JP2648910B2 - Magnetic recording media - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates to a magnetic recording medium, and more particularly, to improvement in durability of a so-called hard type magnetic disk, magnetic drum, and the like.

2. Description of the Related Art Prior art and its problems The magnetic recording medium used in a magnetic disk drive is generally called a magnetic disk or a disk medium, and its base structure has a donut-shaped substrate and magnetic layers usually provided on both surfaces thereof. ing.

There are two types of substrate materials of such a recording medium, for example, a hard material such as an aluminum alloy and a plastic material such as Mylar which is the same as a magnetic tape medium. Generally, the former is called a hard type magnetic disk, and the latter is called a flexible disk. In.

By the way, magnetic recording media in magnetic disk devices and magnetic drum devices, particularly hard type magnetic disks, have problems in durability and abrasion resistance against mechanical contact with a magnetic head. The medium is provided with a protective film. Conventionally, it has been known to provide an inorganic protective film or a lubricating film such as a solid lubricant as a protective film for such a medium.

Examples of the inorganic protective film include Rh, Cr (JP-B-52-18001), Ni-P (JP-B-54-33726), and R
e, Os, Ru, Ag, Au, Cu, Pt, Pd (JP-B-57-6177), Ni-Cr (JP-B-57-17292) and the like are used. On the other hand, as a solid lubricant, Inorganic or organic lubricants, for example, silicon compounds such as SiO ₂ , SiO, Si ₃ N ₄ (Japanese Patent Publication No. 54-33726), polysilicic acid or silane coupling agents such as tetrahydroxysilane, polyaminosilane, etc. JP-B-59-39809) and carbon.

However, the materials and structures of these conventional protective films provided on the magnetic layer cannot satisfy the durability, abrasion resistance, weather resistance, corrosion resistance, and the like of the medium.

Therefore, the present inventors have previously proposed that if a topcoat layer of an organic fluorine compound is provided on the carbon protective layer, the durability, abrasion resistance, weather resistance, corrosion resistance, etc. are significantly improved [ Japanese Patent Application Nos. 60-289010, 60-289011, 60-
296301, 60-296302, 60-296303, 60-29
No. 6304, a patent application filed on April 3, 1986, and a patent application filed on April 4, 1986 (1)].

However, demands for these properties are severe, and further improvement is required.

II Object of the Invention The object of the present invention is to improve the durability, abrasion resistance, weather resistance,
An object of the present invention is to provide a magnetic recording medium which is excellent in corrosion resistance and the like, has no head suction, and has extremely high reliability in practical use.

III Disclosure of the Invention Such an object is achieved by the present invention described below.

That is, the present invention has a metal thin film magnetic layer on a non-magnetic substrate, an organometallic plasma polymerized film on this, and a plasma polymerized top coat film containing C and F or Si on this. However, F or Si exists both on the surface of the plasma-polymerized top coat film and on the magnetic layer interface, and the fluorine or silicon contained in the film at a position 1/3 from the surface side of the top coat film. Average atomic ratio to carbon F / C
Or Si / C is 1.5 times or more the average atomic ratio F / C or Si / C of fluorine or silicon and carbon contained in the film at a position 1/3 from the magnetic layer side of the top coat film, A magnetic recording medium characterized in that the atomic ratio between metal atoms M and C of the organometallic plasma polymerized film is 0.05 to 1.0.

IV Specific Configuration of the Invention Hereinafter, the specific configuration of the present invention will be described in detail.
FIG. 1 shows an embodiment of the magnetic recording medium of the present invention.

The magnetic recording medium 1 of the present invention generally has an underlayer 3 on a nonmagnetic substrate 2, and usually has a nonmagnetic metal intermediate layer 4 on the underlayer 3, and a metal thin film magnetic layer 5 (hereinafter,
A magnetic layer), an organometallic plasma polymerized film 6, a carbon protective film if necessary, and a fluorine-based or silicon-based plasma-polymerized topcoat film 7 in that order.

The organometallic plasma polymerized film 6 of the present invention comprises Ar, He, H ₂ , N ₂
It can be formed by mixing a discharge plasma of a carrier gas such as that described above with an organic metal gas or a gas generated by dissolving an organic metal in an organic solvent, and bringing the mixed gas into contact with the surface of the substrate to be treated. The organometallic gases used include tin, titanium, aluminum, cobalt, iron, copper, nickel, manganese, zinc, lead, gallium, indium, mercury, magnesium, selenium, arsenic,
Any organic compound or complex salt such as gold, silver, cadmium, and germanium can be used as long as it can be polymerized by plasma.

Specific examples are as follows (R represents an organic group, and X represents hydrogen or halogen): (A) M ^I R Examples Phenyl copper, phenyl silver (B) M ^II R _O X _{2- O} (O = 1,2) Example Diethyl zinc, dimethyl zinc, methyl mercury iodide,
Methyl magnesium iodide, ethyl magnesium bromide,
Dimethylmercury, dimethylselenium, dimethylmagnesium, diethylmagnesium, diphenylmagnesium,
Dimethyl zinc, di-n-propyl zinc, di-n-butyl zinc, diphenyl zinc, diphenyl cadmium, diethyl mercury, di-n-propyl mercury, allyl ethyl mercury, diphenyl mercury, (C) M ^III R _p X _3-p (P = 1,2,3) Example Trimethylaluminum, triethylaluminum, triisobutylaluminum, trimethylgallium, trimethylindium, diethylaluminum chloride trimethylgold (D) M ^IV R _q X _4-q (q = 1,2,3 , 4) Examples tetramethyltin, di-n-butyltinmalate,
Dibutyltin diacelate, tetra-n-butyltin,
Tetraethyllead, tetramethylgermane, tetraethylgermane, diethylcyclogermanahexane, tetraphenylgermane, methylgermane, ethylgermane, n
-Propylgenman, triethylgermane, diphenylgermane, triphenylgermane, trimethylbromogermane, triethylbromogermane, triethylfluorogermane, triethylchlorogermane, dimethyldichlorogermane, methyltrichlorogermane, diethyldichlorogermane, diethyldibromogermane, diphenyl Dibromogermane, diphenyldichlorogermane, ethyltrichlorogermane, ethyltribrogermane,
n-propyltrichlorogermane, tetraethyltin,
Trimethylethyltin, tetraallyltin, tetraphenyltin, phenyltrimethyltin, triphenylmethyltin, dimethyltin dichloride, dimethyltin dihydride,
Trimethyltin hydride, Triphenyltin hydride, Tetramethyl lead, Tetra-n-propyl lead, Tetraisopropyl lead, Trimethylethyl lead, Trimethyl-n-propyl lead, Dimethyldiethyl lead, (E) ^MVI R _6-r (R = 1,2,3,4,6) Example Hexaethylgermane, Hexamethylditin, Hexaethylditin, Hexaphenylditin (F) Acetylacetone complex salt Exemple Acetylacetone Titanium, Acetylacetone Aluminum, Acetylacetone Cobalt, Acetylacetone Iron, Acetylacetone Copper , acetylacetone nickel, acetylacetone manganese Note R = organic salts, C ₁ -C ₁₀ (preferably C ₁ -C ₆₎ alkyl-C ₂ -C ₆ alkenyl (allyl) aryl (phenyl), acyloxy (maleoyl, acetyl) X = Halogen Fluorine, chlorine, odor , Iodine, In addition,
Phenylarsine oxide and the like can also be used.

In the plasma polymerization method, a discharge plasma of a carrier gas such as Ar, He, H ₂ , N _{2 and the} like are mixed with a monomer gas, and the mixed gas is brought into contact with the surface of the substrate to be processed to form a plasma polymerization film on the surface of the substrate. Is what you do.

To summarize the principle of plasma polymerization, when a gas is kept at a low pressure and an electric field is applied, the free electrons present in the gas in a small amount have a much larger intermolecular distance than normal pressure, so they are subjected to electric field acceleration and 5 to 10 eV Kinetic energy (electron temperature)
To win.

When the accelerated electrons collide with atoms or molecules, they break up the atomic orbitals and molecular orbitals and dissociate them into species that are unstable in normal conditions, such as electrons, ions, and neutral radicals.

The dissociated electrons are again subjected to electric field acceleration to dissociate other atoms and molecules, but this chain action quickly turns the gas into a highly ionized state. And this is called plasma gas.

Since gas molecules have little chance of collision with electrons, they do not absorb much energy and are kept at a temperature close to room temperature.

Thus, the kinetic energy of the electron (electron temperature)
A system in which the thermal motion (gas temperature) of molecules is separated is called low-temperature plasma, which creates a situation in which a chemical species can proceed with an additive chemical reaction such as polymerization while maintaining relatively the principle.
The present invention intends to form a plasma-polymerized film on an object to be processed by utilizing this situation. Note that since low-temperature plasma is used, there is no thermal influence on the object to be processed.

FIG. 2 shows an example of an apparatus for forming a plasma-polymerized film on the surface of an object to be processed. FIG. 2 shows a plasma polymerization apparatus using a variable frequency power supply.

In FIG. 2, a source gas is supplied to a reaction vessel R from source gas sources 511 or 512 via mass flow controllers 521 and 522, respectively. Gas source 511 or 512
When supplying different gases from the mixer 53, the gases are mixed and supplied in the mixer 53.

The source gases can each have a flow rate range of 1 to 250 ml / min.

In the reaction vessel R, the object to be processed 111 is provided with one rotary electrode 5.
Supported by 52.

Further, an electrode 551 facing the rotary electrode 552 is provided so as to sandwich the object 111 to be processed.

One electrode 551 is connected to, for example, a variable frequency power supply 54, and the other rotary electrode 552 is grounded at 8. Further, a vacuum system for evacuating the inside of the reaction vessel R is provided in the reaction vessel R, and this is an oil rotary pump 56,
It includes a liquid nitrogen trap 57, an oil diffusion pump 58, and a vacuum controller 59. These vacuum systems provide 0.01
Maintain a vacuum range of ~ 10 torr.

In operation, the inside of the reaction vessel R is first evacuated until the pressure in the reaction vessel R becomes 10 ^-3 Torr or less, and then the processing gas is supplied in a mixed state into the vessel at a predetermined flow rate.

At this time, the vacuum in the reaction vessel is controlled in the range of 0.01 to 10 Torr.

When the flow rate of the source gas is stabilized, the power is turned on.
Thus, a plasma polymerized film is formed on the object to be processed.

Note that Ar, N ₂ , He, H ₂ or the like may be used as the carrier gas.

Further, the applied current, the processing time, and the like may be set to normal conditions.

As the plasma generation source, any of microwave discharge, DC discharge, AC discharge and the like can be used in addition to high frequency discharge.

Organometallic plasma polymerized film 6 thus formed
Has a thickness of 30 to 300 °, more preferably 50 to 300 °.
If the thickness is less than 30 °, the effect of the present invention is not sufficient, and if it exceeds 300 °, the spacing loss increases, which is not preferable for practical use.

And the atomic ratio M / C of the metal atom M and the carbon atom C contained in the polymer film 6 is 0.05 to 1.0, more preferably
0.08 to 0.8.

If this value is less than 0.05, it does not contribute to the improvement of the adhesiveness, and if it exceeds 1.0, the plasma polymerized film becomes too hard, which is not practically preferable.

Since such a plasma-polymerized film 6 is a three-dimensionally developed thin film having a uniform thickness that adheres very firmly to an object to be processed (for example, the substrate 2), the medium having the plasma-polymerized film 6 is extremely durable. Rich.

As shown in FIG. 1, such an organometallic plasma polymerized film 6 is usually provided directly on a metal thin film magnetic layer 5 described later, and further contains fluorine or silicon on the plasma polymerized film 6. Plasma polymerization top coat film 7
Is provided directly or via a carbon protective film.

That is, the organometallic plasma polymerized film 6 of the present invention also serves as an intermediate layer for joining the metal thin film magnetic layer 5 and the top coat film 7 or the carbon protective film. Therefore, the strength of the joint surface in the case of the above-described laminated structure is remarkably improved. Therefore, the durability as a medium is significantly improved.

As described above, a plasma polymerization top coat film 7 containing fluorine or silicon is formed on such an organic metal plasma polymerization film 6.

The plasma polymerization top coat film 7 is formed by the same plasma polymerization method as the method for forming the organometallic plasma polymerization 6 described above. In the present invention, since the film contains the above-described predetermined element, the durability of the medium is increased. Properties, especially the durability of CSS, etc. are improved.

In order to allow the plasma polymerization top coat film 7 to contain fluorine, as a raw material gas, a gaseous carbon fluoride at normal temperature, such as tetrafluoromethane, octafluoropropane, octafluorocyclobutane, tetrafluoroethylene, is usually used because of its good operability. , Hexafluoropropylene and the like, and fluorocarbons such as fluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane and the like.

Further, in addition to these, hydrocarbons such as methane, ethane, propane, butane, pentane, ethylene,
One or more of propylene, butene, butadiene, acetylene, methylacetylene and the like may be mixed and used as a raw material gas.

Further, it can be used as a component of a raw material gas such as another fluoride, for example, boron fluoride, nitrogen fluoride, silicon fluoride or the like, mixed with the above gas.

Further, if necessary, Freon 12, Freon 13B1, Freon 22, or the like which is liquid or solid at room temperature may be used as a raw material.

If necessary, trace components such as nitrogen, oxygen, boron, and phosphorus may be added to the raw material.

As a result, boron, nitrogen,
A trace amount of oxygen, phosphorus, silicon, etc. may be contained.

When the top coat film 7 of the present invention is a fluorine-based film, the carbon content in the film is 30 to 80 at%, more preferably 30 to 60 at%.

When the carbon content exceeds 80 at%, the running friction increases.
If it is less than 30 at%, the durability will be reduced.

The atomic ratio of hydrogen / fluorine in the top coat film 7 is 0 to 1, more preferably 0 to 0.9.

 When this value exceeds 1.0, running friction increases.

When carbon and fluorine are contained in the top coat film 7 of the present invention, the atomic ratio of fluorine / carbon is 0.3 to 2,
More preferably, it is 0.5 to 1.5. When the atomic ratio is less than 0.3, the friction does not sufficiently decrease.

 If the atomic ratio exceeds 2, the durability deteriorates.

When carbon, fluorine and hydrogen are contained in the top coat film, the atomic ratio of carbon / hydrogen is preferably 2 to 8, more preferably 2.5 to 5. If the atomic ratio is less than 2, the corrosion resistance is not sufficient.

If the atomic ratio exceeds 8, the durability deteriorates,
Not preferred.

Further, the atomic ratio of hydrogen / fluorine is 0.2 to 1.0, and more preferably 0.2 to 0.9.

 When this atomic ratio is less than 0.2, durability deteriorates.

 If it exceeds 1.0, the initial friction is too large.

Further, in the present invention, the film is formed such that the atomic ratio of fluorine / carbon contained in the top coat film 7 increases as it goes toward the surface of the top coat film 7.

Specifically, the atomic ratio F / C of fluorine and carbon contained at a position 1/3 from the surface of the top coat film 7 is contained in the film at a position 1/3 from the substrate 2 side of the top coat film 7. 1.5 or more times the average atomic ratio of fluorine and carbon to be F / C, more preferably
2.0 times.

When the concentration distribution of fluorine is provided, the top coat film usually contains carbon, fluorine and hydrogen. The contents of carbon and the like in the entire film are as described above.

And the atomic ratio of fluorine / hydrogen on the surface is 1.5 to 3.0,
The atomic ratio of fluorine / hydrogen on the opposite side is 1.0 to 1.5,
Preferably, the ratio is at least 1.5.

Note that such a concentration gradient may be continuous or discontinuous.

By thus making the surface side of the top coat film 7 rich in fluorine, the durability of the medium is further improved.

Note that the distribution of fluorine / carbon in such a film may be continuous or discontinuous as described above, and in these production methods, the composition of the plasma source gas may be controlled over time.

The F / C elemental analysis of the top coat film 7 was performed by SIMS, ES
An analysis method such as CA and Auger may be used. When SIMS is used, F is usually used while performing ion etching with Ar or the like.
And C profiles are measured and calculated.

About SIMS measurement, Surface Science Basic Course Vol.3 (19
84) Surface analysis basics and applications P70 “SIMS and LAMMA” should be followed.

On the other hand, in order to contain silicon in the plasma polymerization top coat film 7, silicon hydride, tetramethylsilane, hexamethyldisilane, 1,1,3,3,5,5-hexamethylcyclotrisilazane, Tetravinylsilane,
3,3,3-trifluoropropyltrichlorosilazane, methyl-3,3,3-trifluoropropyldichlorosilane, 3,3,3
-Trifluoropropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclosiloxane,
Hexamethoxydisiloxane, hexaethoxydisiloxane, triethoxyvinylsilane, dimethylethoxyvinylsilane, trimethoxyvinylsilane, methyltrimethoxysilane, dimethoxymethylchlorosilane, dimethoxymethylsilane, trimethoxysilane, dimethylethoxysilane, trimethoxysilanol, hydroxymethyltrimethyl Silane, methoxytrimethylsilane, dimethoxydimethylsilane, ethoxytrimethoxysilane, bis (2-chloroethoxy) methylsilane, acetoxytrimethylsilane, chloromethyldimethylethoxysilane, 2-chloroethoxytrimethylsilane, ethoxytrimethylsilane, diethoxymethylsilane, Ethyltrimethoxysilane, tris (2-chloroethoxy) silane, dimethoxymeth 3,3,3-trifluoropropylsilane, 1-chloromethyl-2-chloroethoxytrimethylsilane, allyloxytrimethylsilane, ethoxydimethylvinylsilane, isopropenoxytrimethylsilane, 3-chloropropyldimethoxymethylsilane, chloromethyldichlorosilane Ethoxymethylsilane, triethoxychlorosilane, 3-chloropropyltrimethoxysilane, diethoxydimethylsilane, dimethoxy-3-mercaptopropylmethylsilane, triethoxysilane,
-Mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, diethoxymethylvinylsilane, chloromethyltriethoxysilane, tert-butoxytrimethylsilane, butyltrimethoxysilane, methyltriethoxysilane, 3- (N-methylaminopropyl ) Triethoxysilane, diethoxydivinylsilane, diethoxydiethylsilane, ethyltriethoxysilane, 2-mercaptoethyltriethoxysilane,
3-aminopropyldiethoxymethylsilane, p-chlorophenyltriethoxysilane, phenyltrimethoxysilane, 2-cyanoethyltriethoxysilane, allyltriethoxysilane, 3-chloropropyltriethoxysilane, 3-allylaminopropyltrimethoxysilane, Propyltriethoxysilane, hexatrimethoxysilane, 3-aminopropyltriethoxysilane, 3-
Methylacryloxypropyltrimethoxysilane, methyltris (2-methoxyethoxy) silane, diethoxymethylphenylsilane, p-chlorophenyltriethoxysilane, phenyltriethoxysilane, tetraallyloxysilane, tetrapropoxysilane, tetraisopropoxysilane, dimethoxy Diphenylsilane, diethoxydiphenylsilane, tetraphenoxysilane, 1,
1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, 1,1,1,3,5,5,
For example, 5-heptamethyltrisiloxane, hexaethylcyclotrisiloxane, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane, or the like is used.

Furthermore, tetrafluorosilane, hexafluorodisilane,
Compounds such as silicon and fluorine such as octafluorotrisilane can also be used.

 These may be used as a mixture.

Further, one or more of the above-described fluorocarbons, fluorohydrocarbons, and hydrocarbons may be mixed and used.

Such a silicon-based top coat film 7 has a carbon content of 5 to 50 at%. The content of silicon is silicon /
Characterized by the atomic ratio of carbon, this value is between 0.5 and 20, more preferably between 1 and 18.

When the atomic ratio is less than 0.5, the friction is not sufficiently reduced, and when it exceeds 20, the strength of the polymer film is insufficient.

The elemental analysis method and the like may be the same as in the case of the above-mentioned fluorine-containing top coat film.

The thickness of the plasma polymerized film is about 3 to 300 °.

If the thickness exceeds 300 °, the spacing loss increases, which is not preferable.

If the angle is less than 3 °, the effect of the present invention is lost. Note that the film thickness may be measured using an ellipsometer or the like.

Further, the contact angle between this top coat film and water is 60 to 13
0 °, more preferably 65-125 °. If the contact angle is less than 60 °, the initial friction is large, and is not practically usable.

Further, it is difficult to form a plasma polymerized film having a contact angle exceeding 130 °, and there is no practical necessity.

When a fluorine-based top coat film is used, this value is preferably 100 to 130 °, particularly preferably 110 to 125 °.

Such control of the film thickness may be performed by controlling the reaction time, the flow rate of the raw material gas, and the like when forming the plasma polymerized film.

When a silicon-based topcoat film is used, the surface side of the topcoat film is made silicon-rich as in the case of the above-described fluorine-based topcoat film.

And Si / C measured at a position up to 1/3 from the surface
Is set to 1.5 times or more, more preferably 2.0 times or more, of Si / C measured from the substrate side to 1/3 position.

 Thereby, the durability is improved.

The top coat film in the present invention can contain both fluorine and silicon.

The conditions for forming the top coat film of the plasma polymerization of the present invention are as follows.
It is preferable to perform it under the condition that the value of W / (FM) becomes larger than 10 ⁷ (Joule / Kg). Here, W: plasma power (Joule / sec), F: source gas flow rate (Kg / sec), and M: source gas molecular weight.

If W / (FM) is smaller than 10 ⁷ , the density of the plasma polymerized film 7 will be insufficient, and the effect of the present invention will not be sufficiently exhibited. The upper limit of W / (FM) is generally 10 ¹⁵ Joul
It is about e / Kg.

By the way, a metal thin-film magnetic layer 5 containing one or more of Co or Ni, Cr, P as a main component is provided under the above-mentioned organometallic plasma polymerized film 6.

As specific examples of the composition of this, Co-Ni, Co-Ni-
Cr, Co-Cr, Co-Ni-P, Co-Zn-P, Co-Ni-Mn-Re
-P and the like. Among these, Co-Ni, Co-Ni-C
r, Co-Cr, Co-Ni-P and the like are preferable, and the preferable composition ratio of these alloys is, by weight, Co: Ni = 1: 1 to 9: 1, _x in (Co _x Ni _y ) _A Cr _B : y = 1: 1-9: 1, A: B = 99.9-0.
1~75: 25, Co: Cr = 7: 3~9: 1, in _{(Co x Ni y) A P} B, x: y = 1: 0~1: 9, A: B = 99.9: 0.1~85 : 15. Outside these ranges, the recording characteristics deteriorate.

Such a metal thin film magnetic layer 5 can be formed by various plating methods of a gas phase or a liquid phase, and among them, a sputtering method, which is one of the gas phase methods, is particularly preferable. By using the sputtering method, a magnetic layer having good magnetic properties can be obtained.

The sputtering method can be further roughly classified into a plasma method and an ion beam method depending on the region where the operation is performed.

In a sputtering method by a plasma method, an abnormal glow discharge is generated in an inert gas atmosphere such as Ar, and a target (evaporation material) is sputtered by Ar ions.
It is deposited on the adherend.

Either DC sputtering for applying a DC voltage of several KV to the target or RF sputtering for applying a high frequency power of several hundred to several KW may be used.

In addition to the multi-polarization from two-pole to three-pole and four-pole sputtering equipment, a perpendicular electromagnetic field is applied to give cycloidal motion similar to the magnetron of electrons in the plasma, creating high-density plasma and lowering the applied voltage, May be used for the magnetron sputtering.

In the ion beam method, Ar or the like is ionized and extracted using an appropriate ion source, extracted as an ion beam toward the high vacuum side by a negative high voltage applied to the electrode, and the target material sputtered by irradiating the target surface with, for example, a coating. Deposit on the body.

Further, the kinetic energy of the adhered particles in the sputtering method is about several eV to 100 eV, for example, that of the vapor deposition method (about 0.1 eV
~ 1 eV).

In the present invention, as the material of the target, an alloy or the like corresponding to the desired composition of the metal thin-film magnetic layer 5 may be used.

Incidentally, the composition of the metal thin film magnetic layer 5 is changed to CoP or CoNiP.
In this case, the layer may be formed by a liquid phase plating method, particularly, an electroless plating method. The magnetic layer shows good magnetic properties as in the above-mentioned sputtering method.

Various known plating bath compositions and plating conditions used for electroless plating can be applied.For example, those described in Japanese Patent Publication No. 54-1936, Japanese Patent Publication No. 55-14865, etc. Both can be used.

The thickness of the metal thin film magnetic layer 5 as described above is 200 to 5
000Å, especially 500-1000Å is preferred.

Examples of the nonmagnetic substrate 2 used in the present invention include metals such as aluminum and aluminum alloys, glass, ceramics, and engineering plastics. Among these, it is preferable to use aluminum, an aluminum alloy, or the like, which has good mechanical rigidity and workability, and can easily form an underlayer described later.

The thickness of the non-magnetic substrate 2 is about 1.2 to 1.9 mm, and its shape is not particularly limited, such as a disk shape or a drum shape.

When a metal substrate such as Al is used as the material of the non-magnetic substrate 2, it is preferable to provide the underlayer 3 on the substrate. This underlayer 3 is made of Ni-P, Ni-Cu-
It is formed containing any composition such as P, Ni-WP and Ni-B. This is preferably formed by a liquid phase plating method, particularly an electroless plating method. According to the electroless plating method, an extremely dense film can be formed, and mechanical rigidity, hardness, and workability can be improved.

The composition ratio (wt) of the underlayer having the above composition is as follows:
It is as follows.

That, (NixCuy) _A P _B, in the case of these (NixWy) _A P _B is, x: y = 100: 0~10 : 90, A: B = 97: 3~85: a 15.

 In the case of NixBy, x: y = 97: 3 to 90: 3.

To briefly describe an example of the process of the electroless plating method, first, after performing alkaline degreasing and acidic degreasing,
The zincate treatment may be repeated several times, and the surface may be adjusted with sodium bicarbonate or the like, followed by plating in a nickel plating bath having a pH of 4.0 to 6.0 at about 80 to 95 ° C. for about 0.5 to 3 hours.

These plating processes are described in, for example, Japanese Patent Publication No. 48-18842 and Japanese Patent Publication No. 50-1438.

The thickness of the underlayer 3 is 3 to 50 μm, particularly 5 to 20 μm.
μm is preferred.

Further, it is preferable to provide an uneven portion on the surface of the underlayer 3.

In order to form the irregularities, for example, an abrasive is applied while rotating the disk-shaped substrate 2 on which the base layer 3 is provided,
Concentric irregular grooves are provided on the surface of the underlayer 3.

Note that the uneven portions may be provided randomly on the base layer 3.

By providing such an uneven portion, the adsorption characteristics and the durability are improved.

When the base layer 3 is not provided on the base 2, the above irregularities may be provided directly on the base 2.

Further, the metal thin-film magnetic layer 5 described above is provided on a substrate that may have such an underlayer 3.

When such a metal thin-film magnetic layer 5 is formed by the sputtering method as described above, a space between the underlayer 3 and the magnetic layer 5 is formed.
It is preferable to provide a specific magnetic metal intermediate layer 4 containing Cr.
By providing the nonmagnetic metal intermediate layer 4, the magnetic properties of the medium are improved, and the reliability of the recording properties can be improved.

The nonmagnetic metal intermediate layer 4 is usually most preferably formed of Cr, but the Cr content may be 99 wt% or more.

The intermediate layer 4 can be formed by various known vapor-phase film forming methods. However, it is usually preferable to form the intermediate layer 4 by a sputtering method as in the case of the metal thin-film magnetic layer 5 described above. The thickness of the non-magnetic metal intermediate layer 4 should be appropriately determined depending on the type of the metal thin-film magnetic layer 5 to be used.
About Å.

The magnetic recording medium 1 of the present invention comprises the above-described metal thin film magnetic layer 5.
A non-magnetic metal protective film such as Cr may be provided between the organic metal plasma polymerized film 6 and the organic metal plasma polymerized film 6.

The method for forming the nonmagnetic metal protective film 6 may be the same as that for the nonmagnetic metal intermediate layer 4 described above.

Further, a carbon protective film is formed on the organic metal plasma polymerized film
It is preferred to form a layer directly on the substrate.

By providing the carbon protective film, the durability and weather resistance are further improved.

The carbon protective film is composed of C alone as its composition, but may contain other elements in an amount of less than 5 wt%.

The carbon protective film can be formed by various vapor phase film forming methods such as a sputtering method, an ion plating method, a vapor deposition method, and a CVD method, and among them, the sputtering method is particularly preferable. In this case, the formed film becomes extremely dense, and has an effect more excellent in durability and weather resistance.

The thickness of the carbon protective film formed as a more preferred embodiment in this manner is preferably 10 to 800, more preferably 100 to 400.

Further, when forming the organic plasma polymerized film,
Plasma treatment can be performed in advance.

The magnetic recording medium 1 as described above may be a single-sided recording medium as shown in FIG. 1, but a so-called double-sided recording in which magnetic layers and the like are provided on both sides of a base 2 in the same manner as in FIG. Medium.

V According to the present invention, a plasma polymerized top coat film containing fluorine or silicon is provided on a metal thin film magnetic layer via an organometallic plasma polymerized film.

Therefore, the obtained medium is excellent in durability, abrasion resistance, weather resistance, corrosion resistance and the like, and has extremely high reliability in practical use.

VI Specific Examples of the Invention Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

(Example 1) A NiP underlayer 3 having a thickness of 20 µm was provided on a disk-shaped Al substrate 2 having a diameter of 13 cm and a thickness of 1.9 mm by an electroless plating method.
The electroless plating was performed under the following process and manufacturing conditions.

(NiP electroless plating) The underlayer 3 had a composition of Ni: P = 85: 15 (weight ratio) and a thickness of 20 μm.

In addition to the Al base 2 having the NiP underlayer 3,
As shown in Table 1, substrates 2 of various materials such as Al, glass (manufactured by Corning) and plastic (polyetherimide resin) were also used.

Next, the surface of the above-mentioned various substrates 2 (the surface of the underlayer 3 having the underlayer 3 on the substrate surface) was polished under the following conditions.

<Surface polishing treatment> Using a polishing liquid of Fujimi Polishing Co., Ltd., Mediball No. 8 (50% diluting liquid) while applying a load of 100 g while rotating the above substrate using a magnetic disk lapping machine. Polishing was performed for 10 minutes.

Thereafter, cleaning was performed using a disk substrate cleaning apparatus. The steps are as follows.

<Cleaning process> 1. Neutral detergent solution, immersion, ultrasonic 2. Ultra pure water, scrub 3. Ultra pure water, scrub 4. Ultra pure water, immersion, ultrasonic 5. Ultra pure water, immersion 6. Freon / Ethanol mixed solution, immersion, ultrasonic wave 7. Freon / ethanol mixed solution, immersion 8. Freon / ethanol, steam (→ drying) After such a washing step, the surface of the substrate 2 The surface of the underlayer 3) was provided with an uneven portion as follows (hereinafter referred to as a texturing step). That is, concentric irregular grooves were formed on the surface of the substrate while rotating the substrate using a tape polishing machine. The process conditions are polishing tape count # 4000, contact pressure 1.2Kg / cm ² , oscillation 50
Times / minute and the number of rotations of the work was 150 times / minute.

Thereafter, after the same cleaning as described above, a nonmagnetic magnetic metal intermediate layer 4 made of Cr was formed to a thickness of 2000 mm by sputtering.

The layering conditions were an Ar gas pressure of 2.0 Pa and a DC of 8 KW. Before the formation of the intermediate layer 4, an etching treatment was performed under the conditions of an Ar gas pressure of 0.2 Pa and RF of 400 W.

Thereafter, various metal thin-film magnetic layers 5 as described below were successively provided thereon. When the magnetic layer was formed by the electroless plating method, the above-mentioned etching treatment was not performed, and the nonmagnetic metal intermediate layer 4 made of Cr was not provided.

<Formation of Metal Thin Film Magnetic Layer> A magnetic layer No. 1 CoNi magnetic layer was formed by a sputtering method. The deposition conditions were an Ar gas pressure of 2.0 Pa and a DC of 8 KW. CoNi composition weight ratio is Co / N
i = 80/20 and the film thickness was 600 °.

Magnetic Layer A No. 2 CoNiCr magnetic layer was formed by a sputtering method. The deposition conditions were an Ar gas pressure of 2.0 Pa and a DC of 8 KW.

The CoNiCr composition weight ratio was 62.5: 30: 7.5, and the film thickness was 600 °.

Magnetic Layer A No. 3 CoCr magnetic layer was formed by a sputtering method. The deposition conditions were an Ar gas pressure of 2.0 Pa and a DC of 8 KW.

The composition weight ratio of CoCr was Co / Cr = 87/13, and the film thickness was 1000 °.

Magnetic Layer A No. 4 CoNiP magnetic layer was formed by using an electroless plating method. CoN
The composition weight ratio of iP was Co: Ni: P = 6: 4: 1, and the film thickness was 1000 °.

The electroless plating process and manufacturing conditions were as follows.

An organometallic plasma polymerized film was formed on the various metal thin film magnetic layers thus formed by using the same apparatus as in FIG. 2 under the plasma polymerization conditions shown below.

Organometallic plasma polymerized film 1 Monomer gas: Tetramethyltin Monomer gas flow rate: 10 ml / min Carrier gas: Argon Carrier gas flow rate: 50 ml / min Vacuum: 0.5 Torr High frequency power supply: 13.56 MHz, 200 W It was confirmed to be a polymer thin film containing tin by measuring with a Fourier transform infrared spectrophotometer and ESCA.

Metal / C (M / C) = 0.35 Organometallic Plasma Polymerized Film 2 Under the same conditions as in Example 1, a polymerized film was produced using acetylacetone titanium as a monomer.

 The film thickness was 210 °.

M / C = 0.21 Organometallic Plasma Polymerized Film 3 Under the same conditions as in Example 1, a polymerized film was formed using dimethylmagnesium as a monomer.

 The film thickness was 250 °.

M / C = 0.31 Organometallic Plasma Polymerized Film 4 Under the same conditions as in Example 1, a polymerized film was formed using phenyl copper as a monomer.

 The film thickness was 280 °.

M / C = 0.19 Organometallic plasma polymerized film 5 Under the same conditions as in Example 1, a polymerized film was formed using dimethylzinc as a monomer.

 The film thickness was 200 °.

M / C = 1.1 Organometallic Plasma Polymerized Film 6 Under the same conditions as in Example 1, a polymerized film was formed using trimethylaluminum as a monomer.

 The film thickness was 250 °.

M / C = 0.10 Organometallic plasma polymerized film 7 Under the same conditions as in Example 1, a polymerized film was formed using tetraethyltin as a monomer.

 The thickness was 300 °.

M / C = 0.21 Organometallic Plasma Polymerized Film 8 Under the same conditions as in Example 1, a polymerized film was formed using phenylsilver as a monomer.

 The film thickness was 250 °.

M / C = 0.04 Organometallic Plasma Polymerized Film 9 (Comparative) Under the same conditions as in Example 1, a polymerized film was produced using C ₂ H ₄ as a monomer.

 The thickness was 300 °.

Further, a plasma-polymerized top coat film 7 was formed thereon under the following conditions.

That is, as shown in FIG. 2, the object to be processed was placed in a vacuum chamber, and was once evacuated to 10 ^-3 Torr. Then, a predetermined raw material gas shown in Table 1 below was introduced thereinto, and then 13.56M while maintaining the gas pressure at 0.05 torr.
Plasma was generated by applying a high frequency voltage of Hz to prepare various samples having a predetermined plasma polymerized film.

 The following characteristics were measured for these samples.

For sample No. 22, a carbon protective film was further formed on the organometallic plasma polymerized film to a thickness of 100 mm by a sputtering method. For sample No. 23, the surface of the magnetic layer was plasma-treated before forming the organometallic plasma polymerized film.

Plasma conditions are processing gas N ₂ , pressure 5Pa, power supply is 13.56MHZ
The frequency was set to z and the input power was set to 3KW.

(1) CSS resistance characteristics Immediately after the magnetic disk sample was created and after 40,000 times of CSS (contact start and stop) and 10
Measure the number of errors per disk recording surface after 10,000 times
An increase in the number of errors (number of missing pulses) before and after is displayed [unit: bits / plane].

The number of errors per recording surface of the disk was measured with a magnetic disk surfer, and the setting condition was that the slice level of the missing pulse was 60%.

(2) Coefficient of friction CSS (contact start and stop) 4
After 10,000 cycles, with the head still in contact, 20 ° C, 60% RH
After being left for 3 days in the above environment, the friction coefficient of the surface of the magnetic disk sample was measured.

 The head used was a Mn-Zn ferrite head.

(3) Observation of Medium Surface The surface after the CSS test was observed with an electron microscope SEM image.

 The degree of scratches on the surface was evaluated by ◎, △, Δ, and ×.

◎: No scratches at all ○: Scratch only at the surface of the top coat layer △: Scratch at the surface of the protective film ×: Scratches deeply to the protective film and the magnetic film Included The results are shown in Table 1.

In addition, x in the item of Table 1 is 1/3 from the surface of the top coat film.
Or Si / C average atomic ratio (F or Si / C) measured in
u to the average atomic ratio of F or Si / C (F or Si / C) 1 measured at a position 1/3 from the substrate side of the top coat film (F or Si / C) u / (F Or Si / C) l.

(F or sSi / H) _u and (F or Si / H) _l of the sample of the present invention are 1.5 to 3.0 and 1.0 to 1.0, respectively.
1.5.

The results of Table 1 clearly show the effect of the present invention. That is, according to the present invention, even after CSS, the number of errors is extremely small, μ is below the allowable value of 0.25, and the surface flaw is also extremely small.

[Brief description of the drawings]

 FIG. 1 is a sectional view of a magnetic recording medium according to the present invention. FIG. 2 is a schematic diagram of a plasma polymerization apparatus. BRIEF DESCRIPTION OF THE SYMBOLS 1 ... magnetic recording medium, 2 ... nonmagnetic substrate, 3 ... underlayer, 4 ... nonmagnetic metal intermediate layer, 5 ... metal thin film magnetic layer, 6 ... organic metal plasma polymerized film 7: Plasma-polymerized top coat film 53: Mixer, 54: DC, AC and variable frequency power supply, 56: Oil rotary pump, 57: Liquid nitrogen truck, 58: Oil diffusion pump, 59: ... Vacuum controller, 111 ... Workpiece, 511,512 ... Material gas source, 521,522 ... Mass flow controller, 551,552 ... Electrode

Continued on the front page (72) Inventor Fumio Maruta 1-1-13 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Kunihiro Ueda 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (56) References JP-A-61-22426 (JP, A) JP-A-57-135442 (JP, A)

Claims (14)

(57) [Claims] A metal thin film magnetic layer on a non-magnetic substrate,
An organic metal plasma polymerized film is formed thereon, and a plasma polymerized top coat film containing C and F or Si is formed thereon. F or Si is present, the average atomic ratio F / C or Si / C of fluorine or silicon and carbon contained in the film at a position 1/3 from the surface side of the top coat film is The average atomic ratio of fluorine or silicon and carbon contained in the film at a position 1/3 from the magnetic layer side is not less than 1.5 times the average atomic ratio F / C or Si / C, and the metal atoms of the organometallic plasma polymerized film A magnetic recording medium, wherein the atomic ratio of M to C is 0.05 to 1.0. 2. The top coat film contains H, and the F / H or Si / H of the surface portion of the top coat film is 1.5 to 3.0, and the F / H or Si / H of the interface portion on the magnetic layer side is 1.0 to 1.5. The magnetic recording medium according to claim 1. 3. The magnetic layer of a metal thin film is made of Co, or Co and Ni, Cr, P
Claim 1 comprising at least one of the following as a main component:
Item 3. The magnetic recording medium according to item 2 or 2. 4. The thickness of the organometallic plasma polymerized film is 30 to 300.
The magnetic recording medium according to any one of claims 1 to 3, wherein Å. 5. The method according to claim 1, wherein the top coat film is C and F or C, F.
5. The magnetic recording medium according to claim 1, wherein the magnetic recording medium contains H and H, and has an average C content of 30 to 80 at%. 6. The magnetic recording medium according to claim 1, wherein the top coat film contains C and Si, and has an average C content of 5 to 50 at%. 7. The magnetic recording medium according to claim 1, wherein the thickness of the top coat film is 3 to 300 °. 8. The magnetic recording medium according to claim 1, further comprising an underlayer between the base and the metal thin film magnetic layer. 9. The magnetic recording medium according to claim 1, further comprising a nonmagnetic metal intermediate layer in contact with the magnetic layer on the base side of the metal thin film magnetic layer. 10. The magnetic recording medium according to claim 1, further comprising a non-magnetic metal protective film between the metal thin film magnetic layer and the organometallic plasma polymerized film. 11. The magnetic recording medium according to claim 1, wherein a carbon protective film is provided between the organometallic plasma polymerized film and the plasma polymerized top coat film. 12. The magnetic recording medium according to claim 7, wherein the surface of the underlayer has irregularities. 13. The magnetic recording medium according to claim 1, wherein the nonmagnetic substrate is a rigid substrate. 14. The magnetic recording medium according to claim 1, wherein said magnetic recording medium has a disk shape.