JPS6070525A - Magnetic storage body - Google Patents

Abstract

PURPOSE:To form a protective film for a magnetic storage body having superior durability even at high temp. and humidity or immersion in water and superior wear resistance by using starting materials including specified substances. CONSTITUTION:This magnetic storage body is obtd. by coating a thin film medium of a magnetic metal formed on a nonmagnetic disklike substrate with a protective film contg. essentially colloidal alumina of 1-100mum particle size and at least one kind of organosilicon compound represented by a general formula R<1>n-Si-(OR)<2>4-n (where R<1> is 1-6C hydrocarbon, vinyl, methacryloxy, a group contg. epoxy or an org. group having halogen, R<2> is 1-6C hydrocarbon or H, and n is 0, 1 or 2). The protective film protects well the thin film medium even when dust is stuck, and the film prevents unfavorable influence from being exerted on the medium even when it is held at high temp. and humidity for a long term or immersed in water.

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.).

In general, there are two types of recording and reproducing methods for a magnetic storage device that includes a storage and reproducing magnetic head (hereinafter referred to as a head) and a magnetic storage body.

The first method is to set the head and the magnetic storage surface in contact at the start of operation, and then give the storage body the required rotation to create a space between the head and the storage surface for an air layer. This is a method of creating and recording/playing in this state. With this method, the rotation of the magnetic storage body stops when the operation is finished;
At this time, the head and the magnetic storage surface are in a state of contact wear, similar to when the operation was started. The second method is to create a space between the head and the storage surface by an air layer by rotating the magnetic storage medium in advance and suddenly pressing the head onto the magnetic storage surface. This is a method of recording and reproducing in this state. Thus, in the first method, the head and the magnetic storage surface are in a frictional contact state at the start and end of the operation, and in the second method, the head and the magnetic storage surface are in a frictional contact state when the head is pressed against the magnetic storage surface.

The frictional force generated between the head and the magnetic storage body in these contact friction states causes the head and the magnetic storage body to wear out,
This may eventually cause damage to the head and the gold-layer magnetic thin film medium. Further, in the contact friction state, a slight change in the posture of the head causes the load applied to the head to become uneven, which may cause scratches on the surface of the head and the magnetic storage body. Furthermore, during recording and reproduction, the head suddenly comes into contact with the magnetic storage body, and a large frictional force is generated between the head and the magnetic storage body, which often results in destruction of the head and the magnetic storage body.

In order to protect the head and the magnetic memory from such 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. Traditionally, metal plating films (e.g. Cr, Rh, N) have been used as protective films.
There are methods such as coating the gold-layered magnetic thin film medium (i-p, etc.), oxidizing the gold-layer magnetic thin film medium, and plugging the oxidation layer after the oxidation. It is not.

A protective coating made of polysilicic acid formed using a hydrolyzate of tetraalkoxysilane that eliminates the above drawbacks has also been proposed (Japanese Patent Publication No. 57-58731). Contact W rubbing,
It exhibits fairly good durability against sudden contact abrasion of the head with the magnetic storage body, and can protect the metal magnetic thin film for a considerable period of time even in high temperature and high humidity conditions.

However, there are many cases where dust is drawn between the head and the magnetic recording body, and the dust acts as an abrasive adhesive and wears down the head and the magnetic recording body. Polysilicic acid cannot be said to be sufficient as a protective film in terms of wear resistance and blood impact resistance since it causes wear of the magnetic memory. In addition, since the starting material of the polysilicic acid film is tetraalkoxysilane, even if its hydrolyzate is dehydrated and condensed, it can only form a very insufficient ring plate state, which has a limited durability when soaked in water. I have to say that the trench is insufficient.

Therefore, in order to improve the above drawbacks, it has been proposed that one or more metal oxides selected from BaQ, sr□, etc. be included in the polysilicate film to form a protective film. (JP 56-76010) However, it is extremely difficult to uniformly disperse the metal oxide directly into a tetraalkoxysilane hydrolyzate solution, and even if a protective film is formed with a thickness of about 100 OA, Convex portions occur, making it difficult to obtain the required characteristics. Furthermore, if an attempt is made to remove the aggregated metal oxide, all of the added metal oxide will be removed, and no effect will be obtained from the addition. As described above, in reality, it is impossible to improve the quality of the polysilicate film, and in order to add metal oxides, it is essential to devise measures from the material standpoint.

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

That is, in the magnetic storage body of the present invention, a metal magnetic thin film medium is coated on a non-magnetic disk-shaped substrate, and a material containing at least some of the following (A) and (B) is used as a raw material on the metal magnetic thin film medium. It is coated with a protective film.

(A) Colloidal alumina particles f11 to 100 millimicrons (B) General formula g'n-s;-(OR24-n) (In the formula, R1 is a hydrocarbon having 1 to 2 carbon atoms, a vinyl group, and a methacryloxy group. , an organic group having an epoxy-containing group or a halogen, R2 is an ashing hydrogen group having 1 to 2 carbon atoms or hydrogen, and n is 0, 1.2). Compound.

The colloidal alumina (A) is a particle with a particle size of 1 to 100 millimicrons whose main skeleton is a strong bond between aluminum and oxygen with a three-dimensional structure, and the surface of the core particle has >Al-OH groups and -OH groups. ions exist. In this way, colloidal alumina has strong bonds, so it is extremely chemically stable, and is resistant to temperature, high humidity conditions, and immersion in water.
Shows excellent durability. In addition, a protective coating made of colloidal alumina as a main component has a coefficient of thermal expansion closer to that of the underlying metal body than a protective coating made of tetraalkoxysilane.
The internal stress of the protective coating is small. This increases the strength of the protective coating and improves the abrasion resistance of the head.

The organic silicate compound (B) is chemically bonded to the colloidal alumina (A), and like colloidal alumina, is chemically bonded to the underlying metal body to form a protective film and enhance the ability to reduce the impact force of the head. 0 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 alumina is further added to form a treatment liquid.

After coating the metal magnetic thin film medium, the whole is fired.

Next, a detailed explanation will be given with reference to examples.

Example 1 Mirror finish (surface roughness, 0.05 μm or less, ACC30
NI-P alloy is applied as a non-magnetic alloy plating onto a disc-shaped aluminum alloy substrate which is
After polishing this plating to a mirror finish with a surface roughness of 0.03 μm or less and a thickness of 60 μm, co-Ni-P is applied as a metal magnetic thin film medium.
The alloy was plated to a thickness of approximately 0.05 μm. Furthermore, C0-
On the N1-P alloy plating, the following treatment solution was applied to a film thickness of 800 mm using a spinner method. Next, the disc-shaped disc was fired in a constant temperature oven at 250'0 for 6 hours,
It was made into a magnetic disk.

(Treatment liquid) Aluminium/L/(Nissho Chemical Products) 3″Mjxk%γ
- Glycidoxypropyltrimethoxysilane 1 chick 0.05 N hydrochloric acid aqueous solution 03 Difficult isopropyl alcohol Remainder Example 2 A disk coated using the same method as Example 1, but using the treatment liquid shown below. A magnetic disk was prepared by firing at 250°0 for 3 hours.

(Treatment liquid) Alumina sol 2 Separate I Tetramethoxysilane 1 005N hydrochloric acid aqueous solution 0.4 Mother I n-butyl alcohol Remaining Comparative Example The same method as in Example 1 was used, except that the treatment liquid used was the one shown below. The coated disc was heated at 250°C for 55 minutes.
The time-sintered product was used as a magnetic disk.

(Treatment liquid) Tetramethoxysilane 5% N-hydrochloric acid aqueous solution 1.5% by weight n-butyl alcohol Remainder Using each magnetic disk shown in Comparative Example and Examples 1 and 2, head and magnetic disk surface were prepared. In a recording and reproducing method in which the head and the head are in contact at the start and end of the operation, we repeated the start and end of the operation 10,000 times. Although 10% of the magnetic disks peeled off, there was no peeling in each of the magnetic disks of Examples 1 and 2.
After leaving it for a while, I took it out, removed the moisture, and repeated the same test as above, starting and ending the operation 10,000 times. On the magnetic disk of the comparative example, about 80 scratches with the head were cleared by 71. In each of the magnetic disks of Examples 1 and 2, there were no cracks.

In the comparative examples and examples, metal was used as the non-magnetic disc-shaped substrate, but plastic etc. can also be used, and it is clear that the presence or absence of non-magnetic alloy plating, the material, and the material of the magnetic thin film medium do not matter. be.

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

Claims (1)

[Claims] A metal magnetic thin film medium is coated on a mirror-polished nonmagnetic substrate, and the following (A) and (
B) (A) Colloidal plv alumina (B,) with a particle size of 1 to 100 millimicrons General formula R゛n-s+-(oR2), -n (in the formula, R. is a hydrocarbon group having 1 to 6 carbon atoms, R2 is a hydrocarbon group having 1 to 2 carbon atoms or hydrogen, n
represents O+ 1+ 2. ) at least 1
1. A magnetic memory body characterized by being coated with a protective film made of a material containing at least a seed organosilicon compound.