JPH0449522A - Magnetic disk, its production and production device - Google Patents

Abstract

PURPOSE:To prevent spin-off of a lubricant layer caused by rotation of the disk by using a fluorine-base polar lubricant layer having hydrophilic functional groups in the structural molecule and applying this lubricant layer on the surface of a protective film layer which is reformed into hydrophilic. CONSTITUTION:Since the protective film essentially comprising carbon, the surface which is reformed into hydrophilic, generates large interaction with a fluorine-base polar lubricant having hydrophilic functional groups, the fluorine- base polar lubricant is strongly held on the carbon protective film. As a result, splashing or evaporation of the lubricant is hardly caused and the lubricant layer can maintain its thickness and has enough mechanical durability and water repellent property. The magnetic disk consists of a nonmagnetic substrate 1 comprising an aluminum alloy, Ni-P plating base layer 2, Co-Ni-Cr alloy magnetic layer 3, protective film 5 essentially comprising carbon and having hydrophilic surface, which is the feature of this invention, and a fluorine-base polar lubricant layer 6 having hydrophilic functional groups in the structural molecules, as shown in the partial cross section of this magnetic disk. Number 4 in the cross section is a so-called magnetic disk substrate. As for the lubricant, KRYTOX 157FS(M) is applied by dip coating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk. More specifically, the present invention relates to a magnetic recording medium on which a protective film and a lubricant layer are formed to improve durability and reliability, a method for manufacturing the same, and an apparatus for manufacturing the same.

[Prior Art] In recent years, the importance of external storage devices such as magnetic disks in computer systems has increased, and with this, the demand for higher recording densities in magnetic recording devices using magnetic disks and the like has increased. ing.

Such a magnetic recording device is composed of the main components of a recording/reproducing head and a magnetic disk, and the magnetic disk rotates at high speed, while the recording/reproducing head is placed at a position a minute distance from the surface of the magnetic disk. ing. In order to improve the performance of magnetic recording devices by reducing this minute interval, the load on the recording/reproducing head is reduced, and contact start/stop (08
8)) type head floating system is adopted.

In order to increase the recording density and performance of magnetic disks, it is necessary to make the magnetic recording medium thinner, more uniform, and improve its magnetic properties, as well as to ensure a stable head flying state at a low flying height. Furthermore, it is necessary to improve the accuracy of the roughness of the disk surface in order to prevent collisions between the head and the disk (head crash), and to improve the head crush resistance.

However, with the improvement of the accuracy of the roughness of the disk surface, for example, Journal of the Japan Society of Applied Magnetics, Vol. 10, No. 1,
As described in No. 11 (198B), the coefficient of kinetic friction during sliding contact between the magnetic disk and the magnetic head becomes significantly large, resulting in a drawback that the sliding characteristics until the head flies are deteriorated.

Conventional magnetic disks are manufactured by forming a layer of Fe oxide on a resin film substrate, aluminum alloy substrate, or N1-Cu-P alloy substrate by reactive sputtering using Pe and oxygen. , a magnetic layer made of γ-pe203 is formed by further oxidation in the air, a base layer of N1-P alloy is formed on the aluminum alloy substrate by plating method, and then an N1-Do-P alloy is formed on the base layer of N1-P alloy by plating method. A magnetic layer formed by a plating method is known.

However, such a magnetic disk has a drawback that its sliding characteristics with the above-mentioned magnetic head are poor, resulting in damage to the magnetic disk or magnetic head and poor mechanical durability.

In order to eliminate these drawbacks and protect the underlayer and magnetic layer of the magnetic disk, sputtering, electron beam evaporation, or vapor phase chemical vapor deposition has conventionally been applied on the magnetic layer.
A lubricating film is formed by forming a protective film made of carbon by a vapor deposition (CVD) method, or by applying a fluorine-based lubricant thereon by a spin cord method, a dip coating method, or the like. The above-mentioned prior art is described in Japanese Journal of Applied Magnetics, vol. 10. No. 1, p. B (19811
t) etc.

[Problems to be Solved by the Invention] However, in conventional magnetic disks having a protective film made of carbon, it is difficult to retain the fluorine-based lubricant coated on the carbon protective film, and as the magnetic disk rotates, the fluorine lubricant The fluorine-based lubricant may scatter, or the fluorine-based lubricant may evaporate depending on the length of time and temperature it is left on, reducing the lubricating effect of the protective layer on the magnetic head, and causing damage to the magnetic disk and magnetic head. There is a problem that sufficient durability and reliability cannot be achieved. In addition, regarding the above phenomenon, E., E. France and B., Bhushan;
d B, Bhushan; ASLE 5P-20 (
1985)).

The present invention has been made to solve such conventional problems, and consists of forming a protective film mainly made of carbon on the magnetic layer, and subjecting the outermost surface to plasma treatment with a gas such as 02, N2, etc., and irradiation with ultraviolet rays. The surface of the protective film is modified to be hydrophilic by treatment, ozone treatment, ion bombardment treatment, reverse sputtering treatment, etc., and then a fluorine-based polar lubricant having hydrophilic functional groups in the molecule is applied to improve lubrication. Our primary objective is to provide a magnetic disk with almost no scattering or evaporation phenomena of the agent, resulting in no reduction in playback output, and which has sufficient durability and corrosion resistance for practical use, and in order to manufacture it. The second and third objects of the present invention are to provide an improved method of manufacturing a magnetic disk and an apparatus for manufacturing the same.

[Means for Solving the Problems] A first object of the present invention is to provide a substrate having a non-magnetic base and a magnetic layer, a protective film mainly made of carbon formed on the magnetic layer, and a fluorine-based polar lubricant. A magnetic disk comprising a layer, wherein the fluorine-based polar lubricant layer has a hydrophilic functional group in its constituent molecules, and the fluorine-based polar lubricant layer is disposed on the surface of the protective film layer that has been improved in hydrophilicity. This is achieved by a magnetic disk formed by coating.

That is, according to the present invention, for example, N1
It has a hardened base layer such as -P, and further has a Co-Ni layer on top of it.
- A substrate having a metal magnetic layer such as Cr, on which a protective film layer mainly made of carbon is formed, is placed on a sample stage provided in a high frequency plasma processing chamber, and After evacuating to a high vacuum, oxygen gas (
02), nitrogen gas (N2), ammonia gas (NH3)
), water vapor (N20), carbon oxide gas (CO), and carbon dioxide gas (CO2), at a gas pressure of 1 to 1000 mTorr, preferably 10 to 700 mTorr.

More preferably, the surface of the protective film is subjected to plasma treatment at a discharge power of 100 to 500 s Torr and a discharge power of 2 to 200 V, preferably 5 to 100 W, and even more preferably 7 to 50 W, and then a carboxyl group, an amino group, a hydroxyl group, A magnetic disk characterized in that it is formed by coating a fluorine-based polar lubricant having a hydrophilic functional group such as a silanol group, a sulfonic acid group, or a phosphoric acid group in its constituent molecules is provided.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate, and a protective film layer mainly made of carbon formed on the metal magnetic layer is mounted on a sample stand installed in an ultraviolet irradiation device. After the chamber is evacuated, at least one type of gas selected from among the gases is introduced into the chamber, and the gas pressure is 1 to 500 Torr, preferably 10 to 50 Torr.
450 Torr s, more preferably 200 to 400 T
orr to irradiate the surface of the protective film with ultraviolet rays, and then add hydrophilic functional groups such as carboxyl groups, amino groups, hydroxyl groups, silanol groups, sulfonic acid groups, phosphoric acid groups, etc. to the protective film within the constituent molecules. Provided is a magnetic disk characterized in that it is coated with a fluorine polar lubricant having the following properties.

Furthermore, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer is placed in a container having an ozone generator. The substrate is placed on the provided sample stand, the ozone generator generates ozone, the substrate is exposed to ozone, and then carboxyl groups, amino groups, hydroxyl groups, silanol groups, and sulfonic acid groups are formed on the protective film. A magnetic disk characterized in that it is coated with a fluorine-based polar lubricant having a hydrophilic functional group such as a phosphoric acid group or a phosphoric acid group in its constituent molecules is provided.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer is provided in a vacuum container having an ion gun. Place the sample on a sample stand with a pressure of O, (11" 100aTorr) using nitrogen gas or argon gas.
Preferably, an ion flow is generated from the ion gun under (1,1 to 1[lOmTorr, more preferably 1 to 5OmTorr), and the surface of the protective film is subjected to ion bombardment treatment, and then a carboxyl group is formed on the protective film. A magnetic disk characterized in that it is formed by coating a fluorine-based polar lubricant having hydrophilic functional groups such as amino groups, hydroxyl groups, silanol groups, sulfonic acid groups, and phosphoric acid groups in its constituent molecules.

Furthermore, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate, and a protective film layer mainly composed of carbon formed on the metal magnetic layer is used as a sample provided in a sputtering vacuum chamber. After placing it on a table and evacuating the chamber to a high vacuum, argon gas (^''), 02, Nz, NH3
, N20 S00% CO2, and the gas pressure is 1 to 100 s Tor.
After the surface of the protective film is reverse sputtered under preferably 1 to 70 Torr and more preferably 1 to 50 Torr, carboxyl groups, amino groups, hydroxyl groups, silanol groups, sulfonic acid groups, and phosphoric acid groups are added to the protective film. A magnetic disk characterized in that it is coated with a fluorine-based polar lubricant having hydrophilic functional groups such as , etc. in its constituent molecules is provided.

A second object of the present invention is to fabricate a substrate having a magnetic layer on a non-magnetic substrate, form a protective film on the magnetic layer, modify the surface of the protective film to be hydrophilic, and then This is achieved by a method for manufacturing a magnetic disk characterized by coating a fluorine-based polar lubricant having a group in its constituent molecules.

That is, according to the present invention, a substrate having a metal magnetic layer as described above on a nonmagnetic substrate, and a protective film layer mainly composed of carbon is formed on the metal magnetic layer, is provided in a high frequency plasma processing chamber. After placing the sample on the sample stage and evacuating the chamber to a high vacuum, 02, N2, NH3, N
20, CO1CO2, and plasma-treat the surface of the protective film under a gas pressure of 1 to 1000m100O, preferably 10 to 700filTorr, more preferably 100 to 500mTorr, and then perform plasma treatment on the surface of the protective film. A magnetic material characterized by coating a film with a fluorine-based polar lubricant having hydrophilic functional groups such as a carboxyl group, an amino group, a hydroxyl group, a silanol group, a sulfonic acid group, and a phosphoric acid group in its constituent molecules. A method of manufacturing a disc is provided.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon on the metal magnetic layer is provided in an ultraviolet irradiation device. After the chamber is evacuated, at least one gas selected from the gases is introduced into the chamber, the surface of the protective film is irradiated with ultraviolet rays, and then the surface of the protective film is irradiated with ultraviolet rays. Production of a magnetic disk characterized in that a fluorine-based polar lubricant having a hydrophilic functional group such as a carboxyl group, an amino group, a hydroxyl group, a silanol group, a sulfonic acid group, or a phosphoric acid group in its constituent molecules is formed on the magnetic disk. A method is provided.

Furthermore, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer is placed in a container having an ozone generator. The substrate is placed on a provided sample stage, the ozone generator generates ozone, and the substrate is exposed to ozone. Thereafter, a fluorine-based polar lubricant having hydrophilic functional groups such as a carboxyl group, an amino group, a hydroxyl group, a silanol group, a sulfonic acid group, and a phosphoric acid group in its constituent molecules was formed on the protective film. A method of manufacturing a magnetic disk with features is provided.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer is placed in a vacuum container equipped with an ion gun. After the chamber is evacuated to a high vacuum, a pressure of 0.01 to 100III Torr, preferably 0.1 to 1
00 mTorr, more preferably 1 to 50 mTorr
After the surface of the protective film is subjected to ion bombardment treatment, the protective film has a hydrophilic functional group such as a carboxyl group, an amino group, a hydroxyl group, a silanol group, a sulfonic acid group, a phosphoric acid group, etc. in its constituent molecules. A method for manufacturing a magnetic disk characterized in that it is formed by coating a fluorine polar lubricant is provided.

Furthermore, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer is provided in a vacuum layer of a sputtering apparatus. After evacuating the chamber to a high vacuum, Ars 02, N2, NH
At least one type of gas selected from s, N20, Co, and CO2 is introduced, and the gas pressure is 1 to 1000 m10.
The surface of the protective film is reverse sputtered under 000 Torr, preferably 1 to 500 Torr, and more preferably 1 to 50 mTorr, and then a carboxyl group,
A method for producing a magnetic disk is provided, which comprises coating a fluorine-based polar lubricant having hydrophilic functional groups such as amino groups, hydroxyl groups, silanol groups, sulfonic acid groups, and phosphoric acid groups in its constituent molecules. Ru.

A third object of the present invention is to provide a sample comprising an airtight container, a negative pressure generator capable of making the container negative pressure, a non-magnetic substrate and a magnetic layer, and a substrate on which a protective film is placed. This is achieved by a magnetic disk manufacturing apparatus comprising a stand, a reactive gas supply device, and a reactive gas excitation device, and is configured to be able to modify the surface of the protective film to be hydrophilic. .

That is, according to the present invention, a substrate having a metal magnetic layer as described above on a nonmagnetic substrate, and a protective film layer mainly composed of carbon is formed on the metal magnetic layer, is provided in a high frequency plasma processing chamber. It can be placed on the sample stage, and 02,
At least one type of gas selected from N2, NI+3, N20, CO%C02 is introduced, and the gas pressure is 1.
-1000m100O preferably lO~700mTor
rs More preferably, a magnetic disk manufacturing apparatus characterized in that the surface of the protective film of the substrate can be improved to be hydrophilic by subjecting the surface of the protective film to plasma treatment under 100 to 500 rA Torr. is provided.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer can be manufactured without breaking the vacuum. It can be placed on a sample stage provided in a high frequency plasma processing chamber, and 02, N2, NH3,820, Co
, CO2, and the gas pressure is 1 to 1000 mTorr, preferably 10 to 700 mTorr, and more preferably 100 to 50 mTorr.
A magnetic disk manufacturing apparatus characterized in that the structure is such that the surface of the protective film can be continuously improved to be hydrophilic after the protective film is formed by subjecting the surface of the protective film to plasma treatment under 0a+Torr. is provided.

Furthermore, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer can be manufactured without breaking the vacuum. , the protective film can be formed by introducing at least one type of gas selected from the gases into the chamber and irradiating the surface of the protective film layer with ultraviolet rays; Then, there is provided a magnetic disk manufacturing apparatus characterized in that the structure is such that the surface of the protective film can be continuously improved to be hydrophilic.

Further, according to the present invention, a substrate having a metal magnetic layer as described above on a non-magnetic substrate and a protective film layer mainly made of carbon formed on the metal magnetic layer can be manufactured without breaking the vacuum. The sample can be placed on the east side provided in the high frequency sputtering chamber, and Ars 02, N2, NHs, H
At least one type of gas selected from 2Os Co and CO2 is introduced, and the gas pressure is 1 to 1000 iTorr.
Preferably 1 to 500 mTorr, more preferably 1
The magnetic material is characterized in that the surface of the protective film can be continuously improved to be hydrophilic after the protective film is formed by subjecting the surface of the protective film to reverse sputtering under ~50 Torr. A disc manufacturing apparatus is provided.

Treatment methods for modifying the surface of the protective film to be hydrophilic for use in the present invention include plasma treatment, ultraviolet irradiation treatment, ozone treatment, ion bombardment treatment, reverse sputtering treatment, etc., as described above. Among these, plasma treatment, ozone treatment, ion bombardment treatment, and reverse sputtering treatment are preferred in that they are highly effective in modifying the surface of the protective film to make it hydrophilic. Furthermore, plasma treatment and reverse sputtering treatment are preferable in that they have a large interaction with the fluorine-based polar lubricant.

As described below, examples of the reactive gas excitation device include those using a high frequency electrode, those using an ultraviolet light source, and those using an ion gun.

Examples of the non-magnetic substrate include one made of any kind of non-magnetic substrate selected from the group consisting of aluminum alloy, stainless steel alloy, stainless steel, ceramics, plastic, and glass. Among these, aluminum alloy, plastic, and ceramic are preferable in terms of surface accuracy, cost, weight, and strength.

Instead of the metal magnetic layer, a magnetic film made of metal oxide, metal nitride, or a composite thereof may be used. Among these, metal magnetic layers are preferred from the viewpoint of recording density, and metal oxides and metal nitrides are preferred from the viewpoint of durability.

[Function] In the present invention, the protective film mainly composed of carbon whose surface has been modified to be hydrophilic has a strong interaction with the fluorine-based polar lubricant molecules having hydrophilic functional groups. The polar lubricant is strongly retained on the carbon protective film, resulting in almost no scattering or evaporation of the lubricant molecules, the lubricant layer does not become thinner, and has sufficient mechanical durability and It is considered to have water repellency.

[Example code] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partial sectional view of a magnetic disk showing an embodiment of the present invention, in which (1) shows a non-magnetic substrate made of an aluminum alloy, (a shows an N1-P plating underlayer formed thereon, 3) is a Co-Ni-Cr alloy magnetic layer formed thereon, (4) is a so-called magnetic disk substrate, and (5) is mainly made of carbon whose surface has been modified to be hydrophilic, which is a characteristic feature of the present invention. The protective film (6) is a fluorine-based polar lubricant layer having a hydrophilic functional group in its constituent molecules, and is coated with KRYTOX 157FSM, which will be described later, by a dip coating method.

Hereinafter, FIG. 2 shows a plasma CVD process for carrying out the present invention.
A schematic explanatory diagram showing an example of an apparatus, FIG. 3 is a schematic explanatory diagram showing an example of an ultraviolet irradiation apparatus for carrying out the present invention,
FIG. 4 is a schematic explanatory diagram showing an example of an ozone treatment apparatus for implementing the present invention, FIG. 5 is a schematic explanatory diagram showing an example of an ion bombardment apparatus for implementing the present invention, and FIG. 7 is a schematic explanatory diagram showing an example of a sputtering apparatus capable of continuous processing for carrying out the present invention. FIG. 8 is a schematic explanatory diagram showing an example of a plasma CVD apparatus capable of continuous processing for carrying out the present invention. FIG. 9 is a characteristic curve diagram showing the relationship between various modification treatment times and changes in the contact angle of the carbon protective film surface, showing an example of the invention. Characteristic curve diagram showing the relationship between the spin-off test period and the change in lubricant layer thickness when l
The figure shows an example of the present invention with a lubricant coating concentration of 7 g/l.
FIG. 11 is a characteristic curve diagram showing the relationship between the spin-off test period and the change in the lubricant layer thickness when The characteristic curve diagram shown in FIG. 12 is a characteristic curve diagram showing the relationship between the number of tests and the change in the friction coefficient of the magnetic disk according to an embodiment of the present invention.

In these drawings, al) is a vacuum chamber, 02) is a high-frequency power supply, ■ is a high-frequency electrode, circle is a ground electrode, old is a vacuum pump, (g) is a gas inlet, ribs are oxygen gas, and (g) is a sample. , (211 is a sample stage, is an ultraviolet light source, (31) is an ozone generator, (32) is a container, (41) is an ion gun,
(42) is nitrogen gas, (43) is bias power supply, (51
) is a changeover switch, (52) is electrode A, (53)
Electrode B1 (54) is a carbon target, (55) is argon gas, (61) is methane gas, and (82) is hydrogen gas.

In addition, curves (a), (mountain), (e), (small) and (e) in FIG. 8 indicate those according to Example 1, Example 2, Example 3, Example 4, and Example 5, respectively. , (note that the curve (
a also indicates Example 6), curve +f+ in FIG. 9, (9
), song and +i+ indicate those according to Example 7, Example 9, Comparative Example 1 and Comparative Example 2, respectively (curve (f
) also indicates Examples 1O111, 12 and 13).

In addition, curves (j), (i, (1) and (
ml is from Example 14, Example 15, Comparative Example 3, and Comparative Example 4, respectively, and lines (n) and (0) in FIG.
and (p) indicate those according to Example 7, Example 9, and Comparative Example 1, respectively (line in+ also indicates Example 14, and line (p) also indicates Comparative Example 3). Furthermore, the curves +q>, Q), (S) and (1) in FIG. 12 are respectively for Comparative Example 1.
, Comparative Example 2, Example 7 and Example 9 are shown (curve (S) is Example 10111.12 and 13).
(also shown).

In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Embodiment 1 FIG. 2 is a schematic diagram of a high frequency plasma CVD apparatus for manufacturing the disk.

N1-P is placed on the aluminum alloy substrate (1) in advance.
Prepare a disk substrate (4) coated with a plating film (2) and on which a Co-Ni-Cr alloy is sputtered to a thickness of 500 mm as a magnetic tank (3) for a magnetic recording/reproducing medium. On top of that, carbon was sputtered to a thickness of 500 mm as a protective film (5).This was connected to a high-frequency electrode connected to a high-frequency power source 02) in a vacuum chamber (mouth) constituting a high-frequency plasma CVD processing chamber as shown in Figure 2. It was placed on 0.

Then, a ground electrode (14) was installed in parallel with the high frequency electrode (2). Next, the old vacuum pump was operated to once draw the inside of the vacuum chamber to a high vacuum, and then 02 gas flow was introduced into the vacuum chamber 01) from the gas inlet (g). Next, a high frequency voltage of 13.56 MHz was applied between the high frequency electrode 0 and the earth electrode to generate plasma between the electrodes.

Then, the carbon protective film (5) surface was plasma-treated under appropriate conditions with a gas pressure of 1 to 1000 III TOrr and a discharge power of 2 to 200 W.

The curve in Figure 8 shows the results of evaluating the hydrophilicity of the surface of the carbon protective film (5) using the contact angle of pure water. , the pressure was 300 mTorrs, and the discharge power was 25 W.When no plasma treatment was performed, the contact angle was large and the hydrophilicity was not very good, but with the plasma treatment, the contact angle became smaller, indicating that the hydrophilicity was improved. In addition, spectrum analysis of the surface of the carbon protective film using xPS revealed that plasma treatment increases the amount of oxygen present on the surface, resulting in the formation of functional groups such as -OH groups on the surface of the carbon protective film. Understood.

Embodiment 2 FIG. 3 is a schematic diagram of an ultraviolet irradiation device for manufacturing the disk.

The magnetic disk substrate (4) was prepared, and a carbon protective film (5) was formed thereon to a thickness of 50 OA by sputtering. This was placed on the sample stand (211) in the vacuum chamber 011 that constitutes the ultraviolet irradiation device shown in FIG. was operated to once draw a vacuum inside the vacuum chamber 01), and then 02 gas 07 was introduced into the vacuum chamber 01) from the gas introduction Hita. Gas pressure 1-500To
Set appropriate conditions within the range of rr, turn on the ultraviolet light source [Co., Ltd.] and irradiate ultraviolet light to remove the carbon protective film (5).
The surface was treated with ultraviolet irradiation.

Curve (b) in FIG. 8 shows the results of evaluating the hydrophilicity of the surface of the carbon protective film (5) using the contact angle of pure water.

The conditions for the ultraviolet irradiation treatment are 02 gas and a pressure of 100
A Torr, 500W low pressure mercury lamp was used as the ultraviolet light source. As in Example 1, the hydrophilicity of the surface of the carbon protective film was improved by UV irradiation.

Embodiment 3 FIG. 4 is a schematic diagram of an ozone treatment apparatus having an ozone generator for manufacturing the disk.

The magnetic disk substrate (4) was prepared, and a carbon protective film (5) was formed thereon to a thickness of 500 mm by sputtering. This was placed on the sample stand (3) in a container (32) having an ozone generator (31) as shown in FIG. Container (32)
An oxygen gas tube was introduced into the chamber to generate ozone, and the surface of the carbon protective film (5) was treated with ozone.

Curve (C) in FIG. 8 shows the results of evaluating the hydrophilicity of the surface of the carbon protective film (5) using the contact angle of pure water.

As in Example 1, the ozone treatment improved the hydrophilicity of the surface of the carbon protective film.

Example 4 FIG. 5 is a schematic diagram of an ion bombardment apparatus for manufacturing the disk.

The magnetic disk substrate (4) was prepared, and a carbon protective film (5) was formed thereon to a thickness of 500 mm by sputtering. This was placed on the sample stage in the vacuum chamber 01) constituting the ion bombardment device shown in Fig. 5, and the ion gun (41
) was installed on the sample stage (2V).Next, vacuum pump b was operated to once draw the inside of vacuum chamber 01 to a high vacuum,
Pressure 0. Nitrogen gas (42) under O1~100sTorr
was ionized by an ion gun (41) and irradiated onto the sample aa, and the surface of the carbon protective film (5) was subjected to ion bombardment treatment.

The curve in FIG. 8 (small) shows the results of hydrophilicity evaluation of the surface of the carbon protective film (5) using the contact angle of pure water.

In the ion bombardment process, nitrogen gas was ionized using an ion gun, and the surface of the carbon protective film was irradiated with nitrogen ions under a pressure of 1 mTorr. As in Example 1, the hydrophilicity of the surface of the carbon protective film was improved by the ion bombardment treatment.

Example 5 FIG. 6 is a schematic diagram of a sputtering apparatus for manufacturing the disk.

The magnetic disk substrate (4) is prepared and placed on the electrode A (52) connected to the high frequency power source 0 through the polarity changeover switch (51) in the vacuum chamber (former) that constitutes the sputtering apparatus shown in FIG. I placed it. Then, electrode B (51) connected to the polarity changeover switch (51) is connected to electrode A (
52) installed on top. A carbon target (54) was placed on the electrode B (53). Next, operate the old vacuum pump to evacuate the inside of vacuum chamber 01), and then
R gas (55) was introduced into the vacuum chamber (old) from the gas inlet (c). Subsequently, the polarity changeover switch (51) was switched to apply a high frequency voltage to the electrode B (53), and a carbon protective film (5) was sputtered to a thickness of 500 mm on the magnetic disk substrate (4). Thereafter, the selector switch (51) was switched to apply a high frequency voltage to the electrode A (51) to reverse sputter the surface of the protective film (5).

Curve (e) in FIG. 8 shows the results of evaluating the hydrophilicity of the surface of the carbon protective film (5) using the contact angle of pure water.

The conditions for forming the carbon protective film at this time were a pressure of 5 mTo.
The high frequency power was 500W. The reverse sputtering conditions were a pressure of 80 mTorr and a high frequency power of 10 mTorr.
It was 0w. When the reverse sputtering treatment is not performed, the contact angle is large and the hydrophilicity is not very good, but by performing the reverse sputtering treatment, the contact angle becomes smaller, indicating that the hydrophilicity is improved.

Embodiment 6 FIG. 7 is a schematic diagram of a high frequency plasma CVD apparatus for manufacturing the disk.

N1-P is placed on the aluminum alloy substrate (1) in advance.
A plating film ('2J) is coated, and 50% of Go-Nl-Cr alloy is coated on top of it as the magnetic layer (3) of the magnetic recording and reproducing medium.
Disk substrate (4) formed by sputtering to a thickness of 0.
was prepared and placed on the high frequency electrode connected to the high frequency power supply (+21) in the vacuum chamber 01) constituting the high frequency plasma CVD processing chamber shown in Fig. 7.Then, the ground electrode 04) was placed on the high frequency electrode connected to the The electrodes were placed parallel to each other. Next, the vacuum pump 4 was operated to once draw the inside of the vacuum chamber to a high vacuum, and then a mixed gas of methane gas (61) and hydrogen gas (62) was introduced into the vacuum chamber from the gas inlet □□□. Next, between the high frequency electrode 0a and the earth electrode 041, 13
．． A high frequency voltage of 58 MHz was applied to generate plasma between the electrodes. And gas pressure 1~1000a+Tor
r.

The carbon protective film (5) is placed on the magnetic disk substrate (4) under appropriate conditions with a discharge power of 2 to 200 W.
It was formed to a thickness of 0. Next, the gas was switched to the oxygen gas side and introduced into the vacuum chamber from the gas inlet 0■.

Next, a high frequency voltage was applied between the high frequency electrode U and the earth electrode 04) to generate plasma between the electrodes. Gas pressure 1~
The surface of the carbon protective film (5) can be continuously treated by installing under appropriate conditions such as 1000 iTorr and discharge power in the range of 2 to 200 W.

The curve (ω in Figure 8) shows the results of evaluating the hydrophilicity of the surface of the carbon protective film (5) using the contact angle of pure water.The conditions for forming the carbon protective film at this time are pressure, 30
The temperature was 0 mTorr and the high frequency power was 60 V.

In addition, the conditions for the plasma treatment were a pressure of 300 iTorr,
The high frequency power was 25W. When plasma treatment is not performed, the contact angle is large and hydrophilicity is not very good, but by plasma treatment, the contact angle becomes smaller, indicating that hydrophilicity is improved.

Fluorine-based polar lubricant used The fluorine-based polar lubricant having a hydrophilic functional group in the molecule used in the present invention is a fluorine-based polar lubricant having at least one carboxyl group, preferably 1 to 20 carboxyl groups in the molecule. You can use any one you have. Specific examples thereof include, for example, general formula (I): and general formula (■): HOOC-CF20- (C2Fa O) -(CF
20), -CF2-COOH■ (in the formula, ■ represents a natural number from 1 to 50, and 1 represents a natural number from 1 to 50), general formula ID:P-(CF2)
Examples include those represented by -COOHQ[) (in the formula, g represents a natural number from 1 to 20).

As a specific example of the general formula (Il), for example, KRYTOX 157FS (Ll, K
RYTOX157FSM, KRYTOX 157FS
Examples include H (each is a trade name, the subscripts (Ll, (Corporate), and ■ are each divided by average molecular weight, and n in the molecular formula is different).

A specific example of the compound represented by the general formula (Ml) is Z-DIAC (trade name) manufactured by Monteflores.

As a specific example of the compound represented by the general formula (3), for example, Megafac P-120 manufactured by Dainippon Ink and Chemicals
(trade name, formula: P (CF2)8-COOH).

Other fluorine-based polar lubricants may be used as long as they have at least one hydrophilic group such as an amino group, hydroxyl group, silanol group, sulfonic acid group, or phosphoric acid group in the molecule. As a specific example, the general formula (■, ■): Co Fly -NH2 (to) C8F+7- NHC284N1 (z
[V) Manufactured by Monteflores, Z-DOL (product name)
, general formula (vIl.

■ (In the formula, nSm is a natural number from 1 to 20) General formula ■ ~ (XI
): Cal F17-0(OH)2 C6F+7-8038 Cs Fy -081(0083) 3C6Fly -
Examples include those represented by 031(OC2N5)2C)Is. The above compound is described in the Proceedings of the Autumn National Conference of the Institute of Electronics, Information and Communication Engineers, 1988 C-8.

Example 7 A fluorine-based polar lubricant KRYTOX 1 was applied onto a magnetic disk substrate on which a protective film mainly made of carbon whose surface was modified to be hydrophilic was formed by the plasma treatment method of Example 1.
A magnetic disk was manufactured by applying 57FsM using a dip coating method. In addition, as conditions for coating, KRY
TOX 157PsM was diluted in a fluorine solvent (trifluorotrichloroethane) at a concentration of 3 g/l, and the substrate was immersed therein at a substrate pulling rate of 0.1 m/sin. The thickness of the lubricant layer at this time was about 34 layers.

A detailed explanation of the dip coat method can be found in the proceedings of the 32nd National Conference of the Japanese Society of Lubrication (Osaka), pages 485-488 (
1987).

Example 8 Instead of plasma using 02 gas used in Example 7,
N2, NH3, N20, Co, CO2, atmosphere (02
2N2-1:4) or other gas plasma,
A magnetic disk of Example 8 was produced in exactly the same manner as Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed. The thickness of the lubricant layer at this time was about 34 layers.

Example 9 The magnetic disk of Example 9 was produced in exactly the same manner as in Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface was modified to be hydrophilic was formed by the ultraviolet irradiation method of Example 2. was created. The thickness of the lubricant layer at this time was about 28 layers.

Example 1O The magnetic disk of Example 10 was prepared in exactly the same manner as in Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed by the ozone treatment method of Example 3. Created. The thickness of the lubricant layer at this time is approximately 33 mm.
It was a person.

Example ti The magnetic disk of Example 11 was produced in exactly the same manner as in Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed by the ion bombardment method of Example 4. Created. The thickness of the lubricant layer at this time was approximately 33 layers.

Example 12 The magnetic disk of Example 12 was prepared in exactly the same manner as in Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed by the reverse sputtering method of Example 5. Created. The thickness of the lubricant layer at this time is approximately 34 mm.
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Example 13 The magnetic disk of Example 13 was prepared in exactly the same manner as in Example 7 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed by the plasma CVD method of Example 6. Created. The thickness of the lubricant layer at this time was about 34 layers.

Example 14 Fluorine-based polar lubricant KRYTOX 1 was applied on the magnetic disk substrate used in Example 7, on which a protective film mainly made of carbon whose surface was modified to be hydrophilic by a plasma method was formed.
A magnetic disk was manufactured by applying 57PSM using a dip coating method. In addition, the conditions at the time of application, KRY
TOX 157PSM was diluted in a fluorine solvent (trifluorotrichloroethane) at a concentration of 7 g/l, and the substrate was immersed therein at a substrate pulling rate of 0.1 m/sin. The thickness of the lubricant layer at this time was about 57 people.

Example 15 The magnetic disk of Example 15 was produced in exactly the same manner as in Example 14 on a magnetic disk on which a protective film mainly made of carbon whose surface had been modified to be hydrophilic was formed by the ultraviolet irradiation method of Example 2. Created. The thickness of the lubricant layer at this time is approximately 5
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Comparative Example 1 Instead of the magnetic disk substrate used in Example 7, whose surface was modified to be hydrophilic by a plasma treatment method and a protective film mainly composed of carbon was formed, a conventional film formed by a sputtering method was used. A magnetic disk of Comparative Example 1 was produced in exactly the same manner as in Example 7 except that a substrate having a protective film mainly composed of carbon was used. The thickness of the lubricant layer at this time is approximately 19
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Comparative Example 2 In place of the fluorine-based polar lubricant used in Example 7, KRY manufactured by DuPont, which is an isomorphic lubricant having no polar group, was used.
TOX 143^D (product name), general formula (xn): P-
(CP-CF20) -CFs (X
II) A magnetic disk of Comparative Example 2 was produced in exactly the same manner as in Example 7 except that CP3 (in the formula, n is a natural number from 1 to 50) was used. The thickness of the lubricant layer at this time was about 20 layers.

Comparative Example 3 Instead of the magnetic disk substrate used in Example 14, on which a protective film mainly made of carbon whose surface was modified to be hydrophilic by plasma treatment was formed, a conventional carbon film formed by sputtering was used. A magnetic disk of Comparative Example 3 was produced in exactly the same manner as in Example 14, except that a substrate having a main protective film was used. The thickness of the lubricant layer at this time is approximately 4
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Comparative Example 4 Example 14 except that in place of the fluorine-based polar lubricant used in Example 14, KRYTOX 141AD manufactured by DuPont, a lubricant of the same series without polar groups, used in Comparative Example 2 was used. A magnetic disk of Comparative Example 4 was produced in exactly the same manner as above. The thickness of the lubricant layer at this time was about 40.

Spin-off Test A spin-off test was conducted for Examples 7.9, 10111.12, and 13 and Comparative Examples 1 and 2 to determine the reliability of the lubricant layer of the magnetic recording medium. FIG. 9 shows the change in lubricant layer thickness over the test period. Further, the results of the spin-off test for Examples 14 and 15 and Comparative Examples 3 and 4 are shown in FIG. 1O. However, the spin-off test referred to here means that the magnetic disk to be sampled is mounted on a spindle motor, and the test is carried out at a temperature of 65°C.
After installing it in a constant temperature and humidity chamber at ℃ and 20% humidity, rotate the spindle motor at 8BOOrp II (the magnetic disk also rotates at 3600 "p■"), and the film thickness of the lubricant tank on the magnetic disk surface due to this rotation. This is a test to evaluate changes.In other words, if the thickness of the lubricant layer decreases significantly as the magnetic disk rotates, this indicates that a spin-off phenomenon has occurred, resulting in a deterioration of the lubricating effect.Especially in C8S.
In operation tests, when the lubricant layer becomes thinner than a certain thickness, an increase in frictional force due to C8S becomes a problem, and if the lubricant layer is applied too thick, adsorption phenomenon between the head and the disk occurs, so the thickness of the lubricant layer is It is known that there is a certain appropriate thickness range for
987)).

In this evaluation of the lubricant layer thickness, a film thickness measurement method using FT-IR (Fourier transform infrared absorption spectroscopy) was used. The method includes:
It is calculated from the infrared absorption intensity shown by the lubricating layer.

For details, please refer to the above-mentioned references, the proceedings of the 32nd National Conference of the Japanese Society of Lubrication (Osaka), pages 485-48g (
19g? ) is explained in

From FIG. 9, it can be seen that in the magnetic disks of Examples 7.9.1O5ILl2 and 18 of the present invention, there was little change in the lubricant layer thickness due to spin-off, and even after the test, the lubricant layer remained approximately 30 mm thick. On the other hand, in the magnetic disks of Comparative Example 1 of the conventional type and Comparative Example 2 of the type using a lubricant without polar groups, the thickness of the lubricant layer decreased significantly, and spin-off clearly occurred. The remaining lubricant is thinner and the coefficient of friction increases due to C8S.

Moreover, FIG. 1O shows the results of a spin-off test in which the lubricant concentration at the time of lubricant application was increased to 7 g/l to increase the coating film thickness. The final film thickness is the same as with a lubricant concentration of 3 g/l, with Examples 14 and 15 having approximately 30 g/l of lubricant remaining, whereas Comparative Examples 3 and 4 after the spin-off test. The film thickness is thin and the coefficient of friction increases. Furthermore, since the initial film thickness is large at this concentration, there is also concern about the possibility of adsorption.

Here, we investigated the reason why the magnetic disk of the present invention is better against spin-off compared to conventional magnetic disks, and found that Examples 7.9.10.11゜12 and 13
The thickness of the lubricant layer coated on the disks of Comparative Examples 1 and 2 was thicker than that of the disks of Comparative Examples 1 and 2, even though they were coated under the same conditions. KRYTOX, a protective film mainly made of carbon whose surface has been modified to be hydrophilic, and a fluorine-based polar lubricant
It was found that there was an interaction with the carboxyl group in the 157PSM molecule. From this, it is considered that the lubricating layer, which is a component of the magnetic disk of the present invention, is firmly fixed on the carbon film through interaction, resulting in the formation of a lubricating layer that is difficult to spin off. Note that FIG. 11 shows the relationship between the lubricant application conditions and the lubricant layer thickness.

C8S test Next, after performing the spin-off test, a C8S operation test, which indicates the reliability of the magnetic recording medium, was performed on the above embodiment and comparative example. The relationship between the number of C8S operation tests and the coefficient of friction generated between the head and the disk was determined in the 12th test.
As shown in the figure.

From FIG. 12, it can be seen that the increase in the friction coefficient due to the C8S operation test for the magnetic disks of Examples 7.9.11.12 and 13 was not significantly small, whereas it was significantly large for the magnetic disks of Comparative Examples 1 and 2. I understand that. From this, it can be seen that the magnetic disk of the present invention suffers little mechanical deterioration due to sliding contact with the magnetic head, and it can be seen that the effect of the lubricating layer is remarkable. Regarding the C8S operation test method, see Journal of Precision Mechanical Engineering, 54.5, pys~
It is introduced in detail in 79 (198g) etc.

In the above embodiments, a parallel plate type high frequency plasma CVD device or sputtering device was used as the manufacturing device.
It goes without saying that in the present invention, other well-known microwave ion sources, plasma CVD apparatuses using direct current, and sputtering apparatuses can also be used as plasma generating means.

Furthermore, although the embodiments of the present invention have been described with respect to magnetic disks, it is clear that the present invention is also effective for floppy disks, magnetic tapes, and magnetic cards.

[Effects of the Invention] As described above, in the magnetic disk according to the present invention, a magnetic layer is formed on a substrate, and a protective film mainly composed of carbon whose surface has been modified to be hydrophilic is formed on the magnetic layer. Due to the interaction with the fluorine-based polar lubricant molecules that have functional groups, the lubricant layer that is formed as a result is strongly retained on the carbon protective film, and the spin-off phenomenon, or scattering, of the lubricant layer as the disk rotates. It has sufficient mechanical durability with almost no evaporation. Furthermore, since the total thickness of the layers formed on the magnetic layer can be reduced, spacing loss between the magnetic layer and the magnetic head is reduced, and the reproduction characteristics of the magnetic recording medium can be maintained favorably. Therefore, it is possible to replace a magnetic disk that has excellent durability and does not reduce playback output.

Furthermore, as a method and apparatus for modifying the surface of a carbon protective film to make it hydrophilic, a protective film made of carbon can be created in a vacuum, and then hydrophilic modification can be performed without breaking the vacuum, making it a throughput for mass production. It also has the effect of making you feel better.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a magnetic disk showing one embodiment of the present invention, and FIG. 2 is a plasma CVD system for implementing the present invention.
A schematic explanatory diagram showing an example of an apparatus, FIG. 3 is a schematic explanatory diagram showing an example of an ultraviolet irradiation apparatus for carrying out the present invention,
FIG. 4 is a schematic explanatory diagram showing an example of an ozone treatment apparatus for implementing the present invention, FIG. 5 is a schematic explanatory diagram showing an example of an ion bombardment apparatus for implementing the present invention, and FIG.
FIG. 7 is a schematic explanatory diagram showing an example of a sputtering apparatus capable of continuous processing for implementing the present invention, FIG. 7 is a schematic explanatory diagram showing an example of a plasma CVD apparatus capable of continuous processing for implementing the present invention, FIG. 8 is a characteristic curve diagram showing the relationship between various modification treatment times and changes in the contact angle on the surface of the carbon protective film, showing an example of the present invention, and FIG. A characteristic curve diagram showing the relationship between the spin-off test period and the change in lubricant layer thickness when the coating concentration is 3 g/l, and FIG. 10 shows an example of the present invention when the coating concentration of the lubricant is 7 g/l.
Figure 11 is a characteristic curve diagram showing the relationship between the spin-off test period and the change in lubricant layer thickness when I.
A characteristic curve diagram showing the relationship between the concentration of RYTOX 157PSMl and a change in coating film thickness, and FIG. 12 is a characteristic curve diagram showing the relationship between the number of C8S tests and a change in the coefficient of friction of a magnetic disk, showing an example of the present invention. It is. (Main symbols in the drawings) (1): Non-magnetic substrate (3) Two-alloy magnetic layer (5): Carbon protective film (6): Lubricant layer agent Masuo Hitoiwa 1st Fang 2 Diagram: Non-magnetic substrate: Alloy magnetic layer: Carbon protective film, lubricant layer material Figure 3 Figure 4 Figure 6 (Spontaneous) 1. Case display holder-2-140814 No. 3, person making the amendment (contact number 03 (32+3) 34?I4.'r'yr department)
to correct. 5. Subject of amendment (1) Column 6 of “Detailed Description of the Invention” of the specification, Contents of amendment (1) Change “toto wa” from “toto wa” in line 1 on page 5 of the specification
and correct it. (2) Correct r ARJ in line 4 of page 13 to r ArJ. (3) Correct “sample box” in line 16 of page 1B to “sample stand.” (4) Correct r(V)J on page 21, line 15 to r(r)J. (5) On page 22, lines 5-6, “The plating film (2) is coated,
On top of that, the magnetic tank of the porcelain recording and reproducing medium is covered with a plating film (
2) is coated with a magnetic layer of a magnetic recording/reproducing medium on top of the magnetic layer. (6) On page 33, line 10, ``noyoto'' is corrected to ``by''.

Claims (3)

[Claims] (1) A magnetic disk comprising a substrate having a non-magnetic base and a magnetic layer, a protective film mainly made of carbon formed on the magnetic layer, and a fluorine-based polar lubricant layer, the fluorine-based polar lubricant being A magnetic disk in which the lubricant layer has a hydrophilic functional group in its constituent molecules, and the fluorine-based polar lubricant layer is formed by coating on the surface of the protective film layer which has been improved in hydrophilicity. (2) A substrate having a magnetic layer on a non-magnetic substrate is prepared, a protective film mainly composed of carbon is formed on the magnetic layer, the surface of the protective film is modified to be hydrophilic, and then a hydrophilic functional group is added to the surface of the protective film. 1. A method for manufacturing a magnetic disk, comprising coating and forming a fluorine-based polar lubricant contained in constituent molecules. (3) A sample consisting of an airtight container, a negative pressure generator that can make the container negative pressure, and a substrate on which a nonmagnetic substrate and a magnetic layer are formed, and a protective film mainly made of carbon is formed. 1. An apparatus for manufacturing a magnetic disk, comprising a stand, a reactive gas supply device, and a reactive gas excitation device, and is configured to be able to modify the surface of the protective film to be hydrophilic.