JPH01319121A - Thin film magnetic disk - Google Patents

Abstract

PURPOSE:To hardly generate a head clash, etc., by dispersing fine spherical ceramic particles having a specific grain size nearly uniformly onto a substrate and forming at least a ferromagnetic metallic film and thin film of a protective layer thereon. CONSTITUTION:The thin film magnetic disk 1 is completed by dispersing the fine spherical ceramic particles 3 which are nearly truly spherical and have the grain size ranging 100-1000Angstrom are nearly uniformly dispersed on the substrate 2 for the thin film magnetic disk and forming the thin films of an underlying metallic layer 4, the ferromagnetic metallic film 5, the protective layer 6, a lubricating layer 7, etc. Fine silica particles are used by dispersing the same in an aq. soln. and filtering away coarse particles therefrom at need in case of using said particles as the fine spherical ceramic particles 3. The surface roughness of the disk 1 is, therefore, uniformized and the coefft. of dynamic friction is consequently lowered. The sticking and clash between the disk and the magnetic disk are hardly generated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thin-film magnetic disk suitable as a recording medium, and in particular to a thin-film magnetic disk with improved manufacturing pretreatment. Regarding the air disc.

[Prior art and problems to be solved by the invention] In the technology of manufacturing magnetic tape, which is a type of magnetic recording medium, fine particles such as polymer latex particles are dispersed in a binder.
For example, Japanese Patent Laid-Open No. 1983-1984 discloses a manufacturing method and technical content of spin-cording on a chip base, forming a magnetic layer thereon, and forming protrusions on the surface to improve still resistance properties.
It is introduced in JP-A-94227, JP-A-59-92428, JP-A-61-8720, etc. Also,
There is also a method of coating and dispersing polymer latex particles without using a binder, and this method is described, for example, in JP-A-61-9822.
It is disclosed in the publication number etc.

However, the thin film forming method using sputtering involves dispersing fine particles in a binder and forming them on a substrate, which is not preferable because the substrate is heated in a vacuum, ion etching, etc. Also, polymer latex particles also have hardness and There was a problem that heat resistance was insufficient.

[Means to solve the problem]

The thin-film magnetic disk of the present invention has a grain size of 1 on a non-magnetic substrate.
The above-mentioned problems were solved by dispersing almost uniformly spherical ceramic fine particles of 0.08 to 1000 particles and forming at least a ferromagnetic metal film and a thin protective layer thereon.

〔Example〕

Hereinafter, a specific example will be described with reference to FIG. FIG. 1 is a sectional view of an embodiment of a thin film magnetic disk according to the present invention. As shown in this figure, on a substrate 2 for a thin film magnetic disk, grains with a diameter of 100 to 1
000^ of spherical ceramic fine particles 3 are dispersed almost uniformly, and a base metal layer 41 ferromagnetic metal WA5.
Protective layer 6. Thin films such as the lubricating layer 7 are formed to complete the thin film magnetic disk 1.

When using, for example, silica fine particles as the spherical ceramic fine particles, it is preferable to disperse an aqueous solution of silica fine particles (for example, Snowtex, Kaguchi Kagaku Kogyo Co., Ltd.) into the aqueous solution, and if necessary, remove coarse particles by filtration before use.

When adsorbing and dispersing on the magnetic disk substrate 2, a method such as a spin cord, dipping, pulling, and spin drying is used. The density of the spherical ceramic fine particles 3 to be adsorbed is 10
If it is less than 10,000 pieces/d, no improvement in durability can be expected;
- or above, it adversely affects the formation of a thin film and causes deterioration in magnetic recording characteristics.

In addition, since the adhesion of the thin film also decreases, the number of 200,000 to 300,000 pieces/- is appropriate. Note that the surface shape to be dispersed does not need to be specified.

Further, the particle size of the spherical ceramic fine particles 3 used is 100
If the particle size is smaller than 8, there is no effect, and if it is larger than 1,000 particles, the flying height of the magnetic head will be exceeded, and experimental results have shown that it will cause a head crash.

<Example 1> On a polished A4 substrate 2 coated with electroless N1PlJ gold (plated), 200,000 to 300,000 µm of silica particles were deposited.
! The sample was immersed in a 10% aqueous solution so as to have a density of /-, and after being pulled up, it was spin-dried while rinsing with water to form 1000 granular protrusions. Next, a Cr underlayer 4 is formed on this substrate 2 by sputtering.
Co-Ni-Cr alloy5. 600, 500, and 400 layers of carbon-protected WA6 were formed, respectively.

<Example 2> The A1 substrate 2 used in Example 1 was textured with a polishing tape having a white alumina particle size of 5 μm. This substrate was rubbed with a cloth tape impregnated with a 10% aqueous solution of silica sol to adsorb the silica fine particles 3 onto the substrate 2, which was then rinsed with water and spin-dried.

On this substrate 2, metal thin films [4, 5] were formed by sputtering in the same manner as in Example 1.

As a comparative example, a metal thin film 4.5 was formed by sputtering on the substrate 2 prepared by the method of Example 1.2 without adsorbing the silica fine particles 3, and each was coated with a fluorine-based lubricant 7.
After applying C85fContactstart 5tOI, the initial friction coefficient was measured for each disc.
)) Tests were conducted. The results are shown in Table 1.

From Table 1, it can be seen that the thin film magnetic disk of the present invention has a smaller dynamic traction coefficient than the conventional example (comparative example), and as a result, the service life is significantly increased. The reason for this is thought to be that the surface roughness of the disk became uniform because the spherical ceramic fine particles 3 such as silica fine particles having the same particle diameter of 100 to 1000 particles close to perfect spheres were almost uniformly dispersed.

(Table 1) (Note: In Table 1, "Example 1", "Comparison 2", etc. refer to Example 1 and Comparative Example 2, respectively. In addition, ◎ indicates that there was no sticking or sticking even after 30,000 tests. (X means that no head crash occurred, and X indicates that sticking occurred and the number of times at that point.) [Effect] Since the thin film magnetic disk of the present invention is manufactured as described above, the disk The surface roughness can be made uniform, so the dynamic I
It has excellent features such as a smaller II friction coefficient, less chance of crashes due to sticking between the disk and the magnetic head, significantly increased lifespan, and significantly improved reliability.

[Brief explanation of the drawing]

FIG. 1 shows the thin Mli! of the present invention! 1 is a cross-sectional view of one embodiment of an air disk; FIG. DESCRIPTION OF SYMBOLS 1... Thin film magnetic disk, 2... Substrate, 3... Spherical ceramic (silica) fine particles, 4... Base metal layer,
5... Ferromagnetic metal film, 6... Protective layer, 7... Lubricating layer. Patent applicant: Japan Victor Co., Ltd. Representative: Japanese Figure 11 Procedural amendment 1, Indication of the case Patent application No. 151930 of 1988 2, Name of the invention Thin film magnetic disk 3, Person making the amendment Relationship to the case Patent application Address: 3-12 Moriya-cho, Kamisatsuyo-ku, Yokohama, Kanagawa Prefecture The contact area between the disk and the magnetic head has decreased.'' (2) Correct j on page 6, line 17 of the same document to ``and the contact area between the disk and the magnetic head decreases''.

Claims (1)

[Claims] A thin film characterized in that it is created by substantially uniformly dispersing spherical ceramic fine particles having the same particle size of 100 Å to 1000 Å on a non-magnetic substrate, and forming at least a ferromagnetic metal film and a protective layer thin film thereon. magnetic disk.