JPS60251518A - Magnetic storage medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic storage medium having excellent resistance to wear, moisture, etc. and good durability by coating the cured film contg. colloidal silica having a grain size within a specific range and alkoxide or metallic chelate compd. of a specific metal on a thin magnetic metallic film. CONSTITUTION:The coating liquid prepd. by dissolving 50-95wt% the colloidal silica having 1-80 millimicrons and 5-50wt% the metallic alkoxide or metallic chelate compd. of the element selected from the groups IV and V of periodic table into a solvent mixture composed of isopropanol and normal butanol is prepd. Such coating liquid is coated on the thin magnetic metallic film consisting of a Co-Ni-P alloy, etc. and provided on the Ni-P alloy-plated surface of a substrate such as an Al disk finished to a specular surface and is subjected to a heating treatment to form the cured coating film condensation-polymerized with the colloidal silica and the metallic alkoxide or metallic chelate compd. The magnetic storage medium having the remarkably improved moisture resistance and durability is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a magnetic storage body used in a magnetic recording device (magnetic disk device, magnetic drum device, etc.), and more specifically, to a magnetic storage medium used in a magnetic recording device (magnetic disk device, magnetic drum device, etc.). -Relating to hardening of.

[Prior art]

In magnetic storage devices, scratches often occur on thin metal magnetic media due to contact friction between a magnetic storage body and a recording/reproducing head (hereinafter referred to as a head) during recording and reproduction. Furthermore, the thin metal magnetic medium often rusts or peels due to moisture, causing it to lose its function. In order to protect the head and the magnetic memory from such contact friction, abrasion, and collision between the head and the magnetic memory, it is necessary to completely coat the thin metal magnetic medium of the magnetic memory.

Conventionally, metal-plated waists (for example, C!r,
Rh, N1-P, etc.), a method of oxidizing a metal magnetic thin film, and a method of coating an oxide film after the oxidation, etc. It was not an effective method for To improve all of the above deficiencies: A proposal to use a polysilicate film made from tetraalkoxysilane as a protective film (Japanese Patent Publication No. 57-5
8731) Proposal of using a hydrolyzed polymer of metal alkoxide or tetraalkoxysilane containing a hydrolyzed polymer of metal alkoxide or polysilicic acid as a silicon array If base film as a protective film (JP-A-54-41111, etc.) ), a proposal has been made to use a polysilicate film containing one or more metal oxides as a protective film (JP-A-53-76010), but in both cases, the main component of the protective film is a hydrolyzed polymer, and the Hydrolyzed polymers have an insufficient degree of polymerization, and cannot be said to be a reliable and effective means for preventing contact wear and improving moisture resistance.

〔the purpose〕

The present invention is intended to solve these problems, and its purpose is to coat a thin metal magnetic medium with a protective film using colloidal glue and a raw material contained at least in Tokuden's metal alcoquid. In particular, it is an object of the present invention to provide a magnetic memory having significantly improved durability such as contact abrasion resistance and moisture resistance.

〔overview〕

In the magnetic storage body of the present invention, a metal magnetic thin medium is coated on a metal-polished nonmagnetic substrate, and the following (A) and (B) (A) grain sizes of 1 to 80 are coated on the metal magnetic thin medium. Millimicron's colloidal silica (B) Coating a cured film made of a phased gold raw material containing at least one metal alkoxide and/or metal chelate compound having an element selected from Groups Ⅰ and ③ of the Periodic Table. It is characterized by being forced.

The cured film contains colloidal silica in an amount of 50% to 50% by weight.
It is characterized by containing 95% by weight and 5% to 50% by weight of a polycondensate of a metal alkoxide and/or a metal chelate compound.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

Example 1 Mirror finish (surface finish, 0.05 μm or less, Ace2
N1-P alloy is plated to a thickness of approximately 25 μm as non-magnetic alloy plating on a disc-shaped aluminum alloy substrate with a surface roughness of 0 rn/see” or less, and the plated surface is polished to a surface roughness of 0.03 μm or less, P alloy plating thickness 20
After forming a steel surface with a thickness of μm, Co-
The N1-P alloy was plated to a thickness of about 0.07 pm. Further, the following treatment liquid was applied onto the metal magnetic thin olfactory medium by a spinner method, and heat treated (200° C., 20 hours) to harden and completely coat the magnetic disk to a thickness of 0.08 μm.

(Treatment liquid) ■FA sol (manufactured by Catalyst Kasei) 8% by weight Particle size 15-30 mm colloidal glue 30 wt solution Tetrabutoxy7 zirconium 2% by weight isopropanol - 45% by weight Normal butanol 45% by weight Example 2 All magnetic disks were prepared in the same manner as in Example 1, except that the treatment liquid shown in 1 below was used.

(Treatment liquid) Methanol/Ricasol 8% by weight Particle size 14-20 mm Colloidal silica 30% liquid Pentaethoxy7 tantalum 2ft 1% Inbanol 45% by weight Normal phthanol: 45% by weight Example 5 A magnetic disk was produced using the treatment liquid shown below, which was applied by a constant speed up-up method, and other conditions were the same as in Example 1.

(Treatment liquid) IPA sol...30% by weight Atron NTa-755 (manufactured by Nippon Soda)...30% by weight Dyclone Bs (manufactured by Daikin Industries)...Remainder Comparative Example 1 Same method as Example 1 However, a magnetic disk was manufactured using the processing liquid shown below.

(Treatment liquid) Tetramethoquinofuran......5% by weight Tetrabutoxysolane...2% by weight Isopropanol...465% by weight Normal phthanol... 46.5% by weight Comparative Example 2 A magnetic disk was prepared using the same method as in Example 1, except that the treatment liquid used was the liquid shown below (1-7).

(Treatment liquid) Tetrabutoxyzirconium 10 parts by weight Isopropanol 45 parts by weight Normal butanol 45 parts by weight Using each magnetic disk described in Examples and Comparative Examples, after recording operation, aSS test and moisture resistance test (85°C, 89°C) were performed. %R
E) was carried out, and the reproduction output was checked at every -foot interval, and the life span was defined as the point at which the output level was less than 90% of the initial reproduction output level.

The results are shown in the table below.

(cssEM) Contact, start, stop test A repeated operation test of the start and end of an operation in a recording/reproducing method in which the head and the magnetic disk surface are in contact at the start and end of the operation.

(Moisture resistance test) Accelerated test to confirm moisture resistance, 25℃, 50% RE condition (25℃, 504R) 15 years is 85℃
, 89%R)] corresponds to 26 days.

The value converted to time under the above conditions is shown in the box.

〔effect〕

As described above, the present invention has the effect of extending the durability against contact wear to more than twice that of the conventional example, and the durability of moisture resistance to approximately twice that of the conventional example.

This is because the main part of the protective layer is originally composed of particles whose main skeleton is a strong three-dimensional structure of loxane bonds.
The silanol groups on the surface of the core particles form strong bonds with other silanol groups, hydroxyl groups on the metal surface, and metal alkoxide and/or metal chelate compounds, making them extremely chemically stable. It has high adhesion with other materials, and exhibits excellent durability against high temperature, high humidity conditions and immersion in water. In addition, the protective layer made of colloidal force is closer to the underlying metal body in thermal expansion coefficient than the protective layer made of metal alkoxide or semimetal alkoxide such as tetraalkoxysilane, and the internal stress of the protective layer is smaller. This results in
It has high protection strength and improved wear resistance for the head.

In order to realize the above characteristics in a protective body, the protective body must contain more than 50% by weight of colloidal strength,
In order to further improve the adhesion between the protective layer and the metal magnetic thin olfactory medium, the polycondensate of metal alkoxide and/or metal chelate compound must be contained in an amount of 5% by weight or more.

The present invention has made it possible to provide a magnetic storage body that can cope with increased density and accompanying reduction in the flying height of the head.

The present invention is also applicable to floppy disks, magnetic tapes, magneto-optical disks, etc. whose substrates are made of plastic.

that's all Applicant: Suwa Seikosha Co., Ltd. Agent: Patent Attorney Mogami

Claims (1)

[Claims] (11. A metal magnetic thin olfactory medium is coated on a mirror-polished non-magnetic substrate, and the following is applied on this metal magnetic thin medium),
and (B) (A) colloidal glue having a particle size of 1 to 80 mm/micro/(B) at least one metal alkoxide and/or metal chelate compound having an element selected from Groups II and V of the Periodic Table; A magnetic memory material characterized by being coated with a hardened cash coating made from a phase material containing few seeds.
5% by weight of a metal alkoxide and/or a metal chelate compound polycondensate of 5% to 50% by weight.