JPH01263932A - Magnetic recording body and production thereof - Google Patents

Abstract

PURPOSE:To obviate an increase in signal errors and degradation in S/N and to prevent the attraction of the recording medium to a magnetic head so as to improve the durability thereof by forming microprojections to a protective layer coating the magnetic layer on a substrate and adjusting the same to a surface condition of a specific density. CONSTITUTION:The magnetic recording medium consists of the substrate 1, the magnetic layer 4 covering the substrate and the protective layer 6 covering the magnetic layer 4. The microprojections of >=1 pieces per 4mum<2> are provided on the surface of the layer 6. The microprojections are formed by subjecting the overlying thin film or thin protective film constituting the protective layer to a surface roughening treatment with a noble metal. The surface roughening with the noble metal is preferably executed by a method of immersing the substrate into a surface roughening liquid of the noble metal such as gold or silver to adsorb the noble metal particles thereon. The attraction of the recording medium to the magnetic head is thereby prevented and the durability of the medium is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording body used in a magnetic recording device such as a magnetic disk device and a method for manufacturing the same.

(Prior Art) In recent years, the importance of magnetic disk devices in file storage devices has increased, and the recording density thereof has been significantly improved year by year. Until now, so-called coated disks, in which a mixture of iron oxide magnetic powder and an organic resin binder is coated on a substrate and then polished, have been widely used as magnetic recording media. In coated type disks, in addition to being able to contain a lubricant in the mixed layer of magnetic powder and organic resin binder, the magnetic layer is thick, about 0.4 μm or more, and the surface roughness Rmax is about 0.4 μm or more. Around 04 μm (Ra is -0.
Since it is relatively large (approximately 0.01 μm), it is possible to provide a sufficiently thick lubricating film without attracting the head, and it has excellent durability against contact and sliding with the magnetic head. However, in order to achieve even higher recording densities in the future, it will be necessary to make the magnetic recording layer thinner, which is a disadvantage for coated disks. Therefore, thin-film magnetic disks whose magnetic recording layer is a magnetic thin film formed by plating, sputtering, vapor deposition, or the like have begun to be used as high-density magnetic recording bodies.

Conventionally, as a substrate for a thin film magnetic disk, a substrate such as an aluminum alloy substrate on which a Ni alloy plating film is formed and polished (hereinafter referred to as a Ni alloy plating substrate) is used. Normally, this substrate is produced by plating a Ni alloy plating film several lim to several tens of μm thick on an aluminum alloy substrate, and then mirror-polishing the surface to a surface roughness Ra of about 0.004 μm or less using polishing methods such as lapping and boring. Used (Research and Practical Application Report 26-2, p. 471, 1977)
.

However, when a magnetic thin film is formed on this substrate, the thickness of the magnetic thin film, which is several times smaller than that of the magnetic recording layer of a typical coated disk, is smooth and uniform, and there is no place for lubricant to accumulate on the magnetic disk surface. Therefore, only a very small amount of lubricant can be held, resulting in a problem that the C85 (contact start/stop) durability of the magnetic head is poor. Furthermore, when a liquid lubricant is applied to the surface of a mirror-polished magnetic disk, adhesion occurs between the liquid lubricant and the magnetic rad slider surface, which has a smooth surface, and the disk is likely to be damaged when the disk is started.

For this reason, there is a method in which thin concentric streaks (texture) are formed by contacting a tape containing abrasive grains while rotating a mirror-polished Ni alloy plated substrate as described above.
As seen in Japanese Patent Application Laid-Open No. 59-82626, Ni
The alloy plated substrate is polished to an Ra of 0.006 to 0.
A method of achieving a surface roughness of 0.10 μm has been proposed.

(Problem to be solved by the invention) However, in this method of forming a rough surface by machining, signal errors may occur due to relatively large abrasive grains in the polishing abrasive grains or foreign matter mixed during polishing. This tends to cause thick polishing streaks, and it is difficult to obtain a uniformly moderately rough surface over the entire surface of the disk. There is a problem in that these non-uniform polishing streaks affect the characteristics of the magnetic layer, resulting in deterioration of recording/reproducing characteristics and servo signal quality. moreover,
In machining, the surface roughness obtained is almost determined by the size of the abrasive grains used, making it impossible to finely control the surface roughness and making it difficult to increase the density of the polishing streaks. Therefore, in order to prevent head adsorption and provide a lubricating film of sufficient thickness, it is necessary to considerably increase the surface roughness, which poses a problem of deterioration of electromagnetic conversion characteristics. In addition, such precision machining is difficult to mass produce at once, and there are also problems in productivity.

An object of the present invention is to provide a magnetic recording medium that does not increase signal errors or decrease S/N, prevents adhesion to a magnetic head, and has excellent durability, and a method for manufacturing the same.

(Means for Solving the Problems) The magnetic recording body according to the present invention consists of a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer. It is characterized by having microprotrusions of 1 (!I or more).

The method for manufacturing a magnetic recording body according to the present invention provides a magnetic recording body having one or more microprotrusions per 4 μm2 as the surface shape of the protective layer, in which microprotrusions are formed on a substrate constituting the base, a thick base film, or a thin base film. microprotrusions are formed on the magnetic layer, or microprotrusions are formed on the upper thin film or thin protective film constituting the protective layer.

Further, in the method for manufacturing a magnetic recording body according to the present invention, microprotrusions are formed by performing noble metal surface roughening treatment in the process of forming a magnetic recording body having one or more microprotrusions per 4 μm2 as the surface shape of the protective layer. It is characterized by

Requirements such as the height and size of the microprotrusions on the surface of the protective layer of the magnetic recording body used in the present invention differ depending on the conditions under which the magnetic recording body is used. Head type, structure, material, head flying height, lubricant, protective film type,
Depending on head and disk conditions such as film thickness, conditions such as the height and shape of the microprotrusions are selected in each case in order to prevent the magnetic head from sticking and to obtain a magnetic recording medium with excellent durability. It is desirable that the height of the microprotrusions be smaller than the flying height of the head and larger than the film thickness of the lubricant. According to the inventors' studies, it has become clear that the influence of the amount of microprotrusions (density of microprotrusions) is more significant in preventing head adsorption and improving durability. The higher the density of microprotrusions, the better the results, but 1/4 μm2
By increasing the density to more than 300 ml, there was a remarkable effect in preventing adhesion to the magnetic head and improving durability.

The substrate used in the magnetic recording medium of the present invention is a substrate, or a substrate coated with various additional films, such as a substrate coated with a thick base film, and a thin base film coated on the base film. There are some that are coated with Metal substrates such as aluminum alloy, copper, brass, iron, and titanium are usually used as substrates, but the surfaces of these are oxidized,
Non-metallic substrates such as glass, ceramics, resin, etc., or substrates made of composite materials thereof, which have been subjected to chromate treatment or a suitable activation treatment, can also be used. Base thick film,
As the underlying thin film, it is preferable to use an electroless plating film of NiP or NiB, but it is also possible to use an electroplating film, a dry plating film by sputtering, vapor deposition, or the like. Furthermore, Mn, Fe is added to the NiP or NiB film.
, Co, AI, Ta, Li, Mg, Ti,
V.

Cr, Cu, Zn, Ge, y, Zr, Nb
l Mo, Ru, Rh, pb, Ags Au.

Sn, Sb, Te, Cs, W, Re, Pb, Bi, L
At least one element such as a, Ce, Pr, Nd, Ac, Ba, Pt, or Sm may be contained, and furthermore, P, B, C, N, O, S, or As.

Na, may contain nonmetals such as F, CI, Br, I, and Ca. Further, the base thick film and base thin film are not limited to Ni alloy films, but may include W, Mo,
Cu, 8n, Zn.

Re, Mn, Fe, Cr, Co, Au, A
at least one of g, AI, Ta, Ti, V, Si, etc.
It may also be a film made of a seed element, further containing P,
B, C, N, O, S, As, Na, F, CI
, Br, I, Ca, and other non-metals may be included.

Further, the thick base film and the thin base film do not need to each be a single layer, but may be multilayers with metal or various alloy films. The base thick film is usually 1 to 50μ in order to obtain a smooth surface precision.
After forming a film with a thickness of about m, preferably about 10 to 30 μm, it is polished. The base thin film is usually less than the thick base film, and is formed for the purpose of controlling the characteristics of the magnetic film thereon, eliminating the influence of the substrate on the magnetic film, and the like.

The magnetic layer used in the magnetic recording body of the present invention is a magnetic film containing at least Co, Ni, and Fe, but may also be an alloy film containing additional elements such as P and B, and may contain O. An oxide film containing N or a nitride film containing N may also be used. Other additive elements for the magnetic film used in the present invention are not particularly limited, but include Re, Mn, W, Li, Be, and Mg.

AI, Ru, Si, Mo, Zn, Sr, Y, Zr, Nb
, Cd, In, Sb, Ta, Ir, Hg, TI, Ti.

V, Or, Cu, Ga, Ge, Tc, Rb, Ra, Hf
, Rh, Pb, Ag, Au, Pt, Sn, Te.

Elements such as Ba, Cs, Os, Sc, Se, Pb, Bi, and lanthanum series rare earth elements may be included.

In addition to these elements, the magnetic film contains C, S, As,
Na, K, F, CI, Br, I.

Non-metals such as Ca may also be included. The magnetic film contains 10% or more of Co, Ni, and Fe, preferably 50% or more. P and B are contained in a maximum amount of about 30%, but preferably in a range of 15% or less. The magnetic film thickness is preferably in the range of 0.003 to 3 μm, but preferably 0.5 μm or less for high-density recording. One or more magnetic layers are used. In the case of two or more layers, magnetic films having the same composition, high density magnetic properties, etc. are laminated directly or via a nonmagnetic film. These films are formed by wet plating methods such as electroless plating and electroplating, or dry plating methods such as sputtering, vapor deposition, and ion blating.

The protective layer used in the magnetic recording medium of the present invention is a thin protective film, or one in which various additional films are formed under and/or on the thin protective film, for example, a thin protective film coated on an upper thin film. products, products with a lubricating film on top of this, products with an additional film on the top thin film and a thin protective film, and products with a lubricating film on top of this, etc. There is. Each of these films may have one layer or multiple layers. As a thin protective film, quartz glass, silicate glass, phosphate glass,
It is preferable to use an amorphous semimetal oxide generally called a glassy substance such as amorphous alumina, and an amorphous inorganic oxide film such as polysilicic acid, which is a condensation compound of tetrahydroxysilane, or a carbon film, but 513N4 Silicon compound films such as Rh, Ag and other metal films, Co oxide,
Oxide films such as CoNi oxide may also be used. These films can be formed by sputtering, vapor deposition, plasma C.
Formed by methods such as VD method plasma injection CVD method, dry plating method such as ion blating method, wet plating method such as electroless plating method and electroplating method, coating method, oxidation treatment method in solution, thermal oxidation method, etc. . As the upper thin film, it is preferable to use a thin film of Ni alloy, chromium compound, zirconium compound, etc., but the same materials as the above-mentioned thick base film and thin base film can also be used. As the lubricating film, a non-polar solid lubricant, a polar solid lubricant, a liquid lubricant, etc. are used (46th Applied Magnetics Society Research Circular, 46-5, 1986).

The noble metal surface roughening treatment used in the manufacturing method of the magnetic recording body of the present invention includes a method in which noble metal particles such as palladium, gold, silver, etc. are adsorbed by immersion in a noble metal roughening treatment liquid such as palladium, gold, silver, etc. in the process of forming the magnetic recording body. Preferably, palladium, gold, silver, platinum,
Noble metals such as rhodium and ruthenium may also be deposited. Magnetic recording materials, from the substrate to the protective film and lubricant film,
In most cases, it has a multilayer structure composed of metals (base metals) that have a greater ionization tendency than these noble metals. Therefore, the roughened state of the precious metal due to the minute protrusions is stable and less likely to be eluted or altered by subsequent film formation. Furthermore, these noble metals are non-magnetic and have little effect on the recording and reproducing characteristics of the magnetic recording medium. For this reason, noble metals were selected, but metals, alloys, and compounds that have a smaller ionization tendency and lower magnetism than the layers constituting the magnetic recording medium can also be used. As the noble metal surface roughening treatment method using a treatment liquid, an activation treatment method that is a pretreatment for plastic plating and the like can be used. This involves a two-step activation treatment method consisting of sensitization treatment using a tin chloride solution in an acidic region and activation treatment using a palladium chloride solution, and promotion using a tin-palladium colloidal catalyst solution and an acid/alkaline solution in an acidic region. One-step activation treatment method consisting of chemical treatment, one-step activation treatment method using tin-palladium complex catalyst solution performed in alkaline region, activation treatment method using noble metal salt solution that can be performed in acidic, alkaline, or neutral conditions, etc. There is.

The two-step treatment method that has been widely used in the past is described in U.S. Pat.
As shown in No. 702253, this is a process of sensitization treatment with a sensitizer solution consisting of a 5nC1□ solution, followed by activation treatment with an activator solution containing noble metal ions such as Pd, Au, Ag, etc. Pb, which has a catalytic effect on the plating reaction, is deposited on the substrate surface.
Fine particles such as Au and Ag adhere. An example of the treatment liquid composition is Narcus liquid (acidic): 5nC1□10g/l, H
Cl40ml/l.

Narcus liquid (alkaline): 5nC1□100g
/l, Rochelle salt 175g/l, NaOH 150g/l
I Weiss liquid: 5nSO425-40g/l, H2S
o45~20ml/l.

Alcohol 150-250ml/l.

Quinol 5-15m 1/1. Water 600-10100O/
IWalkar solution: 5nC1□90g/l, HCl5
Sensitizer liquid such as 5m1/1, Pd treatment liquid (1): PdC1□2g/l, HCl20
m1/l.

Pd treatment liquid (2): PdC1□0.15-0.25g
/l, HCl2.5ml/1°Au treatment solution: chloroauric acid 1
g/l, HCl2m/1°Ag treatment solution: silver nitrate 1.5g
An activator solution such as 1.2 ml/l of ammonia and 1.2 ml/l of ammonia can be used.

Further, as examples of commercially available liquids, Pink Schumer (sensitizer liquid), Red Schumer (activator liquid), etc. manufactured by Nippon Kanigen Co., Ltd. can be used.

In recent years, US Patent No. 301192 has been developed as a more uniform catalytic method.
As shown in No. 0, No. 3,532,518, and No. 3,650,913, a one-step treatment method consisting of a catalytic treatment using a soot/palladium colloidal catalyst solution and an acceleration treatment solution using an acid or alkaline solution has been carried out. As an example of the treatment liquid composition, T. Osaka et al.
et al), Journal of Electrochemical Society (J, Electrochemica)
l 5ociety), Volume 127, No. 5, 1980,
As shown on page 1021, liquid A: HCl60ml/l
-+Water-+PdPdC12l+SSnCl22H2O2
Colloidal liquid adjusted in the order of 2 and adjusted to 10100O by adding water, Solution B: HCl60ml1/1-+Water-+PdC1
Colloidal liquid adjusted in the order of □0.25g-+5nC1□2H2012g and made to 10100O by adding water, Solution C: HCl300ml-+Water-+PdC1□0g
-+ Na25nO31,5g-+5nC1□2H20
Colloidal liquid prepared by adding 27.5 g in this order, Solution D: HCl320ml-+Suishin PdC1□1g-+
Add 5nC1□2H2o4g in order and mature for 1 day, then add 5nC1
□For commercially available solutions, such as colloidal solutions prepared by adding 22H2O46, H solution: Hydrochloric acid-based colloidal solution H81 manufactured by Hitachi Chemical Co., Ltd.
Catabosite 4, a salt-based colloidal liquid made by Nijipreifest, and catalyst solutions such as 01B and F liquids, as well as those described by Osaka et al.
ctrochemical 5ociety), 12
As stated in Vol. 7, No. 11, 1980, p. 2343, G solution: NaOH 1 moL/1, H solution: HC 16m
ol/l, I liquid: H2S041.12mol/1,
J solution: ammonia 1mol/l, H solution: NH4BF41
For commercially available solutions such as mol/1, H solution: ADP2 manufactured by Hitachi Chemical.
01, M liquid An accelerating treatment liquid such as Access Relater 19 manufactured by Niji Play First can be used.

Furthermore, tin-palladium complex catalyst solutions that operate in alkaline regions have recently come into use. A commercially available solution is Activator Neogant 834 manufactured by Schering.

As a surface roughening treatment method using a noble metal salt solution carried out in an acidic, alkaline or neutral region, the activator liquid Pd treatment liquid (1), Pd treatment liquid (2), Au treatment liquid,
Ag treatment liquid or the like can be used.

The PdC1□ concentration is in the range of 0.0001 to 50 g/l, preferably 0.005 to 15 g/l, and the chloroauric acid concentration is in the range of 0.001 to 30 g/l, preferably 0.1 to 1
The range of 0g/l is 0.001 to 3 as silver nitrate concentration.
5 g/l, preferably a range of 0.1 to 15 g/l is used. HCI concentration is 0.001-500ml
/1, preferably from 0.1 to 100 m1/l, and the ammonia concentration is from 0.005 to 600 m1/1.
Preferably, a range of 0.1 to 150 m1/1 is used. In addition to Au, Ag, and Pd, noble metals include Pt and R.
Elements such as h, Ru, and Re can also be used, and as noble metal salts, in addition to chloride salts, sulfates, nitrates, organic acid salts, etc. can also be used. In addition to hydrochloric acid, sulfuric acid, nitric acid, organic acids, etc. can also be used. In addition, succinic acid, which acts as a pH buffer and complexing agent,
Additives such as organic acids such as acetic acid and surfactants may be added. Commercially available liquids include Activated Liquid (manufactured by Nippon Kanigen Co., Ltd.) for acidic liquids and Activated Liquids 2 and 3 (also manufactured by Nippon Kanigen Co., Ltd.) for alkaline liquids. The treatment method includes a treatment temperature range of 0 to 95°C, preferably 15 to 80°C;
The immersion treatment time is 1 second to 100 minutes, preferably 5 seconds to 15 minutes. The pH of the treatment solution is not particularly limited, although the pH of the treatment solution is usually 1 or less in the case of HCI acidity, but it may be carried out in the alkalinity of 14 or more or in the pH range therebetween.

The above processing method does not necessarily result in the formation of the microprotrusions that are the object of the present invention. The relationship with the condition of the surface to be treated is important, and it is desirable to carry out surface modification as a pretreatment. Acid treatment, alkali treatment, etc. are used for surface modification treatment. If the subsequent surface roughening treatment is acidic, acid treatment is used; if alkaline, alkali treatment is used. Adjustment processing conditions such as time are selected depending on the required roughness and surface roughening treatment.

The surface condition of the surface of the obtained magnetic disk can be examined using electron microscopy and a surface roughness meter. By such a treatment method, one or more microprotrusions can be formed per 4 μm2, and h is 0.0003 to 0.05 μm, preferably 0.01 μm.
The following surface roughness can be obtained.

The main object of the present invention is to improve the conventional problems by providing a surface shape of the protective layer with one or more microprotrusions per 4 μm2, thereby preventing adhesion with the magnetic head and providing magnetic recording with excellent durability. It's about offering your body. Therefore, it is clear that the present invention can also be applied to magnetic recording bodies in which additional layers of various materials are added above and below the magnetic recording layer for use in various applications. Magnetic recording media with such a configuration include, for example, glass substrates, ceramic substrates, alumite substrates, etc., which are made of carefully selected materials and processed with high precision. In order to satisfy the above requirements, a thick base film or a thin base film is not required, a base plate in which a thick base film for NLP plating is formed on an aluminum substrate has multiple layers of thick base films for the purpose of reducing defects, and magnetic properties of the magnetic recording layer. Chromium is added under the magnetic layer to control the crystal structure and facilitate manufacturing.
Pretreatment layers of molybdenum, titanium, silicon, gold, etc. are formed, and the magnetic recording layer is multilayered directly or via a nonmagnetic layer for the purpose of improving magnetic recording characteristics or multiplexing data information and servo information. Examples include those with a multilayer structure of multiple protective layers to further improve weather resistance.

(Function) In a magnetic disk that uses a magnetic thin film as a medium for high-density magnetic recording, the surface is smooth and there is no place for lubricant to accumulate, so the C8S durability with the magnetic head is poor, and if the amount of lubricant is increased, the magnetic There was a problem that adsorption occurred between the Herad slider and the surface. For this reason, it is widely practiced to create lines called texture by machining on the smooth disk substrate surface. However, this method of forming a rough surface by machining tends to cause signal errors due to non-uniform polishing roughness, and it is difficult to increase the density of polishing streaks because the roughness cannot be precisely controlled. In order to prevent head adsorption and provide a sufficiently thick lubricating film, it is necessary to considerably increase the surface roughness, which poses a problem of deterioration of electromagnetic conversion characteristics.

The inventors conducted a detailed study on the effects of disk surface roughness and shape on head adsorption, durability, electromagnetic characteristics, etc., and found that physical or chemical surface treatment is far more effective than mechanical processing. A fine and dense surface shape can be obtained and it is easy to control, and it is better to use micro protrusions (protrusions) formed by physical or chemical surface treatment than polishing streaks (concavities) formed by machining. It has become clear that the adsorption prevention effect is significantly greater. It has also been revealed that microprotrusions produced by physical or chemical surface treatment can be formed finely and densely, so a small surface roughness is sufficient, and good results can be obtained in terms of durability, electromagnetic conversion characteristics, etc. Conditions such as the height and shape of the microprotrusions are selected depending on the head and disk conditions in order to prevent adsorption with the magnetic head and obtain a magnetic recording medium with excellent durability. The influence of the amount of microprotrusions (density of microprotrusions) was significant. It has been found that the higher the density of microprotrusions, the better the results, and that the density is preferably one or more per 4 μm 2 . The present invention was brought about by obtaining such knowledge.

(Example) (Example 1) Sufficient hardness and good surface precision (Ra0.001μm, T
After cleaning and conditioning the surface of an alumina ceramic substrate (inner diameter 100 mm, outer diameter 210 mm) with IR≦20 μm and acceleration≦2G, noble metal roughening treatment was performed on the surface under the following conditions.

Precious metal surface roughening treatment (1) Sensitizer liquid (SnC1210g/l, HC140
mL/1,30°C) for 1 minute, then activator solution (PdC1□0.2g/l).

Immerse in HCl2ml/1.40°C for 2 minutes.

Precious metal surface roughening treatment (2) Sensitizer liquid (SnC125g/l, HCl5ml
/1.35°C) for 2 minutes, then soak in the activator solution (
Immersed in chloroauric acid (1g/l, HCl2ml/1.45°C) for 3 minutes.

Noble metal surface roughening treatment (3) Sensitizer liquid (SnC1□12g/l, HCl45
m1/1.35°C) for 3 minutes, then activator solution (silver nitrate 1.5 g/l, ammonia 1.2 ml/1.
50°C) for 4 minutes.

Precious metal surface roughening treatment (4) Sensitizer liquid (Pink Shoe 7- manufactured by Nippon Kanigen Co., Ltd.)
125°C) for 2 minutes, and then immersed in an activator solution (Red Schumer, manufactured by Nippon Kanigen Co., Ltd., 40'C) for 2 minutes.

Precious metal surface roughening treatment (5) Catalytic treatment liquid (D liquid: HCl320ml- + Suishin Pd
Add 1g of C1□→SSnCl22H2O4 and mature for 1 day, then immerse for 2 minutes in a colloidal solution prepared by adding 5nC1□22H2O46 (30°C), then accelerate treatment solution (K solution: NH4BF41mol/1,45°C) Soak for 3 minutes.

Precious metal surface roughening treatment (6) After immersing for 1 minute in the catalytic treatment liquid (F liquid, salt-based colloidal liquid Catabosite, manufactured by Niji Play Phi-Suite, 50°C), the acceleration treatment liquid (M liquid, Niji Play First, Accelerator 19) was added. .30°C) for 4 minutes.

Next, a magnetic thin film having a thickness of 0.08 μm was formed thereon by electroless plating using plating bath (1).

Plating bath (1) Plating bath composition Cobalt sulfate 0.07 mol/1 Nickel sulfate 0.035 mol/1 Sodium hypophosphite 0.25 mol/1 Sodium malonate 0.5 moL'1 Sodium malate 0.3 mol/1 Succinic acid sodium
0.4mol/1 ammonium sulfate
0.4 mol/1 plating condition Bath temperature 82°C Plating bath pH 9.2 (pH adjusted with aqueous ammonia at room temperature) Plating solution volume 1001 A thin protective film mainly composed of silicic acid polymer with a film thickness of 0.08 μm was formed by baking for 30 hours, and a lubricating layer made of a solid lubricant (monostearin) was further formed on top of this to form a thin protective film with a thickness of 0.08 μm. 6←---corresponds to the No. 1 noble metal roughening treatment number)
was created.

Electron microscopic observation of the surface of the obtained magnetic disk revealed that one or more microprotrusions were formed per 4 μm 2 . The structure of the thus obtained magnetic recording medium is shown in a model diagram as shown in FIG.

(Example 2) A magnetic recording body was manufactured using the same procedure as in Example 1, but in this example, after each noble metal roughening treatment in Example 1,
Electroless NLP plating solution manufactured by Nihon Kanigen Co., Ltd. (Schumer)
A step of forming a non-magnetic N1-P base thin film with a film thickness of 0.05 μm was added using the above method.

For each of the noble metal surface roughening treatments (1) to (6) used, the disk numbers are sequentially designated as (7) to (12).

Electron microscopic observation of the surface of the obtained magnetic disk revealed that one or more microprotrusions were formed per 4 μm 2 . The structure of the thus obtained magnetic recording medium is shown in a model diagram as shown in FIG.

(Example 3) After performing known pretreatment (cleaning, zinc substitution treatment, etc.) on an aluminum alloy substrate (inner diameter 100 mm outer diameter 210 mm),
A non-magnetic N1-P base thick film having a thickness of 25 μm was plated using an electroless NiP plating solution manufactured by Sibley First Co., Ltd. (posit). Next, after mirror polishing the base thick film surface,
After the adjustment treatment, noble metal roughening treatment was performed on the surface under the following conditions.

Precious metal surface roughening treatment (7) Sensitizer liquid (SnC127g/l, HC130m
After immersion for 2 minutes in the activator solution (PdC 120,05 g/l).

Immerse in HCl2ml/1.45°C for 1 minute.

Noble metal surface roughening treatment (8) After 3 minutes immersion in sensitizer liquid (SnC 1290 g/l, Rochelle salt 150 g/l, NaOH 100 g/l), activator liquid (chloroauric acid 1.5 g/l, HCl
2m1/1.25°C) for 2 minutes.

Precious metal surface roughening treatment (9) Sensitizer liquid (SnC125g/l, HCl15m
1/1.40°C) for 30 seconds, then activator solution (silver nitrate 1g/l, ammonia 2ml/1.40°C)
) for 2 minutes.

Precious metal surface roughening treatment (10) After 2 minutes of immersion in a sensitizer solution (Pink Schumer, manufactured by Nippon Kanigen Co., Ltd., 25°C), it was immersed for 2 minutes in an activator liquid (Red Schumer, manufactured by Nippon Kanigen Co., Ltd., 30°C).

Precious metal surface roughening treatment (11) Catalytic treatment liquid (Liquid A: HCl 60ml 1/1- + Suishin Pd
Adjust in the order of C1□Ig→5nC1□22H2O22,
After 1 minute immersion in the colloidal solution (colloidal solution adjusted to 10100O by adding water),
, 45°C) for 2 minutes.

Precious metal surface roughening treatment (12) After immersing in the catalytic treatment liquid (F liquid Niji Play Fist salt-based colloidal liquid Cataposit, 40°C) for 30 seconds, the acceleration treatment liquid (M liquid Niji Play Fist) immersed in a manufactured accelerator (19.25°C) for 2 minutes.

Noble metal surface roughening treatment (13) Activator liquid (PdC120.02g/l, HCl
2rn1/1, 65°C) for 5 minutes.

Noble metal surface roughening treatment (14) Activator liquid (chloroauric acid 0.8 g/l, HCl1
．． 5ml/l.

40°C) for 2 minutes.

Precious metal surface roughening treatment (15) Activator liquid (silver nitrate 1.2 g/l, ammonia 1
．． 2ml/1.45°C) for 3 minutes.

Precious metal surface roughening treatment (16) Activator liquid (activator liquid 1.50 manufactured by Nippon Kanigen Co., Ltd.)
℃) for 1 minute.

Next, a film with a thickness of 0.08 μm was applied on top of this under the same conditions as in Example 1.
A magnetic thin film was formed.

Next, a silicic acid monomer was spin-coated on top of this, and baked at 190°C for 1 hour to form a thin protective film mainly composed of a silicic acid polymer with a film thickness of 0.08 μm.Furthermore, a liquid lubricant (
A magnetic disk was fabricated by forming a lubricating layer made of perfluoroalkyl polyether.

For each noble metal roughening treatment (7) to (16) used,
Let the disk numbers be (13) to (22) in order.

As a result of electron microscope observation of the surface of the obtained magnetic disk, it was found that one or more microprotrusions were formed per 4 μm 2 . The structure of the thus obtained magnetic recording medium is shown in a model diagram as shown in FIG.

(Example 4) A magnetic recording medium was manufactured in the same manner as in Example 3, but in this example, after mirror polishing the surface of the base thick film in Example 3, electroless N1CuP plating manufactured by Shipley Fareastsa was applied. Non-magnetic N1Cu with a film thickness of 0.5 μm was made using
A step of forming a P base thin film was added.

Therefore, the adjustment treatment and each noble metal surface roughening treatment performed on the surface of the thick base film in Example 3 are performed on the surface of this thin base film in this example.

For each noble metal roughening treatment (7) to (16) used,
Let the disk numbers be (23) to (32) in order.

As a result of electron microscopy observation of the surface of the magnetic disk obtained, it was found that one or more microprotrusions were formed per 4 μm.The structure of the magnetic recording medium obtained in this way is shown in a model diagram as shown in Figure 4. It becomes like this.

(Example 5) A magnetic recording medium was manufactured using the same procedure as in Example 3, but in this example, after mirror polishing the surface of the base thick film in Example 3, plating was performed on it by electroless plating. A magnetic thin film with a thickness of 0.08 μm was formed using bath (2). Next, after an adjustment treatment, a noble metal surface roughening treatment was performed on the surface of this magnetic layer under the following conditions.

Noble metal surface roughening treatment (17) Sensitizer liquid (SnC1□Ig/l, HCl15m
1/1.25°C) for 1 minute, and then immersed in activator solution (PdC1□0.02gA).

Immerse in HCl (1.5 ml, 40°C) for 50 seconds.

Precious metal surface roughening treatment (18) Sensitizer liquid (SnC1□50g/l, Rossier)
I/ Salt 100g/l, NaOH50g/l, 25°C
) for 1 minute, then activator solution (chloroauric acid 0.5
g/l, HCl3. ml/1, 25°C) for 30 seconds.

Noble metal surface roughening treatment (19) Sensitizer liquid (Sn01□20g/l, Rochelle salt 50g/l, NaOH20g/l, 25°C)
After immersion for seconds, add activator solution (silver nitrate 1.5 g/l,
Soaked in ammonia (3ml/1.45°C) for 2 minutes.

Noble metal surface roughening treatment (20) After immersing in the catalytic treatment liquid (F liquid, salt-based colloidal liquid Catabosite manufactured by Niji Play Fist, 44.30°C) for 10 seconds, the acceleration treatment liquid (M liquid, manufactured by Niji Play Fist) Immerse in accelerator (19.25°C) for 1 minute.

Noble metal surface roughening treatment (21) Activator liquid (PdC1□0.01g/l, HCl
1m1/1.30°C) for 2 minutes.

Noble metal surface roughening treatment (22) Activator liquid (chloroauric acid 0.TgA, HCl 1.
5ml/l.

35°C) for 2 minutes.

Precious metal surface roughening treatment (23) Activator liquid (silver nitrate 1.5 g/l, ammonia 2
ml/1.25°C) for 1 minute.

Precious metal surface roughening treatment (24) Activator liquid (activator liquid 3.60 manufactured by Nippon Kanigen Co., Ltd.)
℃) for 2 minutes.

Therefore, the noble metal surface roughening treatment performed on the surface of the thick base film in Example 3 was performed on the surface of the magnetic layer in this example.

The disk numbers are (33) to (40) in order for the noble metal surface roughening treatments (17) to (24) used.

Electron microscopic observation of the surface of the obtained magnetic disk revealed that one or more microprotrusions were formed per 4 μm 2 . The structure of the magnetic recording medium thus obtained is shown in a model diagram as shown in FIG.

(Example 6) A magnetic recording medium was produced in the same manner as in Example 5, but in this example, after plating the magnetic layer in Example 5, an electroless NiP plating solution manufactured by Nippon Kanigen Co., Ltd. was applied on top of the magnetic layer. A step of forming a non-magnetic N1-P overlying thin film with a film thickness of 0.04 μm was added using (Schumer), and noble metal roughening treatment was performed on the surface of this overlying thin film under the same conditions as in Example 5. Ta. Therefore, the noble metal roughening treatment performed on the magnetic layer surface in Example 5 was
In this embodiment, the process will be carried out on the surface of this upper thin film.

Next, a thin protective film made of a carbon film having a thickness of 0.04 μm was formed thereon by RF sputtering.

For each of the noble metal surface roughening treatments (17) to (24) used, the disk numbers are given as (41) to (48) in order.

Electron microscopic observation of the surface of the obtained magnetic disk revealed that one or more microprotrusions were formed per 4 m2. The structure of the thus obtained magnetic recording medium is shown in a model diagram as shown in FIG.

(Example 7) A magnetic recording body was manufactured using the same procedure as in Example 5, but in this example, after plating the magnetic layer in Example 5, a film with a thickness of 0.03 μm was formed on it by RF sputtering. Chromium compounds (the main component is chromium, but some chromium oxide is included)
A top thin film was formed, and a thin protective film made of a carbon film having a thickness of 0.04 μm was formed thereon by RF sputtering. Next, noble metal surface roughening treatment was performed on the surface of this thin protective film under the following conditions.

Noble metal surface roughening treatment (25) Sensitizer liquid (SnC1□3g/l, HCl3ml
/1.30°C) for 1 minute, then soak in the activator solution (
PdC1□0.03g/l, HCl2m1/l.

35°C) for 1 minute.

Noble metal surface roughening treatment (26) Sensitizer liquid (Sn01270g/l, Rochelle salt 120g/l, NaOH50g/l, 25°C)
After soaking for a minute, activator solution (chloroauric acid 1.3g/l)
, HCl 5ml/1, 30°C) for 50 seconds.

Noble metal surface roughening treatment (27) After immersion in sensitizer solution (SnC1□30gA, Rochelle salt 60g/l, NaOH 30g/l, 35°C) for 2 minutes, activator solution (silver nitrate 1.5g/l, ammonia 4ml/l) 1.40°C) for 3 minutes.

Precious metal surface roughening treatment (28) After 45 seconds of immersion in the catalytic treatment liquid (F liquid Niji Play Fist salt-based colloidal liquid Cataposit 44.50°C), the acceleration treatment liquid (M liquid Niji Play Fist) immersed in a manufactured accelerator (19.25°C) for 30 seconds.

Noble metal surface roughening treatment (29) Activator liquid (PdC1□0.1g/l, HCl6
m1/1.30°C) for 3 minutes.

Noble metal surface roughening treatment (30) Activator liquid (chloroauric acid 1g/l, HCl 1.5
ml/l.

30°C) for 3 minutes.

Precious metal surface roughening treatment (31) Activator liquid (silver nitrate 1.5 g/l, ammonia 5
ml/1, 35°C) for 2 minutes.

Precious metal surface roughening treatment (32) Activator liquid (activated liquid 2.60 manufactured by Nippon Kanigen Co., Ltd.)
℃) for 2 minutes.

Therefore, the noble metal roughening treatment performed on the surface of the magnetic layer in Example 5 is performed on the surface of this thin protective film in this example.

For each of the noble metal surface roughening treatments (25) to (32) used, the disk numbers are given as (49) to (56) in order.

As a result of electron microscopic observation of the surface of the obtained magnetic disk, it was found that one or more smile protrusions were formed per 4 μm 2 . The structure of the thus obtained magnetic recording medium is shown in a model diagram as shown in FIG.

(Comparative Example 1) A magnetic recording body was produced in the same manner as in Example 3, but in this comparative example, the noble metal roughening treatment performed on the surface of the underlying thick film was omitted.

Electron microscopic observation of the surface of the obtained magnetic disk and measurement of surface roughness revealed that the surface was extremely smooth with no microprotrusions. The disk number thus obtained is assumed to be (57). The structure of this magnetic recording medium is shown in a model diagram as shown in FIG.

(Comparative Example 2) A magnetic recording body was produced in the same manner as in Example 7, but in this comparative example, the noble metal roughening treatment performed on the surface of the thin protective film was omitted.

Electron microscopic observation of the surface of the obtained magnetic disk and measurement of surface roughness revealed that the surface was extremely smooth with no microprotrusions. The disk number obtained in this way is assumed to be (58). The structure of this magnetic recording medium is shown in a model diagram as shown in FIG.

Regarding the magnetic disks obtained in Examples and Comparative Examples,
The presence or absence of head adsorption was investigated using a 3350 type Mn-Zn ferrite magnetic head. W! The head and each disk were set in the drive, and the coefficient of friction was measured before and after leaving the drive. The coefficient of friction before storage is 0.23~ for all discs.
Although it was in the range of 0.27, the comparative example disk (57)
In (58), the friction coefficient after standing for 100 hours is 1.
The number increased to more than 0, causing a head adsorption phenomenon. but,
In the examples, for the disks (1) to (56) obtained, the friction coefficient values after being left for 100 hours were 0.21 to 0.
It was within the range of 25, and there were no problems with head adsorption. Further, the magnetic disks obtained in Examples and Comparative Examples were subjected to a C85 (contact/start/stop) test using a 3350 type Mn-Zn ferrite magnetic head to determine the number of C8S cycles until scratches appeared on the surface. This number is 2
If it is used more than 10,000 times, it is considered to have sufficient durability for practical use. Comparative example discs (57) and (58) had scratches on the surface after several hundred cycles, and disc (57)
500 times, the disk (58) led to a head crash at C887,300 times. Disk obtained in Example (1
) to (56), no scratches were observed on the disk surface after 8.85 million cycles, and the durability was significantly improved. Furthermore, the recording and reproducing characteristics of the magnetic disks obtained in Examples and Comparative Examples were compared, and the characteristics of output, resolution, override, noise, and peak shift all showed similar values, and microprotrusions were observed in Examples. No effect was observed due to the formation of the magnetic recording material on the surface of the magnetic recording medium.

(Effects of the Invention) As shown above in the Examples and Comparative Examples, according to the present invention, a magnetic recording body consisting of a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer. , forming microprotrusions on the surface of the substrate constituting the base, the surface of the base thick film or the base thin film, the surface of the magnetic layer, or the top thin film or thin protective film constituting the protective layer;
By creating a surface condition with a protrusion density of 1 or more per m2, a magnetic recording body with excellent durability can be obtained without increasing signal errors or decreasing S/N, preventing adhesion with the magnetic head.

[Brief explanation of the drawing]

FIGS. 1 to 7 are schematic cross-sectional views of Examples 1 to 7 of magnetic recording bodies of the present invention, respectively. FIGS. 8 and 9 are cross-sectional views of magnetic recording bodies compared with Examples of the present invention. It is a schematic diagram. 1...Substrate, 2...Thick base film, 3...Thin base film,
400. Magnetic layer, 5... Upper thin film, 6... Thin protective film, 7... Lubricating film, 8... Noble metal roughening treatment layer.

Claims (7)

[Claims] (1) In a magnetic recording body consisting of a substrate, a magnetic layer covering this substrate, and a protective layer covering this magnetic layer, the surface shape of the protective layer has one or more microprotrusions per 4 μm^2. A magnetic recording medium characterized by: (2) A magnetic recording body consisting of a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer, wherein the base is a substrate, or the base is a substrate and an additional film covering the same. . A method for manufacturing a magnetic recording body having a protective layer having one or more microprotrusions per 4 μm^2 as a surface shape of the protective layer, characterized in that microprotrusions are formed on the substrate by a noble metal surface roughening treatment. (3) Consisting of a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer, wherein the base is a substrate and a base thick film covering the base, or the base is a base and a base coat covering the base. In a magnetic recording body consisting of a thick film and an additional film covering the same, the protective layer has a surface shape of one microprotrusion per 4 μm^2, characterized in that microprotrusions are formed on the thick underlying film by noble metal roughening treatment. A method of manufacturing a magnetic recording body having the above microprotrusions. (4) A magnetic recording body consisting of a substrate, a magnetic layer covering the substrate, and a protective layer covering the magnetic layer, the substrate comprising a substrate, a thick base film covering the base film, and a thin base film covering the base film. A method for manufacturing a magnetic recording body having a protective layer having one or more microprotrusions per 4 μm^2 as a surface shape of the protective layer, characterized in that microprotrusions are formed on the base thin film by noble metal roughening treatment. (5) A magnetic recording body comprising a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer, characterized in that minute protrusions are formed on the magnetic layer by noble metal roughening treatment. A method for manufacturing a magnetic recording material having a protective layer having one or more microprotrusions per 4 μm^2 as a surface shape. (6) Consisting of a base, a magnetic layer covering the base, and a protective layer covering the magnetic layer, wherein the protective layer is an overlying thin film and a thin protective film covering the overlying thin film, or the protective layer is an overlying thin film. and a thin protective film covering this, or the protective layer is a top thin film, a thin protective film covering this, and a lubricating film covering this, or the protective layer is a top thin film and an additional film covering this, and In a magnetic recording body, the protective layer is composed of an overlying thin film, an additional film covering this, a thin protective film covering this, and a lubricating layer covering this,
The surface shape of the protective layer is 4 μm^, characterized in that minute protrusions are formed on the upper thin film by noble metal roughening treatment.
A method for manufacturing a magnetic recording body having one or more microprotrusions per second. (7) Consists of a substrate, a magnetic layer covering the substrate, and a protective layer covering the magnetic layer, wherein the protective layer is a thin protective film, or the protective layer is formed on and/or below the thin protective film. A magnetic recording body comprising an additional film formed by the above method, characterized in that microprotrusions are formed on the thin protective film by noble metal roughening treatment, and the surface shape of the protective layer is one or more microprotrusions per 4 μm^2. A method of manufacturing a magnetic recording body comprising: