JPS6079527A - Magnetic storage body - Google Patents

Abstract

PURPOSE:To protect well a magnetic metallic thin film medium even when dust is contained, by forming a protective layer on the medium using a treating soln. contg. essentially colloidal silica and an organosilicon compound. CONSTITUTION:Co-Ni-P alloy plating of about 0.05mum thickness is formed as a magnetic metallic thin film medium, and a treating soln. consisting of 2wt% methanol silica sol, 1wt% gamma-glycidoxypropyltrimethoxysilane, 0.3wt% 0.05 N aqueous HCl soln. and the balance isopropanol is coated on the alloy plating to 800Angstrom thickness by a spinner method. Calcination is then carried out at 250 deg.C for 3hr in a thermostat to obtain a magnetic disk.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic storage body used in a magnetic storage device (magnetic disk device, magnetic drum device, etc.) Generally, a recording/reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body are configured. There are two main methods for recording and reproducing a magnetic storage device, as follows: The first method is to set the head and the magnetic storage surface in contact at the start of operation, and then write the required information on the storage device. By applying a rotation of At this time, the head and the magnetic storage surface are in the same state of contact wear as at the start of operation.The second method is to give rotation to the magnetic storage body in advance and then suddenly press the head onto the magnetic storage surface. to create a space equivalent to an air layer between the head and the storage surface,
This is a method of recording and reproducing in this state. In this way, in the first method, the head and the magnetic storage surface are in a contact friction state at the start and end of the operation, and in the second method, the head and the magnetic storage surface are in a contact friction state when the head is pressed against the magnetic storage surface. The frictional force generated between the head and the magnetic storage body in the contact friction state causes wear on the head and the magnetic storage body, and may eventually cause damage to the head and the metal magnetic thin film medium. Also, in this contact friction state, a slight change in the force of the head may cause the load applied to the knit to become uneven and cause scratches on the head and the surface of the magnetic storage body. comes into contact with the magnetic memory and the spatula r
A large frictional force acts between the head and the magnetic storage body, often resulting in destruction of the head and the magnetic storage body.

In order to protect the head and the magnetic memory from contact friction, abrasion, and destruction between the head and the magnetic memory, it is necessary to coat the surface of the magnetic memory with a protective film. Plating film (e.g. Or, Rh, M
There are methods such as coating the metal magnetic thin film medium (i-P, etc.), oxidizing the metal magnetic thin film medium, and coating the oxide film after the oxidation, but none of these methods are effective against the above contact wear phenomenon. ,. The power of tetraalkoxysilane that eliminates the above-mentioned drawbacks has also been proposed (Japanese Patent Publication No. 57-58731).
).

This protective coating made of polysilicic acid exhibits fairly good durability against contact friction between the head and the magnetic storage body and sudden contact wear between the head and the magnetic storage body. It can protect the metal magnetic thin film for a considerable period of time. However, dust is often drawn between the head and the magnetic memory, and the dust acts as an abrasive and damages the head and magnetic memory. The polysilicic acid is not sufficient as a protective film in terms of wear resistance and impact resistance, since the abrasion particles produced by the abrasion further abrade the head and the magnetic storage body. Furthermore, since the starting material of polysilicic acid coatings is tetraalkoxysilane, even if the hydrolyzate is dehydrated and condensed, only a very insufficient condensation state can be achieved, and the durability against water is still insufficient. I have to say it.

The purpose of the present invention is to sufficiently protect the metal magnetic thin film medium even when the above-mentioned dust is drawn in, and to prevent the metal magnetic thin film medium from being exposed to damage under high temperature and high humidity conditions for a long period of time or when immersed in water. An object of the present invention is to provide a magnetic memory having a protective coating that does not cause any adverse effects.

That is, the magnetic storage body of the present invention includes: A metal magnetic thin film medium is coated on a non-magnetic disk-shaped substrate, and a protective film made of a material containing at least the following substances is coated on the metal magnetic thin film medium. has been done.

(A) Dull silica, a colloid with a particle size of 1 to 100 millimeters (B) General formula R' n-8i -(OR24-@)
(In the formula, R' is a hydrocarbon group having 1 to 6 carbon atoms, a vinyl group, a methacryloxy group, an epoxy-containing group, or an organic group having a halogen; -R2 is a hydrocarbon group having 1 to 6 carbon atoms or hydrogen; represents 0, 1.2).
Seed organosilicon compounds.

The colloidal silica of (A) is a particle with a particle size of 1 to 100 millimicrons that has a three-dimensional structure of strong nasiloxane bonds as its main skeleton, and the surface of the particle has -8i-OH groups and -
OH ions are present. In this way, the colloidal silica has strong siloxane bonds, so it is extremely chemically stable and exhibits excellent durability even under high temperature and high humidity conditions and when immersed in water. The protective coating mainly composed of 1-tetraalkoxysilane has a coefficient of thermal expansion closer to that of the underlying metal body than the protective coating made of 1-tetraalkoxysilane, and the internal stress of the protective coating is small. As a result, the strength of the protective coating is high and the wear resistance of the head is improved.◎ The organosilicon compound (B) chemically bonds with the colloidal silica (A), and like colloidal silica, it also chemically bonds with the underlying metal body. It forms a protective coating and enhances the ability of the head to absorb impact forces.

The organosilicon compound is hydrolyzed by adding water or dilute acid in the presence or absence of a diluent, the concentration is adjusted as necessary, and colloidal silica is added to form a treatment solution. After coating, the whole is fired. Next, examples will be given to explain in detail.

Example 1゜Mirror finish (surface roughness 0.05μ or less, ACC5Q
Approximately 5% N1-P alloy is applied as non-magnetic alloy plating on the disc-shaped aluminum alloy substrate (@/eec2 or less).
After plating to a thickness of 0 μm and polishing this plating to a mirror finish with a surface roughness of 0.03 μm or less and a thickness of 60 μm, Oo-N is applied as a metal magnetic thin film medium on top of the plating.
The i-P alloy was plated to a thickness of approximately 0.005 μm. Furthermore, on the Oo-Ni-P alloy plating, the following processing solution was applied to a film thickness of 800X using a spinner method.Next, the disk-shaped disk was baked at 250℃ for 3 hours in a constant temperature bath, and magnetically applied. It was made into a disc.

(Treatment liquid) Methanol silica sol...2% by weight (Nissan Chemical Products) γ-glycidoxypropyltrimethoxysilane...1% by weight 005N hydrochloric acid aqueous solution...03% by weight Isopropyl alcohol...Remainder Example 2゜A magnetic disk was prepared by applying the same method as in Example 1, but using the treatment liquid shown below and baking it at 250°C for 3 hours.0 (Treatment liquid) Methanol silica sol...・2% by weight tetramethoxysilane ...1% by weight 005N hydrochloric acid aqueous solution ...0
4% by weight n-butyl alcohol... Residual Comparative Example The same method as in Example 1 was used, except that the treatment liquid was as follows: A disk-shaped disk was coated with the liquid shown below and baked at 250°C for 3 hours. It was made into a disc.

(Treatment liquid) Tetramethoxysilane...5% by weight 0,05N hydrochloric acid aqueous solution...1.5% by weight Butyl alcohol
... Remainder In a recording and reproducing method using each of the magnetic disks shown in Comparative Example and Examples 1 and 2, in which the head and the magnetic disk surface are in a contact state at the start and end of the operation, this operation start When the test was repeated 10'000 times, approximately 10% of the wear marks on the magnetic disk of the comparative example peeled off, but on the magnetic disks of Examples 1 and 2, there was no peeling. Ta.

In addition, a magnetic disk was immersed in pure water (liquid temperature 40°C), left for 48 hours, taken out, water removed, and the same operation start and end test repeated ioooo times as described above. In the magnetic disk, approximately 80% of the wear marks with the head were cracked, but in each of the magnetic disks of Examples 1 and 2, there were no cracks. Although metal is used as the disc-shaped substrate, it is clear that plastic or the like can also be used, and the presence or absence of non-magnetic alloy plating, the material, and the material of the magnetic thin film medium do not matter.

Claims (1)

[Claims] A metal magnetic thin film on a mirror-polished nonmagnetic substrate. A medium is coated, and the following (A
) and (B), (A) Colloidal silica with a particle size of 1 to 100 millimicrons (B) General formula R'? l-8i -(OR2)4-n
(In the formula, R' is a hydrocarbon group having 1 to 6 carbon atoms, a vinyl group, a methacryloxy group, an organic group having epoxy, or an organic group having halogen, and R2 is a hydrocarbon group having 1 to 6 carbon atoms or hydrogen, 1. A magnetic memory body characterized by being coated with a protective film made of a material containing at least one organosilicon compound represented by the following: 0.1.2.