording medium on the continuous thin film, and the like. In contrast, the magnetic disk is composed of a second continuous thin film, which is a protective film or a lubricating film.The manufacturing method for such a magnetic disk involves high-temperature sintering of fine powder into the shape of a magnetic disk substrate. a step of making a sintered body, and a first step on the surface of the sintered body;
a step of forming a continuous thin film, and a step of forming a magnetic film serving as a recording medium on the first continuous thin film, and
Furthermore, a second protective film or a lubricating film is added to the magnetic film.
The method is characterized by comprising a step of forming a continuous film.

(Detailed Description of Configuration) This invention will be described in detail below with reference to the drawings. 1st
The figure shows the manufacturing process of the disk substrate, which is the first half of the manufacturing process of the magnetic disk of the present invention.
203.5i02. MgQ TiO2, TiQSiQ
This shows the process of pouring Si and other fine powders and a caking agent such as water and alcohol into a mold that takes the shape of a magnetic disk substrate.The mold is flat and has waviness within standard values. Use a degree. Next, FIG. 1(b) shows a sintered body obtained by sintering under pressure. The sintering temperature and time are appropriately selected depending on the composition and particle size of the fine powder used. A sintered disk plate is used as the base material 1,
On top of this, organic metal 2 is spin-coated. (Figure 1 (c)
. ) An example of an organic metal used here is Si(O
R) 4°R is preferably one in which an alkyl group is dispersed with an organic agent such as alcohol.

By heat-treating this in air, oxygen, or nitrogen (as shown in the same figure), a first continuous thin film 3 is formed in the form of metal oxide or metal nitride, forming a first continuous thin film 3 of the base material 1. An extremely smooth, dense and highly hard film can be obtained on the surface.

This eliminates the need for a polishing process, which was essential for conventional disk substrates.

FIG. 2 shows the latter half of the manufacturing process of the magnetic disk of the present invention, in which the magnetic disk substrate shown in FIG.
b)) A magnetic film 4 which will become a recording medium is formed thereon (FIG. 2(b)). This magnetic film may be formed using any known technique. That is, oblique iron oxide fine particles, acicular magnetic metal fine particles, hexagonal plate-shaped barium ferrite fine particles, etc. are polished with an abrasive (Al2
A method of adding a resin binder dispersant together with fine particles of O2 or 5J02 and drying and curing after spin coating, a method of forming a metal magnetic film by vapor deposition, sputtering, or plating, and a method of forming an iron oxide film by vapor deposition or sputtering. An example is the method. Since the magnetic disk substrate is flat with small surface roughness and no holes, the reproducibility of the magnetic properties of the magnetic film 4 is good (particularly when vapor deposition, sputtering, or plating is used, the presence or absence of holes affects the characteristics. The uniformity of the film thickness was also equal to or better than that of aluminum alloy plated with amorphous NiP. When the flying height of the magnetic disk is a little large (0.4 .mu.m or more), it can be used as it is as a magnetic disk (2).

If the flying height is small, a lubricant film 5 may be further applied as shown in FIG.

Alternatively, as shown in FIG. 2), a protective film 6 is further formed on the magnetic disk and used as a magnetic disk 0. One method for forming the protective film 6 is a method similar to the process shown in FIG. This is a method of forming a continuous thin film (second continuous thin film) 6. Here, the second continuous thin film 6L does not necessarily have to have the same composition as the first continuous thin film. Furthermore, 5iOz and AJzO are used as a protective film.
Materials such as ζC are deposited by vapor deposition, sputtering, and plasma CVD.
It may be formed by a method. Also, since this protective film was too flat, it was removed by puff polishing in the circumferential direction.
By forming a striped pattern of fine irregularities of 0OA' (formation of the striped protective film 7), the magnetic disk 0 has improved wear characteristics with the magnetic head (the time required to reach definitive damage is more than doubled). is completed. (FIG. 2 (e).) If a lower flying height is required, a lubricant film 5 is formed on the magnetic disk ◎ by step (f) to form a magnetic disk ■. As the lubricating film 5, YYDAX or Kr(Y'l"O
X (both are DuPont product names) can be used (
Figure 2(f)).

In order to accurately detect servo information, it is desirable that the data transducer and the servo transducer be separated in the radial direction in one magnetic head sifter. It is necessary that there be no difference in thermal expansion of the base material 1. The thermal expansion coefficients of the base material 1 and the slider are α and β, respectively, the distance between the data transducer and the servo transducer is 1, and the allowable positioning error of the data transducer is ΔW. If 11(α-β)11≦α·ΔW(1), then the thermal expansion of the magnetic disk plate and the expansion/contraction positional deviation due to heat of the data transducer fall within the allowable range.

(@Example) Fine powder was kneaded with an aqueous polyvinyl alcohol solution as a binding agent, poured into a mold for a disk substrate,
High-temperature sintering was performed at 1,600° C. while pressurizing at a pressure of 0 to 3,000 degrees centigrade to produce a base material consisting of a disk-shaped fine powder sintered body. The surface of the mold was polished in advance so that the area was less than 100OA', so the area of this base material was 100OA' or less.
A' It hit me. Organometallic Si (O
H) Apply the ethyl alcohol solution of J and apply 1
It was dried while rotating at 00 to 1000 γh to form a substantially uniform organometallic film over the entire surface. Next, the base material with the organometallic film was heat-treated in air at 200 to 400°C to form a continuous thin film (first continuous thin film) of 5102, which is the organometallic oxide. The 5i02 film thus produced was dense, hard, and extremely smooth with a surface roughness of less than u50A'. On this first continuous thin film, a Cγ film was deposited at 400 OA as a magnetic film to serve as a recording medium.
' After sputtering, the Co-N t -Cr alloy film was
80 Formed by sputtering method. This is sufficient for a magnetic disk, but in order to increase reliability, a 5i02 film with a thickness of 100 OA was formed as a second continuous thin film on top of it using the same method as the first continuous thin film. . Next, the surface of this second continuous thin film was subjected to puff polishing for 1 minute to form a striped pattern of fine irregularities of about 50 A0. A well-known lubricant was applied to the surface of the magnetic disk produced in this way, and a durability test was conducted, and reliability for more than 5 years was guaranteed. Note that C (carbon) was formed by sputtering instead of 5i02 as the second continuous thin film (
A material with a thickness of about 500A0) is also suitable. Puff polishing for 1 minute was the same, but no lubricant was needed.

(Effects of the Invention) If the manufacturing method of the present invention is used as a magnetic disk plate, which is the basis for guaranteeing the reliability of magnetic disks, a large number of substrates can be made from one mold, and they can be made flat and flat without the need for the labor-intensive process of polishing. Since a dense substrate with sufficient hardness can be obtained with good reproducibility, mass production is possible at low cost.

The magnetic disk substrate is dense, highly hard, and made of ceramics, so there are no problems with corrosion resistance or heat resistance, making it highly reliable.
Due to its high heat resistance, it is possible to use any method for manufacturing magnetic films that will become magnetic media, resulting in the advantage that magnetic media with desired magnetic properties can be obtained.

The magnetic TiSF substrate shown in the example is the same as a typical toslider material for a thin film magnetic head in which two transducers, a theta transducer and a servo transducer, are arranged in parallel on one slider. Therefore, it is possible to set the thermal expansion coefficients to be approximately the same, and the relationship of the above equation ( ) can be fully satisfied, so the detection of servo information is extremely accurate. Become. As a result, it is possible to further increase the track density.

No. For this reason, a large number of materials can now be used as protective films or lubricants.

It should be noted that the above-mentioned embodiment is only an example of the present invention, and it goes without saying that all the above-mentioned advantages will be exhibited if the gist of the present invention is implemented.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the process of making a magnetic disk substrate which is the basis of the present invention, and Fig. 2 is a diagram showing the process of making a magnetic disk substrate of the present invention. ...Organic metal film 3...First continuous film 4...Magnetic film 5...Lubricant film 6... ...Protective film (second continuous thin film) 7...
......It is a protective film with a striped pattern. (12) 71 Figure

Claims (1)

[Claims] (11) Consisting of a base material made of a sintered body of fine powder, a first continuous thin film formed on the surface of the base material, and a magnetic film forming a recording medium formed on the continuous thin film. A magnetic disk characterized by: (2) a base material made of a sintered body of fine powder, a first continuous thin film formed on the surface of the base material, and a magnetic film forming a recording medium formed on the continuous thin film. and a second continuous thin film, which is a protective film or a lubricating film. (3) The surface of the protective film is provided with fine irregularities in the circumferential direction. A magnetic disk according to scope 2. (4) A step of making a sintered body of fine powder, a step of forming a first continuous thin film on the surface of the sintered body, and a step of recording on the first continuous thin film. A method for manufacturing a magnetic disk, comprising: a step of forming a magnetic film to serve as a medium. forming a magnetic film to serve as a recording medium on the first continuous thin film; and forming a second continuous thin film as a protective film on the magnetic film. A method of manufacturing magnetic disks.