JPH0423219A - Magnetic disk and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic disk, and more particularly to a magnetic recording medium on which a crack protection film and a lubricant layer are formed to improve durability, and a method for manufacturing the same. It is something.

(Prior Art) In recent years, the importance of external storage devices such as magnetic disks in computer systems has increased, and with this, there has been an increasing demand for higher recording densities in magnetic storage devices using magnetic disks. It's increasing. 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, and 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 was reduced, and a contact start/stop (CSS) type head floating system was adopted. There is. In order to increase the recording density and performance of magnetic disks, it is necessary to make the magnetic recording medium thinner, more uniform, improve magnetic properties, and ensure a stable head flying state at a low flying height. It is necessary to improve the precision of the surface roughness of the disk, which should prevent collisions between the head and the disk (head crash), and to improve the head crash resistance. However, as the accuracy of the roughness of the disk surface improves, the coefficient of dynamic friction when the magnetic disk and the magnetic head come into contact with each other increases significantly, resulting in a disadvantage that the sliding characteristics of the head flying are poor.

Conventional magnetic disks include Fe on resin film substrates, aluminum alloy substrates, or N1-Cu-P alloy substrates.
A layer made of Fe oxide was formed by reactive sputtering using carbon dioxide and oxygen, and then oxidized in the air to form a magnetic layer made of γ-Fe2O3, as well as Nj- It is known that an underlayer of P alloy is formed by a plating method, and a magnetic layer of N1-Go-P alloy is further formed thereon by a plating method.

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

In order to eliminate these drawbacks and protect the underlayer and magnetic layer of the magnetic disk, a protective film made of carbon has been conventionally formed on the magnetic layer by sputtering, electron beam evaporation, or CVD. Furthermore, a protective film is formed by applying a fluorine-based lubricant thereon by a spin coating method or a dip coating method. Furthermore, such conventional technology is described in the Journal of the Japanese Society of Applied Magnetics, vol.
, No.], p, 6 (+988), etc.

[Problem to be solved by the invention]

Are conventional magnetic disks configured as described above?
For magnetic disks with a protective film made of carbon as described above, it is difficult to retain the fluorine-based lubricant applied on the carbon protective film, and the fluorine-based lubricant may scatter as the magnetic disk rotates, or the fluorine-based lubricant may scatter over time and Depending on the temperature at which the fluorine-based lubricant is left, it may evaporate and the lubricating effect of the protective layer on the magnetic head may deteriorate, making the magnetic disk or magnetic head more susceptible to damage or causing insufficient durability and reliability. There was a problem that it was not possible to obtain the required amount. Regarding the above phenomenon, please refer to the magazine (E, E, Klans and B
, Bushhan; ASLE 5P-20 (1985
) etc.

The present invention has been made to solve such conventional problems, and replaces the carbon protective film with a protective film made of a carbon film containing at least one metal element selected from the metal group consisting of Si, GeSn, and PB. In addition, by applying a fluorine-based lubricant that has a hydrophilic functional group in its molecule, there is almost no scattering or evaporation of the lubricant after the lubricant has been applied, and as a result, the reproduction output does not decrease. Furthermore, the first object is to provide a magnetic disk having practically sufficient fire resistance and corrosion resistance, and the second object is to provide an improved method for manufacturing the magnetic disk.

[Means to solve the problem]

The magnetic disk according to the present invention has a thin magnetic layer on a non-magnetic substrate, and has Si on the magnetic layer.

A protective film made of a carbon film containing at least one metal element selected from the metal group consisting of Ge, Sn, and Pb is formed, and furthermore, a carboxyl group, an amino group, a hydroxyl group, a silanol group, a sulfonic acid group, phosphate group,
A fluorine-based polar lubricant layer having a hydrophilic functional group such as in its constituent molecules is formed by coating.

In addition, in such a magnetic disk, a substrate in which a metal magnetic layer is formed on a non-magnetic substrate is placed on a sample stage installed in a sputter deposition chamber using carbon as a target, and the chamber is placed in a high vacuum. After evacuation, argon (Ar) and hydrides of the above metals (SiH4, GeH4, SnH4, PbH
4, etc.), alkyl compounds (-formula: S i R4, G
eR4, 5nR4, PbR4, etc.), alkoxy compounds (
-Formula: S i (OR)4, Ge (OR)4.
5n (OR), Pb (OR) 4, etc.), (in any of the formulas, R is, for example, a methyl group CH3
, ethyl group C2H5, propyl group C3H7, butyl group C
A carbon protective film containing the above-mentioned metal is formed by supplying a mixed gas containing at least one type of alkyl group represented by 4H9, etc., and performing sputtering at a gas pressure of 1 to 100 mTorr and a discharge power of 20 to 2000 W. It can be manufactured by coating a membrane with a fluorine-based polar lubricant having hydrophilic functional groups such as carboxyl groups, amino groups, hydroxyl groups, silanol groups, sulfonic acid groups, and phosphoric acid groups in its constituent molecules. I'll come.

[Effect]

In the present invention, the metal atoms in the protective film made of a carbon film containing at least one metal element selected from Si, Ge, Sn, and Pb are fluorine-based polar lubricants having more hydrophilic functional groups than carbon atoms. The interaction becomes stronger by forming salts with agent molecules or electrostatic bonds such as ionic bonds, and the fluorine-based polar lubricant is strongly retained on the carbon film, resulting in the lubricant molecules scattering. It is possible to obtain a magnetic disk with sufficient mechanical durability and sufficient water leakage properties even if the lubricant layer is thin, with almost no evaporation or evaporation occurring.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a sectional view showing a magnetic disk according to an embodiment of the present invention. In Figure 1, (1) is a non-magnetic substrate made of aluminum alloy with a thickness of about 1.9 mm, and (2) is a non-magnetic substrate made of an N1-P alloy formed on the substrate (1) with a thickness of about 10 μm. (3) is N1-C formed on the base layer (2).

The magnetic layer is made of a Cr alloy and has a thickness of about 500 mm (4
) is Sl formed on the magnetic layer (3).

The protective film layer has a thickness of approximately 300 mm and is made of a carbon film containing at least one metal element selected from the metal group of Ge, Sn, and Pb. Above all, (5) is a fluorine-based polar lubricant layer having a hydrophilic functional group in its constituent molecules, and is coated with KRYTOX 157FS (M) described later by a dip coating method. The thickness was approximately 39 people.

Next, an example of a method for forming a carbon protective film layer made of a carbon film containing at least one metal element selected from the metal group of Si, Ge, Sn, and Pb will be described.

FIG. 2 is a schematic diagram of a DC sputtering apparatus for manufacturing the above disk.

In advance, the substrate (20) on which the magnetic layer (3) in FIG. A carbon target (13) is placed on a target electrode (15) connected to a DC power source (14). Then, a ground electrode (12) and a target electrode (15) are installed in parallel. Next, the vacuum pump (16) is operated to once draw the inside of the vacuum chamber to a high vacuum, and then GeH, scum (17) and Ar are removed.
The waste (18) is introduced into the vacuum chamber through the gas inlet (19). Next, the ground electrode (12) and the target electrode (15)
) to generate plasma between the electrodes. And the mixed gas pressure is 1 to 100 mT.

rr and discharge power in the range of 20 to 2000 W, and a germanium-containing carbon protective film was sputtered to a thickness of about 300 mm on the magnetic layer (3).

GeH4 scum (17) and Ar from the gas inlet (19)
The composition ratio of germanium to carbon in the film was evaluated by changing the flow rate ratio of gas (18). Figure 5 shows an example 1
- Characteristic curve diagram. The sputtering conditions at this time were a mixed gas pressure of 10 mTorr and a discharge power of 500 W.

FIG. 3 is a schematic diagram of another DC sputtering apparatus for manufacturing the above disk.

In advance, the substrate (20) on which the magnetic layer (3) has been formed in FIG. , Ge-containing carbon tarwatt 21) with direct current #, (14
) is placed on the target electrode (15) connected to the target electrode (15).

And the ground electrode (12) and the target electrode 8i (+5)
are installed in parallel. Next, the vacuum pump (16) is operated to once draw the inside of the vacuum chamber to a high vacuum, and then Ar gas (18) is introduced into the vacuum chamber from the gas inlet (19). Next, a DC voltage is applied between the earth electrode (12) and the target electrode (15) to generate plasma between the electrodes.

At this time, an alloy target containing 0.01 to 10 atm % of germanium in carbon was used as the target (21). Then, the magnetic layer (3) is coated with a germanium-containing carbon protective film on the magnetic layer (3) under appropriate conditions such as a gas pressure of 1 to 100 mTorr and a discharge power of 20 to 2000 W.
A film was deposited by sputtering to a human thickness.

The composition ratio of germanium to carbon in the protective film was evaluated when the germanium content in the alloy target was changed. FIG. 6 is a characteristic curve diagram showing an example of this.

The sputtering conditions at this time were an Ar gas pressure of 5 mTorr and a discharge power of 500 W.

FIG. 4 is a schematic diagram of a high frequency plasma CVD apparatus for manufacturing the above disk.

To summarize, the substrate (20) on which the magnetic layer (3) in FIG. Place it on the high frequency electrode (23). Then, a ground electrode (12) is installed in parallel with the high frequency electrode (23). Next, operate the vacuum pump (16) to once draw the inside of the vacuum chamber to a high vacuum, then CH4 gas (24) and GeH4 gas (17
) is introduced into the vacuum chamber through the waste inlet (19). Next, between the earth electrode (12) and the high frequency electrode (23), 13
A high frequency voltage of 56 MHz is applied to generate plasma between the electrodes. And those mixed gas pressure 1 to 10
A carbon protective film containing germanium was formed on the magnetic layer (3) to a thickness of about 300 mm under appropriate conditions such as 00 m Torr and a discharge power of 2 to 200 W.

CH4 dregs (24) and GeH from the dregs inlet (19)
The composition ratio of germanium to carbon in the carbon protective film was evaluated by changing the flow rate ratio of 4 gases 17). FIG. 7 is a characteristic curve diagram showing an example of this.

The conditions for film formation by plasma CVD at this time were that the pressure of the mixed residue was 300 mTorr, and the discharge power was 60 W. After forming the protective film layer (4) on the substrate (20) in this manner, a lubricant layer (5) is formed on this protective film layer. The fluorine-based polar lubricant having a hydrophilic functional group in its molecule used in the present invention may be any fluorine-based lubricant having at least 1, preferably 1 to 20 carboxyl groups in its molecule. Even if there is, it can be used by an official. As a specific example, for example, - Formula (1): (where n is 1 to
(represents a natural number from 1 to 50), - represented by formula (II) (in the formula, m is a natural number from 1 to 50, and represents a natural number from 1 to 50), - formula (m) II F-(
CF2) g-cool-1(m) (where g is 1-2
Examples include those expressed as 0 (indicating a natural number).

Specific examples of those represented by general formula (I) include, for example, KRYTOX157FS(L), KRYTOX157FS(L), manufactured by DuPont.
TOX 157FS (M), KRYTOX 1
57 F S (H) (Character +7) (L), (M)
, (H) are divided by average molecular weight, and n in the molecular formula is different).

A specific example of the compound represented by the general formula (n) is Z-DI AC manufactured by Monteflores.

As a specific example of the compound represented by the general formula (I[l), for example, Mechafac F-
120 (2F-(CF2)8COOH).

Other fluorine-based polar lubricants may be those having 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, - formula (■, ■): Ca F
I7 NH2 (rv) C8F, 7-NHC2H4NH2 (V) Manufactured by Monteflores, Z-DOL, - Formula (Vl) HOCH2CF2
0 (C2F4 0).

-(CF20).

-CF2 CH20H (■) (where n and m represent natural numbers from 1 to 20, -numerical formula (■
~X[): F17-803 F, 7-03i (OCH3 (■) (IX) etc.).

The above-mentioned compound is described in "1986 Institute of Electronics, Information and Communication Engineers Autumn National Conference C-8".

Example 1 Germanium was prepared by the method shown in FIG.
A magnetic disk was manufactured by applying a fluorine-based polar lubricant KRYTOX157FS (M) by a dip coating method onto a substrate on which a carbon protective film containing atm% was formed. In addition, as conditions for coating, KRYTOX 157FS
(M) as a fluorine solvent (trifluorotrichloroethane)
The solution was diluted to 3 g/l, and the substrate was immersed in it at a substrate lifting speed of 0.1 m/min.

For a detailed explanation of the dip coat method, please refer to the Proceedings of the 32nd National Conference of the Japanese Society of Lubrication (Osaka) 2485-48B.
(1987) J et al.

Example 2 Instead of the carbon protective film containing 5 atm % germanium used in Example 1, 0.04, 0. 08
,0. 2, 0.6, 0. A magnetic disk of Example 2 was produced in exactly the same manner as Example 1 except that a substrate having a carbon protective film containing 9.8 atm % was used.

Example 3 Example 3 was carried out in exactly the same manner as in Example 1 except that a substrate having a carbon protective film containing 5 atm% of silicon was used instead of the carbon protective film containing 5 atm% of germanium used in Example 1. A magnetic disk was fabricated.

Example 4 Example 4 was carried out in exactly the same manner as in Example 1 except that a substrate having a carbon protective film containing 5 atm% of tin was used instead of the carbon protective film containing 5 atm% of germanium used in Example 1. A magnetic disk was created.

Example 5 Example 5 was carried out in exactly the same manner as in Example 1 except that a substrate having a carbon protective film containing 5 atm% of lead was used instead of the carbon protective film containing 5 atm% of germanium used in Example 1. A magnetic disk was fabricated.

Example 6 ′i! A magnetic disk of Example 6 was manufactured in exactly the same manner as Example 1, except that a substrate having a carbon protective film containing 5 atm % germanium, which was manufactured by the method shown in FIG. 2, was used.

Example 7 Germanium was prepared by the method shown in FIG.
Except for using a substrate with a carbon protective film containing stm%.
A magnetic disk of Example 7 was produced in exactly the same manner as Example 1.

Comparative Example 1 Completely the same as Example 1, except that instead of the substrate with the germanium-containing carbon protective film used in Example 1, a substrate with a conventional carbon protective film formed by sputtering was used. A magnetic disk of Comparative Example 1 was produced in the same manner.

Comparative Example 2 Instead of the fluorine-based polar C lubricant used in Example 1, KRY manufactured by Duhon Co., Ltd., a lubricant of the same series without polar groups, was used.
TOX 143AD, - Formula % Formula %): ([) (In the formula, n represents a natural number from 1 to 50) A magnetic disk of Comparative Example 2 was produced in exactly the same manner as in Example 1 except that n was used.

A spin-off test was conducted on Example 1 and Comparative Examples 1.2 to show the reliability of the magnetic recording media. FIG. 8 shows the change in the lubricant layer H over the test period. However, the spin-off test referred to here means that the magnetic disk to be sampled is mounted on a spindle motor, and the magnetic disk is heated to 65°C.
℃ and 20% humidity, the spindle motor was rotated at 3600 rpm (the magnetic disk also rotated at 3600 rpm), and changes in the film thickness of the lubricant layer on the magnetic disk surface due to this rotation were observed. Refers to the test to be evaluated. That is, if the thickness of the lubricating layer decreases rapidly as the magnetic disk rotates, this indicates that a spin-off phenomenon has occurred, indicating that the lubricating effect has deteriorated. Particularly in C5S operation tests, if the lubricant layer becomes thinner than a certain thickness, the increase in frictional force associated with C8S becomes a problem, and if the lubricant layer is applied too thick, an adhesion phenomenon between the head and the disk occurs, so the lubricant layer It is known that there is an appropriate range of thickness within the range of
8 (1987)).

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

For details, please refer to the above-mentioned reference, "Proceedings of the 32nd National Meeting of the Japanese Society of Lubrication (Osaka)," pages 485-488.
(1987).

From FIG. 8, it can be seen that in the magnetic disk of Example 1 of the present invention, the change in the lubricant layer thickness due to spin-off is small, and a lubricant layer approximately 30 mm thick remains after the test, whereas in the case of the conventional magnetic disk. In the magnetic disks of type Comparative Example 1 and type Comparative Example 2 using a lubricant without polar groups, the thickness of the lubricant layer was significantly reduced, and spin-off clearly occurred, and the remaining lubricant layer thickness also increased. An increase in the coefficient of friction occurs when thin < CSS.

Here, we investigated the reason why the magnetic disk of the present invention is better against spin-off compared to the conventional magnetic disk, and found that the thickness of the lubricant layer coated on the disk of Example 1 was the same as that of Comparative Example 1. Even when applied under the same conditions, the lubricant layer was coated thicker than the lubricant layer coated on the disk of No. 2, so it was found that the carbon film containing germanium and the fluorine-based polar lubricant of the present invention were used. KRYTOX157FS (
M) It was found that there was an interaction with the carboxyl group in the molecule. This is because the metal atoms such as germanium in the carbon film and the hydrophilic functional groups in the lubricant molecules form salts or form electrostatic bonds such as ionic bonds, which form a larger bond than with carbon atoms. It is thought that this is because it has energy. From this, it is thought that the lubricant 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 lubricant layer that is difficult to peel off. . Furthermore, in Figure 9,
The relationship between lubricant application conditions and lubricant layer thickness is shown.

Further, Table 1 shows the results of a series of spin-off tests in Example 1.2 of the present invention. From Table 1, the thickness of the applied lubricating layer increases sequentially until the atm% amount of germanium in the carbon film becomes approximately 5%. This shows that as the amount of germanium in the film increases, the interaction with the lubricant layer becomes stronger.

It can also be seen that the film thickness of the lubricant layer after the 6-week spin-off test increases with the increase in germanium in the carbon film, confirming that the effect of preventing spin-off is large.

Next, after performing the spin-off test, a CSS operation test was performed on the above-mentioned Example and Comparative Example to show the reliability of the magnetic recording medium. The number of CSS operation tests at that time and the head at that time,
FIG. 10 shows the relationship between the friction coefficients generated between the disks.

From FIG. 10, it can be seen that in Example 1, the increase in the friction coefficient due to the CSS operation test of the magnetic disk was small, whereas in Comparative Example 1.
It can be seen that the size of the magnetic disk No. 2 is significantly larger. 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 C5S operation test method, please refer to "Journal of Precision Mechanical Engineering" 54゜5,
It is introduced in detail on pages 73-79 (1988).

Table 2 shows the results of the C3S operation test on the samples after the series of spin-off tests using Example 1.2 of the present invention. From Table 2, atm of germanium in carbon film
% or more, it can be seen that the effect of improving mechanical durability accompanying CSS operation is remarkable. Moreover, Table 3 shows the results of the CSS operation test using Examples 1.3 to 7 of the present invention and Comparative Example 1.2. From Table 3, Si, Ge, S
When a fluorine-based polar lubricant is coated on a carbon protective film containing 5% of either metal element among n and Pb, the friction coefficient does not exceed 0.5 even after 30,000 cycles of C3S. It can be seen that the effect of improving mechanical durability accompanying CSS operation is remarkable.

In the above, examples of the present invention have been shown in comparison with comparative examples, but the above-mentioned examples only use a small part of the carbon component raw material and the metal element component raw material. Similar effects can be obtained when other alkyl compounds and alkoxy compounds are used. When an alkyl compound or an alkoxy compound is used as the metal element component, a part of the carbon component can also be introduced simultaneously with the introduction of the metal element.

In addition, in the above embodiments, a DC sputtering device and a high frequency plasma CVD device were used as manufacturing equipment, but in the present invention, high frequency,
Needless to say, both DC and microwave ECR can be used.

Although the embodiments of the present invention have been described with respect to magnetic disks, the present invention is also effective for floppy disks, magnetic tapes, and magnetic cards.

〔Effect of the invention〕

As described above, the magnetic disk according to the present invention has a magnetic layer formed on a substrate, and silicon, germanium, etc.
After forming a protective film made of a carbon film containing at least one metal element selected from tin and lead, and further coating and forming a fluorine-based polar lubricant layer having a hydrophilic functional group on this protective film, Because the protective film interacts with lubricant molecules, the lubricant layer is strongly retained on the carbon protective film, and spin-off of the lubricant layer due to disk rotation, that is, almost no scattering or evaporation, occurs, and sufficient mechanical strength is maintained. It has a durable effect. Furthermore, since the total thickness of the layers formed on the magnetic layer can be reduced, the 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 obtain a magnetic tape which is excellent in durability and does not reduce the reproduction output.

In addition, such a magnetic disk is placed on a sample stage provided in a sputtering film forming chamber with 7 ib deposited on a non-magnetic substrate, and after the chamber is evacuated to a high vacuum, argon, silicon, germanium, Supplying a mixed gas containing at least one kind of hydride of at least one metal element selected from the metal group of tin and lead, an alkyl compound, and an alkoxy compound, a gas pressure of 1 to 200 mTorr,
A carbon protective film containing the metal element is formed by sputtering at a discharge power of 20 to 2000 W, and then a fluorine-based polar lubricant having a hydrophilic functional group in its constituent molecules is applied to the protective crotch. This can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a magnetic disk according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing an example of a DC sputtering apparatus for manufacturing a magnetic disk according to an embodiment of the present invention, and FIG. The figure is a schematic configuration diagram showing another example of a DC sputtering apparatus for producing a magnetic disk according to an embodiment of the present invention, and FIG. 4 is a high-frequency plasma CVD apparatus for producing a magnetic disk according to an embodiment of the present invention. A schematic configuration diagram showing an example, FIG. 5 is a characteristic curve diagram showing the relationship between the flow rate ratio of GeH4 gas used in the apparatus shown in FIG. 2 and the Ge content in the formed carbon protective film, and FIG. The figure is a characteristic curve diagram showing the relationship between the Ge content of the target used in the apparatus shown in Fig. 3 and the Ge content in the formed carbon protective film. FIG. 8 is a characteristic curve diagram showing the relationship between the flow rate ratio of the GeH4 gas used and the Ge content in the formed carbon protective film. FIG. 9 is a characteristic curve diagram showing the relationship between the concentration of KRYTOX 157FS (M) and the change in coating film thickness in the embodiment of the present invention and the conventional magnetic disk. 10 and 10 are characteristic curve diagrams showing the relationship between the number of C5S tests and the change in the friction coefficient of the magnetic disk in the embodiment of the present invention and the conventional magnetic disk. In the figure, (1) is a nonmagnetic substrate, (2) is an underlayer, (
3) is a magnetic layer, (4) is a protective film layer, (5) is a fluorine-based lubricant layer, (11 is a vacuum chamber, (13) is a carbon target, (17) is a Kerman gas, and (18) is an argon gas ,
(2o) is a substrate, and (21) is a Ge-containing carbon turf (24) is methane gas. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A protective film comprising a thin magnetic layer on a non-magnetic substrate, and a carbon film containing at least one metal element selected from the metal group of silicon, germanium, tin, and lead on the thin magnetic layer. is formed, and further on the above protective film,
A magnetic disk coated with a fluorine-based polar lubricant layer that has hydrophilic functional groups in its constituent molecules. (2) A substrate in which a thin magnetic layer is formed on a non-magnetic substrate is placed on a sample stage installed in a sputter film formation chamber with carbon as a target, and the chamber is evacuated to a high vacuum.
a hydride of argon and at least one metal element selected from the metal group of silicon, germanium, tin and lead;
A mixed gas containing at least one selected from an alkyl compound and an alkoxy compound is supplied, and the gas pressure is 1 to 10
A carbon protective film containing the above-mentioned metal element is formed by sputtering under the conditions of 0 mTorr and discharge power of 20 to 2000 W, and then a fluorine-based polar lubricant having a hydrophilic functional group in its constituent molecules is applied on the above-mentioned protective film. A method of manufacturing a magnetic disk by coating.