JPS6113425A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium for high-density recording provided with practicable durability by coating a magnetic medium and non-magnetic metal in this order on a substrate, coating the surface of the non-magnetic metal with an oxide and coating a bindable lubricating agent thereon. CONSTITUTION:The iron oxide such as Fe3O3 or gamma-Fe2O3 or metal or alloy such as Co-Ni is coated as a magnetic medium 2 on the substrate 1. Re or the like is coated as the non-magnetic metal 3 on the medium 2 and is then calcined in an oxidative atmosphere contg. oxygen or ozone to form the oxide coating 4 consisting of the non-magnetic metal on the surface. The lubricating agent 5 to be coated thereon is required to be bindable as the oxide film 4 of the non-magnetic metal. Silane which binds to said film by reacting securely therewith is most effective as such lubricating agent component. There are some lubricating agent components which bind to the film 4 by adsorbing thereto according to the polarity of -O-.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to magnetic recording bodies such as magnetic discs, magnetic drums, and magnetic tapes used in magnetic recording devices.

(Prior Art and its Problems) In recent years, magnetic disks and the like in which a magnetic metal thin film is used as a recording medium (magnetic layer) have begun to be used as high-density magnetic recording bodies. Ritori, which uses a magnetic metal thin film as a recording medium, has a high saturation magnetic flux density, so it is possible to make the medium thin, and it also has a high coercive force, making it suitable for high-density recording. The advantage is that thin films can be easily produced by methods such as electroless plating, electroplating, and sputter deposition.

By the way, the demand for higher recording densities in magnetic recording devices is increasing year by year. -Magnetic recording media such as magnetic tapes and floppy disks, in which it is essential to reduce the medium separation length, are used in contact with a magnetic head or in a state close to it in order to maximize recording density. In addition, in the case of magnetic disks in which the magnetic head is used by being levitated at a minute distance from the magnetic recording material, as the performance of magnetic recording devices becomes higher, the total load on the magnetic head is reduced in order to reduce the flying distance, and at the same time, the contact starts.・Stop (contact・
A start/stop, C55) type head flotation system is adopted. For this reason, an effective method for preventing damage to the magnetic recording medium caused by the magnetic head is to provide a protective layer on the surface of the magnetic metal thin film, and efforts have been made to improve durability. The protective layer must have wear resistance, magnetism, smoothness, strong adhesion, and be as thin as possible. Various studies have been made for these purposes, but all have been insufficient.

Conventionally, there is a method proposed in which a high hardness metal such as Rh or Cr is coated on the surface of the medium by electroplating. ◎Another method is to use metals such as Or, W, 8i0. ,Man! ! There are methods of coating the media surface with oxides such as 0° by vapor deposition, sputtering, etc., but the adhesion is insufficient, and since it is manufactured in a vacuum system, there are problems with productivity. C as a protective layer with excellent adhesion.

Or, by oxidizing the surface of a Co-N1 magnetic metal thin film, Co
, -04 oxide film was proposed.

For example, Japanese Patent Publication No. 42-20025 proposed a method of oxidizing Cot present on the surface of a magnetic metal containing Cof in an oxidizing atmosphere with controlled temperature and humidity to form a protective oxide film. In order to obtain a strong oxide film, methods such as anodic oxidation, acid treatment, and firing in air have been proposed. However, due to variations in the thickness of the protective oxide film and variations in the thickness of the residual magnetic layer, the uniformity of the reproduction output is impaired, and there is a problem in that multiple bits of noise sometimes occur. Therefore, as a method to improve this, US Patent No. 4,1
As shown in No. 24,736, a method was proposed in which an intermediate layer serving as a barrier to oxidation treatment is formed between a magnetic layer of a storage medium and a magnetic metal layer containing Cof to obtain a protective oxide film. However, this method has the following problems: First, it is difficult to oxidize the magnetic metal layer containing Co uniformly (LJ), and if the oxidation treatment is lightened, the magnetic metal layer remains. Adversely affects electromagnetic conversion characteristics. Furthermore, if a strong oxidation treatment that oxidizes the entire magnetic metal layer is performed, a thick intermediate layer is required to prevent the oxidation treatment from affecting the magnetic metal medium, which results in a substantial increase in the protective film thickness. , leading to a decrease in recording density. Second, as the number of laminated layers of the recording medium, intermediate layer, protective layer, and thin film increases, the process becomes more complicated and productivity is impaired.Also, if the intermediate layer is thinned to less than 1000x, pinholes in the intermediate layer will occur. It is not possible to completely prevent the influence of oxidation treatment on magnetic metal media.(Objective of the Invention) The object of the present invention is to improve the drawbacks of the prior art described above,
Our objective is to provide a magnetic recording medium for high-density recording with practical durability.Furthermore, we aim to maintain the uniformity of the reproduction output of the magnetic recording medium having a protective oxide film and to simplify the manufacturing process. Particularly, it is an object of the present invention to provide a method for producing a high-quality and inexpensive magnetic recording body. (Structure of the Invention) The magnetic recording body of the present invention has a magnetic medium and a non-magnetic metal coated on a base body in this order. , the surface of the non-magnetic metal is coated with an oxide of the non-magnetic metal, or the oxide of the non-magnetic metal is coated with a lubricant that can adhere to the oxide. It is characterized by Further, in the method of the present invention, the nonmagnetic metal is oxidized by heat treatment.

(Detailed description of the structure) Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial sectional view of the magnetic storage body of the present invention, and the base body 1 is made of aluminum alloy or anodized alumite.

N1-P plating film, Cr, FeN1. Aluminum alloy coated with Mot or W, or plastic such as polyester, polyimide, polyamideimide, or Cr,
On this base body 1, which is a metal such as FeNilMo or W, or a ceramic or glass plate such as silicon nitride or alumina, Fe104 gr is applied as a magnetic medium 2.
- Iron oxides such as Fe 20H or Co-Ni.

Co-N1-P, Co-Mn-P, Co-Ni-M
n-P, Co-ne, Co-Mn-Re-P,
Co-Cr, Co-V, Co-Pt.

Co-N1-Pi, Co-Pt-Crg Co-Pt
-V, Co-Rh.

Coating a metal or alloy such as Co-NiMo or Co-8m on the magnetic medium 2 as a non-magnetic metal 3.

Ru, Os, Pd, Rh, Ir, Mn, Zn
, Sn, Cr, Mo, W.

Ni, Cu or Ag or alloys thereof (may contain one or both of B and P)io, 1 μm
After coating, an oxide coating 4 of the non-magnetic metal is formed on the surface by firing in an oxidizing atmosphere containing gold such as oxygen or ozone. Another partial cross-sectional view shows that, similarly to FIG. 1, a base 1, a magnetic medium 2, a non-magnetic metal 3, and an oxide film 4 of the non-magnetic metal 3 are coated in this order, and the oxide film 4 is coated with lubricant. Agent 5
is coated.

The lubricant 5 needs to be able to adhere to the non-magnetic metal oxide film 4, and such a lubricant has the following structure: 0 Rf-0-%CF, - CF, -0 CFt-04Rf
.

G-C, F'! ni-0-ecFt-CF2-0 episode CF,
-0 end C, F,,'-G'.

Rf-0+CFt-cp, -oﾞF鵞-0揄C1F,
=G However, Rf is CI! F, +2 where l is an integer of 1 or more m and n are integers of 10 or more.

k is 0 or an integer greater than or equal to 1 oG or G' is -COO
H, -COOC,H,, yu□ (j is an integer of 1 or more).

-CiHliOH (i is an integer of 0 or 1 or more), NH,
.

-CHt=CH,, -8i(C,Hth+1)gXs
= g (h is an integer of 1 or more 1g is 0, 1 or 2, X is Ct or -OH or OCf mountain f+1 (' is an integer of 1 or more)), or -A-8i (ChH*b+1)gXs
=g (h*geX is the same as above. Also, A is C, H, N.

0.8 of one or more elements).

For example, -C0-NH-CH2-CHt-, -NH-C
Ht-CH(0H)-CHt-CH,-,-CO
-CH! -CHt +, -0-CH, -α, -, -5-
-NH-C-NH-CH, -CH, -, etc.

The functional group G in the above general formula reacts strongly and adheres to the non-magnetic metal oxide film 4, and therefore is not removed by the sliding movement of the head.

This effect is especially noticeable among functional groups -8@ (Ch H! h+
1) g = g (h is an integer greater than or equal to 1, g is 0, 1 or 2, X is ct or expanded -OH or QC, H!, (f is 1
The silane represented by an integer greater than or equal to )) is the most effective.
It is adsorbed and fixed to the oxide film 5 of the metal.

Other lubricants that can be used are Per 70 locarboxylic acids, Perfluoro alcohols, Per 70 local yy y acid esters, Per 70 fatty acid esters of alcohols, Per 70 loalkyl alkoxysilanes, Fluorosilicone, Par 7
0-roalkylsulfonic acid, ammonium per-70-roalkylsulfonate, nh-alkylalkoxysilane, higher fatty acid, higher fatty alcohol, higher fatty acid ester, higher fatty acid amide, unsaturated higher fatty acid, long-chain aliphatic hydrocarbon, etc. Yes In addition, after coating the lubricant 5t, it may be baked at 50 to 300°C.

Next, the present invention will be explained in detail with reference to Examples.

(Example) An aluminum alloy disk whose surface has been finished flat and smooth by machining is coated with a Keru phosphor plated film, and a magnetic medium is placed on the base weight whose surface is mirror-finished to a surface roughness of 50X. As No. 2, a cobalt-nickel-phosphorus alloy was plated to a thickness of ro, os μm. Next, a non-magnetic metal 3 is placed on top of this magnetic medium 2.
A nickel-phosphorus alloy was plated to a thickness of 500 mm. Next, the surface of the nickel-phosphorus alloy used as the non-magnetic metal 3 was heated in air at 300°C for 2 hours.
A magnetic disk was made by oxidizing the non-magnetic metal 3 and coating it with nickel oxide as the oxide film 4. (Sample 1)
) A magnetic disk was prepared in the same manner as in Example 1, except that nickel oxide was coated with 2/ containing Si2/ having the following structure as a lubricant 5. )G-CtF4+0-CtFi
sO-CF, ceC, F, -G, where G is -Co-NH-C
HH6-81 (ocax) ap = q = 37 Same as Example 2 except that as lubricant 5, 100X of linear Par70 lower kill polyether having the following structure was used.
90 (Sample 3) HO-CHt-CtFa (0-CtFaze 0-CF to C
tFa -CHt-OH where p=lO, q=100 After plating copper as the non-magnetic metal 3 on the magnetic medium 2 to a thickness of 500X in the same manner as in Example 1, it was plated in air at 200°C for 500X. The surface of the copper alloy used as the non-magnetic metal 3 was 400X oxidized by baking for a time to coat copper oxide as the oxide coating film 4 on the non-magnetic metal 3. The lubricant 5 has the following structure. A magnetic disk was made by coating with linear perfluoroalkyl polyether l5ol having the following structure (Sample 4).
) CxFi 10CtFa capital 0-CF, +qc, F, -G
However, G is 10000,)(,-8i(QC,H,).

p=200. q=20 In the same manner as in Example 1, except that the non-magnetic metal 3 was plated to a thickness of nickel-copper-phosphorus alloy T3001 and plated in air at 25%.
A magnetic disk was produced by firing at 0° C. for 3 hours to form a nickel-copper oxide layer on the surface of the non-magnetic metal 30 to a thickness of 1 x oi. (Sample 5) In the same manner as in Example 2, except that the non-magnetic metal 3 was plated to a thickness of 1800× silver and baked at 300°C for 1 hour in air containing ozone to form silver oxide on the surface of the non-magnetic metal 30. A magnetic disk was manufactured by forming the magnetic disk to a thickness of txooX. (Sample 6) A nickel-chromium-phosphorus alloy was plated to a thickness of 500X as the non-magnetic metal 3 in the same manner as in Example 2, and fired in air at 280°C for 2 hours to obtain the non-magnetic metal 30. A magnetic disk was made by forming nickel-chromium oxide on the surface to a thickness of 300X.

(Sample 7) Same as Example 2, except that the non-magnetic metal 3 was plated with nickel-molybdenum-phosphorus alloy t-5ool,
Sintered in pure oxygen at 260°C for 6 hours.

A magnetic disk was fabricated by forming nickel-molybdenum oxide to a thickness of t-4ooX on the surface of the non-magnetic metal 3.

(Sample 8) A nickel-indium-phosphorus alloy was plated as the non-magnetic metal 3 to a thickness of 600 mm in the same manner as in Example 2, and the surface of the non-magnetic metal 3 was baked at 230°C for 10 hours in air. A magnetic disk tube was made by forming nickel-indium oxide to a thickness of 300 mm. (Sample 9) Same as Example 2, except that a nickel-tungsten-phosphorus alloy was plated to a thickness of 2001 as the non-magnetic metal 3,
A magnetic disk was made by baking at 280°C in air for 2 hours to form a 100X thick nickel-tungsten oxide on the surface of the non-magnetic metal 3. Wood 0 (sample 10) was prepared in the same manner as in Example 2. However, the non-magnetic metal 3 is plated to a thickness of nickel-vanadium-phosphorus '17001, and fired in air at 270°C for 3 hours to form a nickel-vanadium oxide on the surface of the non-magnetic metal 3 to a thickness of 300X. O (Sample 11) A magnetic disk was made by forming O (sample 11) in the same manner as in Example 2, except that cadmium was used as the non-magnetic metal 3 to a thickness of 200X. A magnetic disk was made by baking at 290C in air for 2 hours to form cadmium oxide on the surface of the non-magnetic metal 30 to a thickness of 100 mm (Sample 12) (Comparative example) Magnetic properties shown in Example 1 Cobalt-phosphorus alloy on top of the medium
After plating to a thickness of 00X, immersing it in a dimethyl nitric acid aqueous solution for 5 minutes, washing with water, drying, and baking at 260°C in air for 4 hours to form a layer of cobalt oxide, dimethyl silicone oil was applied. A magnetic disk was made by coating it to a thickness of 50X. (Comparative sample 1) The magnetic medium shown in Example 1 was plated to a thickness of nickel-phosphorus alloy T-400i, and on top of that was plated to a thickness of cobalt-phosphorus alloy 1400X, and 1%
After immersing in a nitric acid aqueous solution for 5 minutes, washing with water, drying, and baking at 260°C for 4 hours in the air, a layer of oxide was formed on the nickel-phosphorus alloy to create a magnetic disk. Sample 2) 50% of nickel phosphorus alloy was placed on the magnetic medium shown in Example 1.
A magnetic disk was produced by plating to a thickness of 0X and anodizing in a 1% sulfuric acid solution to oxidize the surface to 100X.

(Comparative sample 3) Magnetic disk and load 15 shown in the example and comparative example
When a C88 test was conducted 20,000 times using a magnetic head having a slider made of Ji' p AbOs.TiC sintered body, no scratches were observed on the surfaces of either the disk or the head of the magnetic disk of the example.

Furthermore, after 100,000 cycles of the C88 test, the magnetic disks of Samples 1 and 5 had a slight amount of abrasion powder, but the magnetic disks of Samples 2 to 3 and 6 to 12 showed no change in the surface at all. However, the surface of the comparative sample magnetic disk was worn out after 5,000 cycles, and a large amount of abrasion powder was generated. When the surface of the comparative sample magnetic disk was observed, it was found that there were countless defects, and the cracks deteriorated the wear resistance. I found out that there is O
Furthermore, when the number of errors was measured for the magnetic disks of Samples 1 to 12 in Examples and Comparative Samples 1 to 3 of Comparative Examples, the results are shown in the table.

As described above, it has been found that a magnetic disk having an oxide film formed on the surface as a non-magnetic alloy tube protective film in an oxygen-containing atmosphere has excellent durability and has a very small number of errors.

Table (Effects of the Invention) As described above, according to the present invention, a magnetic memory with good durability can be obtained, and the manufacturing process can be simplified, resulting in high quality and
A manufacturing method for producing an inexpensive magnetic storage body is obtained.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are partial cross-sectional views of the magnetic storage body of the present invention. In Figures 1 and 2, 1 is the base body, 2 is the magnetic medium, and 3
3 is a non-magnetic metal, 4 is an oxide of a non-magnetic metal 3, and 5 is a lubricant. FIGS. 3 and 4 are partial cross-sectional views of a magnetic storage body of a comparative example. In Figures 3 and 4, l is the base body, 2 is the magnetic medium, and 3
is cobalt oxide, 4 is a lubricant, and 5 is a nonmagnetic metal. Iwa l Figure No. 21 ri No. 3 Figure top - -2-λ1; Meniz) to -lr:
Rei 4 Fu-l″″F Gaitai

Claims (7)

[Claims] (1) A magnetic storage body characterized in that a magnetic medium, a nonmagnetic metal, and an oxide of the nonmagnetic metal are formed in this order on a base. (2) Non-magnetic metal is W, Cr, Mo, Ni, Cu, Ag
, Pe, Ru, Os, Pd, Rh, Ir, Mn, Zn,
2. The magnetic memory according to claim 1, which is a metal made of one or more elements selected from Sn, or a metal to which at least one element of B and P is added. (3) A magnetic storage body characterized in that a magnetic medium, a nonmagnetic metal, an oxide of the nonmagnetic metal, and a lubricant are formed in this order on a base. (4) Non-magnetic metal is W, Cr, Mo, Ni, Cu, Ag
, Re, Bu, Os, Pd, Rh, Ir, Mn, Zn,
4. The magnetic memory according to claim 3, which is a metal made of one or more elements selected from Sn, or a metal to which at least one element of B and P is added. (5) The magnetic memory according to claim 3 or 4, wherein the lubricant is a linear perfluoroalkyl polyether or a linear perfluoroalkyl polyether having a functional group. (6) After coating a magnetic medium on a base body and further coating a non-magnetic metal on the medium, forming an oxide film of the non-magnetic metal on the surface by heat-treating in an atmosphere containing oxygen. A method for manufacturing a magnetic memory body characterized by: (7) Non-magnetic metal is W, CrMo, Ni, Cu, Ag,
Re, Ru, Os, Pd, Rh, Ir, Mn, Zn, S
The method for manufacturing a magnetic memory body according to claim 6, which is a metal made of one or more elements selected from n, or a metal to which at least one element of B and P is added. .