JPS5938924A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the rusting of a ferromagnetic metal and to improve running durability by forming the thin film of the ferromagnetic metal contg. oxygen on a nonmagnetic substrate, and forming a compd. which can suppress the hydration of ions by acting on the ionized ferromagnetic metal so as to exist in the peripheral of said film. CONSTITUTION:A ferromagnetic metallic layer 2 is vapor deposited on a nonmagnetic material substrate 1 in a vacuum contg. a trace of O2, whereafter a layer 3 adsorbed with a compd. selected from bivalent phenol, diallyl ketone, quinone, nitroso compd., etc. having the effect of suppressing the hydration of ions when the oxide of the ferromagnetic metal ionizes by adsorbing moisture in a high humidity atmosphere or the like as a rust preventive on the layer 2 is formed thereon. Then a lubricant layer 4 is formed thereon. The rust preventive layer is formed by coating as soln. and drying, or exposing in the rust preventive vapor. Otherwise a mixture of said rust preventive and a lubricant is incorporated into the microholes in the magnetic layer by a method of coating said mixture on the magnetic layer or the like. The long-term prevention of the rusting of the layer 2 for which conventional rust preventives having no O2 have no effect in preventing rusting is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention belongs to the field of magnetic recording using electromagnetic conversion, such as magnetic tapes and magnetic disks.

Structure of conventional example and its problems Plastic film such as polyester, polyimide, etc.
Fe, Ni, and C are deposited on the surface of a substrate made of a nonmagnetic material such as an aluminum plate or a glass plate by vapor deposition, ion plating, sputtering, etc. in a vacuum.

Alternatively, a magnetic recording medium on which a ferromagnetic metal thin film mainly composed of these alloys is formed is suitable for high-density recording such as video signal recording.

The thickness of the ferromagnetic metal thin film is as small as 0.01 to 0.6 μm,
Therefore, if it is left in high humidity, especially in an environment where there are large temperature changes and condensation occurs, the surface is likely to corrode, and if this corrosion progresses to a certain extent, it will affect the electromagnetic conversion characteristics and cause head damage.

Attempts have been made to suppress this corrosion, which degrades practical properties such as wear resistance, with rust preventive agents. Known agents can be used. Examples of these include alkylamines, basic nitrogen compounds such as fatty acid salts of alkylamines, alkyl phosphates, alkyl chemistries, etc. Phosphoric acid esters and a+ < phosphorus compounds such as phosphoric esters 9 petroleum sulfonates - strephonates such as toumahoganic acid sulfonate, dinonylnaphthalene sulfonate + monooleate, methyl esters of organic acids There are certain esters, metal soaps of petroleum acid and abietic acid, specific cal-H-hinic acid derivatives such as σ mercaptostearic acid, and mildly vaporizable esters such as dicyclohexylammonium nitrite, diisopropylammonium nitrite, and lebamate. For information on these rust preventive agents for bulk metals, see, for example, "Metal Surface Technology Hard" new edition, edited by the Metal Surface Technology Association (published in 1960, publisher: Nikkan Kogyo Shimbun), pages 1417-1439. It is described in.

A ferromagnetic metal thin film that contains oxygen by introducing a small amount of oxygen gas into the vacuum system during the formation of the ferromagnetic metal thin film has a higher coercive force than a film that does not contain oxygen, and the bond between the substrate and the film is improved. Adhesion strength is also improved.

Surface corrosion resistance is also greatly improved, but corrosion resistance under harsh environments is still not at a sufficient level, and the application of rust preventive agents is desirable for this purpose as well. However, the above-mentioned rust inhibitors that are suitable for ferromagnetic metal thin films that do not contain oxygen have almost no rust-preventing effect on oxygen-containing ferromagnetic metal films, and on the contrary, they promote corrosion. It has become clear that there are cases.

Conventional rust inhibitors for bulk metals act directly on the metal to stabilize the surface condition of the metal (this means that
For example, OG, Tranb specified in the following document
anelli & V, Carassiti: 'Adv
ance in Corrosion Science
and Technology. 'Vo1.1, p.
147 (PLENUM Press. New Year
k. 197o)) However, since the surface of a ferromagnetic metal thin film containing oxygen is covered with an oxidized layer of ferromagnetic metal, when such a rust preventive agent is used, It is thought that the rust preventive passes through the oxide layer and acts on the metal inside the oxide layer, causing the oxide layer to no longer fulfill its original role as a protective layer.

Therefore, it became necessary to find a new rust preventive agent for ferromagnetic metal thin films containing oxygen.

As mentioned above, ferromagnetic metal thin film magnetic recording media have the potential to dramatically improve recording density compared to conventional coated magnetic recording media, but in order to achieve this high density, It is necessary to reduce the spacing loss as much as possible by making the gap of the magnetic head small and by smoothing the surface of the magnetic recording medium. The specific spacing value is required to be 500 Å or less, and more preferably 300 Å or less.0 Although the head touch and running performance can be considerably improved by finely controlling the surface shape of the magnetic recording medium, the essential It is difficult to significantly reduce the contact area between the head and the medium, and the tendency for the coefficient of friction to increase is unavoidable.

The rust preventive agent used in the present invention is. Ferromagnetic metal ions.

It is a compound that has a specific polar group that binds to the oxide ion or the hydroxide ion.

Although it prevents rust by adsorbing it onto a ferromagnetic thin film, it is clear that it does not have much of an effect on improving head touch and running performance, and that excessive adhesion can cause head clogging. became.

On the other hand, the use of various lubricants has been proposed for the purpose of lowering the coefficient of friction between the head and the magnetic recording medium, but unless special types are excluded, these lubricants do not show any rust-preventing effect and may act as corrosion promoters. It has become clear that there may be cases.

Purpose of the Invention The present invention aims to further improve the corrosion resistance of a magnetic recording medium using a ferromagnetic metal thin film containing oxygen as a magnetic layer, and to
The purpose is to improve running performance and durability.

Structure of the Invention The present invention provides a magnetic recording medium in which a ferromagnetic metal thin film containing oxygen is formed on a non-magnetic substrate. The present invention is characterized by the presence of a compound that suppresses the ferromagnetic film, and is further characterized by the presence of a lubricant on the ferromagnetic film.

Description of Examples First, as a non-magnetic substrate, polyester, polyamide,
A film sheet made of plastic such as Polyhedo, a metal plate made of metal such as aluminum or stainless steel, a ceramic plate, a glass plate, etc. are used.

The surface properties of ferromagnetic metal thin film magnetic recording media are very small, with a magnetic layer thickness of about 0.1 to 0.6 pm.

It largely depends on the surface shape of the substrate. therefore,
JP-A-63-116116, JP-A-67-377
A substrate with finely controlled surface shape as described in Japanese Patent No. 19 is immediately desirable as a substrate for the present invention.

Regarding ferromagnetic metal thin films containing oxygen, Japanese Patent Publication No. 56-2
They are described in JP-A No. 3208, JP-A-63-42010, JP-A-56-15014, JP-A-57-37719, and the like.

The ferromagnetic thin film obtained by continuous oblique evaporation in a vacuum containing oxygen gas consists of an aggregate of fine columnar crystals, and the surface of each columnar crystal is covered with an oxide layer of the ferromagnetic metal that makes up the crystal. It is being said. This oxide layer is thin, with a thickness of about 1 to 200 nm, and contains many defects such as crystal structure defects and hydrates, and when the thin film is placed in high humidity, these defects are removed. In this case, ferromagnetic metal ions, ions of their oxides, or ions of their hydroxides are easily hydrated to form hydrated oxides of ferromagnetic metals...in other words, rust.
...becomes.

As a result of studies conducted by the present inventors, compounds that act on these ionized ferromagnetic metals (i.e., ferromagnetic metal ions, ions of their oxides or hydroxides) and suppress the hydration of these ions are found to be oxygen-containing compounds. The conclusion was that it is the best rust preventive agent for ferromagnetic metal thin films. In the following text, the above compound will be referred to as a rust inhibitor.

Examples of rust preventives include dihydric phenols.

There are diallyl ketones, alkylphenols, naphthols, quinones, nitrone compounds, oxime compounds 2, etc., and these are shown in more detail as follows.

Dihydric phenols include hydroquinone, resorcinol,
Pure phenols such as catechol, and their alkylamino, nitro, nitrone, and halogeno substituted products, such as 2-methylhydroquinone, 4-), f-luresorcinol, 5-methylresorcinol, 4-methylpyrocatechol, 2° 6-dimethylhydroquino7.4.6
-dimethylresorcinol, 2,6-dimethylresorcinol, 2-isopropyl-6-methylhydroquinone, 2-tert-butylhydroquinone, 2.6-
Sheet-tert-butylhydroquinone, 4-tert
-butylcatechol, 2-amylsorcinol, 2-nitroresorcinol, 2. It refers to es-dichlorohydroquinone, etc. Diallyl ketones refer to benzophenone and its derivatives.

Tato, t(d', benzophenone, 4-methylbenzophenone, 3-methylbenzophenone, 3,4-dimethylbenzophenone, 4.a'-dimethylbenzophenone,
Alkyl substituted products such as 4-ethylbenzophenone, 4-hydroxybenzophenone, 4.4'-dihydroxybenzophenone, 2,3.4-trihydrobenzophenone,
2, a-dihydroxybenzophenone, 2,
2', 5, 6'-tetrahydrobenzophenone,
Hydroxybenzophenones such as 2.3', 4.4', and 6-pentahydroxybenzophenone, and aminobenzophenones such as 4-aminobenzophenone and 4.4'-diaminobenzophenone.

Or benzophenones having two or more types of substituents,
fc refers to 4-methoxy-2-hydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,6-cyhydroxy-4-methoxybenzophenone, etc.

Alkylphenol refers to an alkyl substituted product of -valent phenol, such as 0-cresol.

m-cresol, p-cresol, 0-ethylphenol, m-ethylphenol, p-ethylphenos <1/
, 2, 3-dimethylphenol, 2,6-methylphenol, 2.6-dimethylphenol, 3,4-dimethylphenol, 3.6-dimethylphenol, 2,
4.6-trimethylphenol, 2,4.5-trimethylphenol, 6-ituprobyl-2-methylphenol, 2-isopropyl-6-methylphenol, p-t
ert-butylphenol, 2.6-tert-butyl-p-cresol, 4.4'-methylenebis-2゜6-tert-butylphenol, 2.6-cymethyl-4-tert-butylphenol, 2-tert
-aluminum-4-methylphenol, 2-methyl-4,
6-tert-butylphenol.

2.4.6-Tart-Butylphenol.

etc.

Naphthols include α-naphthol, β-naphthol,
Pure naphthols such as 1,2-naphthalenediol, 1.4゜6-naphthalenediol, 1.2,6.8-naphthalenetetraol, and nitro, nitroso, amino,
Halogeno-substituted naphthols, e.g. +1-chloro-2
-Naphthol.

2.4-dichloro-1-naphthol, 1-nitro-2-
naphthol, 1,6-sinitro 2-naphthol, 1-
It refers to nitron-2-naphthol, 2-nitrono-1-naphthol, 1-amino-2-naphthol, and the like.

Quinones include p-benzoquinone, 0-penzquinone,
1.2-naphthoquinone, 1.4-naphthoquinone, 2.6
- Naphthoquinone, anthraquinone.

9-10-phenanthrenequinone, unsubstituted quinone such as diphenoquinone, methyl-P-benzoquinone, 2,
3-Dimethyl-P-benzoquinone.

Methylquinones such as 2-methyl-1,4-naphthoquinone and 2-methylanthraquino-7, 2,6-cyhydroxy-P
-benzoquinone, tetrahydroxy-P-benzoquinone, 6-hydroxy-1,4-naphthoquinone, 2,3-dihydroxy-1,4-naphthoquinone, 6,8-dihydroxy-1,4-naphthoquinone, 2-hydroxyanthraquinone.

1+2-dihydroxyanthraquinone, 1.2°3-trihydroxyanthraquinone, 1,2.4-trihydroxyanthraquinone, 1. Hydroxyquinones such as 2,6-trihydroxyanthraquinone, 1,2,6-)dihydroxyanthraquinone, 1,2,7-trihydroxyanthraquinone, 2-amino-anthraquinone,
1. Aminoquinones such as 2-diaminoanthraquinone,
Nitroquinones such as 1-nitroanthraquinone and 1,6-sinitroanthraquinone, halogenquinones such as 2,6-dichloro-P-benzoquinone, tetrachloro-P-benzoquinone, and tetrafuromo-P-penzoquinone, or two or more types of substitutions. Quinones having groups such as 2
．． It refers to 6-dichloro-3°6-cyhydroxy-P-benzoquinone, 1-methyl-2-hydroxy-1,4-naphthoquinone, and the like.

A nitroso compound is an organic compound having both a hydroxyl group and a nitroso group, and includes nitrosophenol-based and nitrosonaphthol-based organic compounds. in particular,
1-Nitroso-2-naphtho-, 2-nitroso-1-naphthol, 1-nitroso-2-naphthol, 4-nitroso-2-methoxy-1-phenol, 4
-Nitroso-2-ethoxy-1-phenol, 4-nitrosocarvacrol, 6-nitro7-0-riL/7''-
, JL, 4-nitron-m-cresol 0-nitronphenol, 2-nitrone resorcin, 4-nitrosoresorcin, 2-nitrosoresorcin monomethyl ether, N-nitron phenylhydroxylamine ammonium salt (cuperone), p-nitronphenol , 2-nitroso-1-naphthol-4-sulfonic acid, 6-nitrone-8-quinolitool, and the like.

The oxime compounds include benzyloxime, glyoxime, benzaldoxime, benzamide oxime, α-benzoin oxime, acetophenone oxime, penzophenone hesime, dimethylglyoxime, salicylaldoxime, and the like.

These rust inhibitors are applied to at least the surface of the ferromagnetic thin film.

If possible, the effect can be exerted by making it exist inside or in contact with the interface with the base on which the ferromagnetic thin film is formed. The appropriate amount is magnetic recording medium 1
-The IJ O, 6 to 6 o o my If so, there are two methods: diluting it with a solvent and applying it to the surface of the ferromagnetic thin film, applying anti-fouling vapor to the surface of the ferromagnetic thin film, and, if the magnetic recording medium is in the form of a tape, leaving it on the back side. A method in which the tape is transferred onto the surface of a ferromagnetic thin film when it is wound.

Well-known means such as the following can be used. In addition, by using a non-magnetic substrate on which a rust preventive agent has been made to exist in advance and forming a ferromagnetic metal thin film on this substrate, the rust preventive agent is made to be present especially on the side of the ferromagnetic metal thin film that is in contact with the substrate. 0 A method for manufacturing a substrate containing a rust preventive agent includes, for example, a method in which at least the surface of the non-magnetic substrate is made finely porous by etching or the like, and a rust preventive agent is contained therein;
For plastic film substrates, there is a method in which a rust preventive agent is added to the substrate raw material or a surface shape imparting agent during film formation.

There are ways to make it penetrate. The rust preventive agent may exist uniformly within the nonmagnetic substrate, may be unevenly distributed near the surface thereof, or may be segregated in the form of fine particles. however,
It is desirable that it exists at least on the magnetic layer forming surface.

The rust preventive content of the non-magnetic substrate is at least 0.00 to 10% by weight at least near the surface on the side where the magnetic layer is formed (that is, within 1000 depths from one surface), and more preferably 0.
．． 0.01 to 1% by weight is suitable.

Inside the substrate, it may be equal to or lower than that near the surface.

The rust preventive agent may be a single material or a mixture of multiple materials as in the above example. It is also possible to heat-treat. Furthermore, if an excessive amount of rust preventive agent adheres to the ferromagnetic metal thin film, it can be removed by cleaning the surface of the thin film with a solvent that selectively dissolves the rust preventive agent.

Normally, rust preventive agents are strongly adsorbed to specific locations on the surface of the ferromagnetic metal thin film in a chemically adsorbed or similar state, so they are not removed by solvent cleaning.This means that even after solvent cleaning, the rust preventive effect is sufficient. It can be inferred from the obtained facts, and can also be determined by X-ray photoelectron photoactivity (ESCA) chemical shift measurement.

As mentioned in the section on conventional examples, the rust preventive used in the present invention is
Since the effect of improving the coefficient of friction between magnetic recording media and magnetic heads, rotating cylinders, etc. is not significant, if there is a demand for even higher lubricity in magnetic recording media, it is necessary to consider combinations with various lubricants. . As a concrete means of this.

for example.

(1) A lubricant layer is formed on (outside) the ferromagnetic metal thin film around which a rust preventive agent is present.

(2) A ferromagnetic metal thin film with a rust preventive agent surrounding it on one side of a flexible long non-magnetic substrate.

A lubricant layer or a lubricant-containing resin layer may be formed on the other side. FIGS. 1 to 3 schematically show an example of the structure of the magnetic recording medium of (1) above. In the figure, 1.1', 1'' are substrates, 2, 2/, 2# are ferromagnetic metal thin films, 3.3', 3
” is the rust preventive adsorption layer, 4, 4', 4” is the lubricant layer, 6
is a ferromagnetic metal oxide layer covering the surface of the oxygen-containing ferromagnetic metal thin film layer. In the example shown in FIG. 1, the lubricant 4 is uniformly adsorbed onto the rust preventive agent 3. In the example shown in FIG. 2, the lubricant 4' is aggregated and adsorbed in the form of islands on the rust preventive agent 3'. FIG. 3 shows an example from a microscopic perspective compared to FIGS. 1 and 2, which is obtained by obliquely depositing a ferromagnetic metal in the presence of a trace amount of oxygen gas.

An example is shown in which a rust preventive adsorption layer 3' is provided on a ferromagnetic metal thin film 2' having a columnar crystal structure whose surface is coated with an oxide layer, and a lubricant layer 4'' is provided on the surface thereof. As is clear from the above, the magnetic recording medium of the present invention has good corrosion resistance because the ferromagnetic metal thin film is covered with a rust preventive adsorption layer, and with the help of the lubricant layer on the surface, the magnetic recording medium of the present invention has good corrosion resistance. The coefficient of friction is also lowered, and the wear resistance of the magnetic recording medium surface during repeated running is improved.Additionally, surprisingly, interposing a rust preventive layer is better than when a lubricant is directly adsorbed on a ferromagnetic metal thin film. The lubricant layer is composed of the lubricant described below. Antistatic agents, anti-mold agents, etc. are added as necessary to the lubricant layer. You can also do that.

As the lubricant, fatty acids, fatty acid esters, fatty acid amides, metal soaps, aliphatic alcohols, paraffins, silicones, fluorine surfactants, etc. can be used. Among these, some of them, such as fatty acids and fluorine-based surfactants, exhibit rust-preventing effects on ferromagnetic metal thin films. In the present invention, it is appropriate to use it as a lubricant because the effect is further improved compared to when it is used alone.

Fatty acids include lauric acid and myristic acid.

Valmitic acid, stearic acid, behenic acid, olein rl
Those having 12 to 22 carbon atoms such as iL, linoleic acid, and lylunic acid can be used.

Ethyl stearate is a fatty acid ester.

Butyl stearate, amyl stearate, stearic acid monoglyceride, valmitic acid monoglyceride, oleic acid monoglyceride, pentaerythritol tetrastearate, etc. can be used.

Examples of fatty acid amides include caproic acid amide, capric acid amide, lauric acid amide, valmitic acid amide, stearic acid amide, and behenic acid amide.

Oleic acid amide, linoleic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, etc. can be used.

Metallic soaps include zinc and lead such as lauric acid, myristic acid, valmitic acid, stearic acid, behenic acid, oleic acid, υnolic acid, and lylunic acid.

Salts with nickel, cobalt, iron, aluminum, macnesium, strontium, copper 1, etc.; salts with lauryl, palmityl, myristyl, stearylhhenyl, oleyl, linole, linole, etc.; salts with the various metals listed above; Can be used. As the aliphatic alcohol, cetyl alcohol, stearyl alcohol, etc. can be used. As the paraffin, saturated carbonization such as n-octadecane, n-nonadecay, n-trideca7, n-tocosan, n-todriacontane, etc. can be used. Silicones that can contain hydrogen include polysiloxanes in which hydrogen is partially substituted with an alkyl group or a phenyl group;
Those modified with fatty acids, aliphatic alcohols, acid amides, etc. can be used.

Examples of fluorine-based surfactants include fluoroalkylcalebonic acid and fluoroalkylsulfonic acid and salts such as sodium, potassium, magnesium, zinc, aluminum, iron, carbon dioxide, nickel, etc., fluoroalkyl phosphate esters, Perfluoroalkyl betaine,
Perfluoroalkyltrimethylammonium salts, barfluoroethylene oxide, perfluoroalkyl fatty acid esters, etc. can be used.

The adhesive may be used alone or as a mixture of multiple types. It is also possible to perform heat treatment after forming the lubricant layer in order to stabilize the lubricant layer.

The thickness of the lubricant layer is preferably 500 Å or less, preferably 200 Å or less. When the ferromagnetic thin film has a columnar crystal structure formed by oblique evaporation or the like.

As shown in Figure 3, a lubricant layer may be formed over the entire surface of the columnar crystal, but the effects of the present invention can also be obtained even if the lubricant is locally precipitated on the surface as shown in Figure 2. 0 In addition, in each of the above, a rust preventive agent is mixed in the lubricant layer.
It is also possible to add rust preventive agent to the ferromagnetic metal thin film.
It is also possible to further improve corrosion resistance.

Next, to explain the magnetic recording medium of (2) above,
In this case, the lubricant layer is formed by depositing each of the above lubricants alone or a mixture thereof directly on the surface of the nonmagnetic substrate or on the bank coat layer previously formed on the surface of the nonmagnetic substrate. Specifically, this is done by applying a thin layer of lubricant diluted with a solvent, or applying lubricant vapor to the surface.

It is also possible to add an antistatic agent, a fungicide, or a rust preventive agent present on the magnetic surface. The amount of lubricant attached is 0.5 to 500q per m2 of magnetic recording medium,
Preferably, 6 to 200 m9 is appropriate.

Further, as another method of forming a lubricant layer, a method of mixing a lubricant into the bank coat to form a lubricant layer can also be adopted. Specifically, carbon black.

Fine powders of graphite, molybdenum disulfide, calcium carbonate, silica, alumina, etc. are dispersed.

A solution prepared by dissolving or dispersing the lubricant in a solution of vinyl chloride, ester, urethane, epoxy, or other resin is applied to the surface of a nonmagnetic substrate.

A back coat containing lubricant is formed. In this case, the thickness of the resulting coating film is suitably 0.01 to 0.5 μm, and the lubricant content in the coating film is suitably in the range of 0.1 to 50% by volume. It is also possible to add to this back coat an antistatic agent, a fungicide, or a rust preventive agent adsorbed on the magnetic surface.

If a rust preventive agent is added to the lubricant layer, when a magnetic recording medium is wound up and the front and back sides come into contact, the rust preventive agent will be transferred to the magnetic surface along with the lubricant, and this will cause wear on the surface of the magnetic layer during actual use, and reduce magnetic properties. It can be newly adsorbed to damaged parts such as cracks that occur in the layer, thereby preventing deterioration of the corrosion resistance of that part. For the same purpose, it is also possible to leave an excess of unadsorbed rust preventive on the rust preventive adsorption layer on the surface of the magnetic layer, but if this amount is too large, it may cause head clogging. Therefore, this amount is at most 1 oomy per 1 m2 of magnetic recording medium.
is the limit, and 6 to 50 mg is desirable.

That is, within this limit, clogging can be prevented by the effect of transferring the lubricant to the magnetic surface, and this is one of the effects of the present invention.

For the purpose of perfecting the transfer of the lubricant onto the magnetic surface, the magnetic recording medium can be heat-treated in its wound state immediately after manufacturing, if necessary. The conditions in this case are, for example, 30 to 60'C for 1 to 60 hours.

Hayashi will explain a specific example.

Example 1 A CoNi alloy (Ni content: 20 wt. %) was continuously obliquely deposited (cutting the low incident angle component 30' or less) to a thickness of 100 mm under similar conditions to the one in which an oxygen-containing CoNi ferromagnetic thin film was formed on the film (sample A). Vacuum level: 5 x 10 Torr.

A sample (sample B) was prepared in which a CoNi ferromagnetic thin film containing no oxygen was formed without introducing oxygen gas. As a result of measuring the amount of oxygen in the film mainly using Auger electron spectroscopy, it was found that the average amount of oxygen in the film of sample A was a factor of 10, and that of sample B.
It was less than 1 inch. Various rust inhibitors dissolved in water, ethyl alcohol, acetone, toluene, etc. are applied to the surface of these samples and dried (coating amount is 10 to 100"li).
It was adjusted to be '/m'. ) After 60°C
190 section R0H, atmosphere, banknotes (left to stand, during which time the state of rust formation was examined by periodically taking them out and observing them under a microscope. The results are shown in Tables 1 to 6. As is clear from these tables, rust prevention The agent had a large rust-inhibiting effect on OoNi thin films containing oxygen.
The same is true for oNi thin film (Ni 10-65Wt%), Go thin film, Fe-Ni thin film, Fe-Co thin film.
Similar results were observed in thin films and the like.

Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Example 2 A polyester film with a thickness of 10 μm and a surface roughness Rmax of about 300 mm was placed along the circumference of a cylindrical can and heated to 6 x 10 Torr. A CoNi alloy (Ni content 2Qw) was melted by electron beam heating by introducing oxygen gas at a flow rate of 31/min in a vacuum.
t%) was continuously obliquely deposited (cutting the low incident angle component below 30°), and an oxygen-containing CoNi ferromagnetic thin film was formed on the film to a thickness of 100 mm (sample) under similar conditions as above. A CoNi ferromagnetic thin film containing no oxygen was prepared by vapor deposition at a vacuum degree of 6×10 Torr without introducing oxygen gas (sample B). Results of measuring oxygen in the film mainly using Auger electron spectroscopy.

The average amount of oxygen in the membrane of the sample was less than 1% of that of the original with respect to CO and N'i. Various rust preventive agents are dissolved in water, alcohol, acetone, ethyl acetate, toluene, etc. and applied to the surface of these samples, and then washed with these solvents and dried to adsorb the rust preventive agent on the sample surface. A layer was formed. A lubricant layer was formed on the surface by diluting various lubricants with a solvent and coating and drying. If an appropriate solvent does not exist, the sample surface is exposed to lubricant vapor by heating in vacuum, air, or inert gas to form a lubricant layer (applying amount is 10 to 10%). 10oq/r
(Adjusted so that it was +1".)

Then, these samples were slit to a predetermined width.

It was made into magnetic tape. These tape trials f: 50″C2
The sample A was left in an atmosphere of 90% R, H, and during that time sample A was taken out every 3 days and sample B was taken out every day, and the occurrence of head clogging was checked by recording and playing back on a video deck.
In addition, the state of rust occurrence was investigated by observing the surface of the magnetic layer side under a microscope. The results are shown in Table 7 below.) (The following is a blank space) Example 3 Using the same samples A and B used in Example 2, various rust preventives were applied to their surfaces such as ethyla-recor, acetone, and acetic acid. It was dissolved in ethyl, toluene, etc., and then applied and dried to form an adsorption layer of the rust preventive agent.

The coating amount is 1011g/r+1! I adjusted it so that it was close.

Also, on the back side (polyester film side surface).

Various lubricants were dissolved in the above solvents, applied and dried to form a lubricant layer. The coating amount was adjusted to be 10 to 100/male. Thereafter, the sample was held in a single roll at 30'C for 10 hours, and then the sample was slit into a predetermined width to form a magnetic tape. These tape samples are 60″090%
Leave it in R, H, atmosphere, during which time sample A is taken out every 3 days and sample B is taken out every 1 day, video deck recording and playback are performed to check for clogging, and the surface of the magnetic layer side is observed using a microscope. The state of rust occurrence was investigated by this method.

The results are shown in Table 8.

Note that each of the above examples relates to a CoNi-based magnetic film, but this effect can be applied to a Co thin film, a Fe-Ni thin film,
Similar results were observed in Fe--Co thin films and the like. A ferromagnetic thin film containing oxygen has a greater effect than a pure metal thin film, but this tendency is true.

Effects of the Invention As is clear from the above, the magnetic recording medium of the present invention has excellent overall durability including corrosion resistance, runnability, and head clogging. This is an improvement and has great practical value.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1, 2, and 3 are cross-sectional views showing configuration examples of magnetic recording media according to the present invention, respectively.・Substrate, 2, 2', 2
'...Ferromagnetic metal thin film, 313'#3"...
...Adsorption layer, 4.4', 4" ...Lubricant layer, 6...Oxide layer.

Claims (1)

[Scope of Claims] (1) A magnetic device characterized in that a ferromagnetic metal thin film containing oxygen is formed on a non-magnetic substrate, and a compound that suppresses ionization is present around the ferromagnetic metal thin film. recoding media. (2) Compounds that act on ionized ferromagnetic metals and suppress the water utilization of those ions are dihydric phenols, diallyl ketones, alkylphenols, naphthols, quinones, and nitrono compounds. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is one selected from oximes. (3) A thin layer of a compound that acts on the ionized ferromagnetic metal to suppress the hydration of the ions is formed on the surface of the ferromagnetic metal thin film. Magnetic recording medium (4) At least on the magnetic layer forming surface of the nonmagnetic substrate. 2. The magnetic recording medium according to claim 1, further comprising a compound that acts on the ionized ferromagnetic metal to suppress hydration of the ion. (6) forming a ferromagnetic metal thin film containing oxygen on a non-magnetic substrate, and providing a compound around the ferromagnetic metal thin film that acts on the ionized ferromagnetic metal to suppress the hydration of the ions; Furthermore, a magnetic recording medium characterized in that a lubricant is present on the ferromagnetic metal thin film. (6) A ferromagnetic metal thin film is formed on one side of a flexible long nonmagnetic substrate, and a ferromagnetic metal thin film is formed around the periphery of a compound that acts on ionized ferromagnetic metal to suppress the water utilization of the ions, and A magnetic recording medium characterized in that a lubricant-containing layer is formed on the other side.