JP2001067644A - Coating lubricant for magnetic recording device and lubricating structure utilizing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lubricant for magnetic recording device capable of enduring a severe frictional condition for a long period by dispersing single or double layered hollow carbon nano-tubes having a hydrophobic group in a solvent. SOLUTION: When a magnetic disk 1 is in a standstill state, a head slider 2 stands still on a protective layer 3a via a hollow carbon nano-tube 6a. As the magnetic disk 1 begins to rotate from the state, the head slider 2 relatively moves while sliding on or floating just a little above the protective layer 3a. The hollow carbon nano-tube 6a is interposed therebetween and disturbs direct contact of the protective layers 3a and 3b with each other. The hollow carbon nano-tube 6a is not damaged buy sliding of the head slider 2 or impact at the time of contact because of its very light weight toughness, and elasticity and shows excellent lubricity. Therefore, the frictional coefficient when the head slider 2 slides on the protective layer 3 is drastically reduced. At the same time, the secular change of lubricity is also very little.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for, for example, a magnetic recording layer of a magnetic disk used in an information processing apparatus such as a computer or a work station, or a head slider disposed close to or in contact with the magnetic recording layer. The present invention relates to a lubricant for a magnetic recording device and a lubricating structure using the lubricant.

[0002]

2. Description of the Related Art In a recent magnetic recording apparatus, a magnetic head (200a) is mounted on a head slider (200) flying by air resistance (air lubrication) on a magnetic disk (100) rotating at a high speed. Recording / reproducing has been performed by writing data to the magnetic recording layer (400) in (200a) or reading data recorded in the magnetic recording layer (400). At present, as the magnetic recording density of the magnetic disk (100) increases dramatically, the distance (flying height) to the magnetic recording layer (400) of the magnetic head (200a) disposed along the magnetic recording layer (400) is increased. (H))
The bit interval (B) of the magnetic recording layer (400) has recently become 150 to 200 nm, and the flying height has been reduced to 40.
It is a number such as ~ 50 nm.

[0003] In the future, further improvement in magnetic density is expected, and as a matter of course, it is expected that the levitation height will be even smaller, or that it will rotate while contacting. (However, if the flying height is small, the control becomes extremely difficult, so the contact type is considered to be more effective.) In this case, the contact probability between the magnetic recording layer and the head slider (2) naturally increases dramatically. And wear of the contact surface becomes a major problem.

At present, a diamond-like carbon layer (300a) (300b) as a protective layer is formed on the contact surface between the magnetic recording layer (400) and the head slider (200), and a lubricating layer (300) is formed by applying a liquid lubricant. On the magnetic recording layer (400) side, a texture (700) (projections provided on the surface) having a height of 20 to 30 nm is formed. And at the time of operation (when the magnetic disk (100) is rotating),
Preferentially contact the head slider (200) that has abnormally approached or contacted the magnetic disk (100) with the texture (700);
The lubrication layer (600) minimizes the frictional resistance to minimize the wear of the protective layers (300a) (300b) and the magnetic recording layer (400), and minimizes the magnetic recording layer (40) from abrasion caused by contact.
0) is prevented from deteriorating or destroying.

[0005] The most important factor for the wear prevention is the lubricating layer (600). The most popular current lubrication layer (600) is a fluorocarbon film made of a lubrication layer (60
0) (JP-A-1-158622, JP-A-4-44636)
), Using a fluorinated graphite thin film having a graphite structure as a lubricating layer (600) (JP-A-56-156931, JP-A-56-156932, JP-A-64-156932), and a fluorine-based compound having a functional group. There is one using synthetic oil as the lubricating layer (600) (Japanese Patent Laid-Open No. 7-129949).

The lubricating layer (600) made of the above material has a limited number of times of contact of the head slider (200) with the magnetic recording layer under the current lubricating conditions, that is, in the case of a flying height of 40 to 50 nm. Although the above material is satisfactory, if the flying height is further reduced and the contact frequency is dramatically increased, or if the rotating is performed while maintaining the contact state, the material is extremely deteriorated and the lubricating performance is extremely short. Will not be maintained.

That is, a magnetic disk (10
When the head slider (200) comes into contact with (0), the contact position instantaneously becomes high in temperature, and if the lubricating layer (600) is made of only a chemical liquid lubricating material such as a fluorine-based synthetic oil,
It decomposes instantaneously, deteriorating the properties, and by repeating this frequently, the lubrication performance is lost in a short time. Also,
If the head slider (200) comes into contact with the magnetic disk (100), it will be destroyed by the impact, and the lubricating ability will gradually be lost if it is such as a graphite fluoride thin film having a graphite structure. become.

In addition, when a texture (700) having a height of 20 to 30 nm is formed on the magnetic recording layer (400), the head slider (200) is hindered by the texture (700) and
It is not possible to approach (400) below 20-30 nm.

[0009]

SUMMARY OF THE INVENTION The present invention is aimed at the development of a magnetic recording apparatus which enables a head slider to approach or slide into contact with a magnetic disk, which is hardly considered in such a conventional example. In addition, there is a need to develop a lubricant for a magnetic recording device capable of withstanding the severe friction conditions for a long period of time and a lubricating structure using the lubricant.

[0010]

A first aspect of the present invention relates to a basic lubricant coating material for a magnetic recording apparatus, wherein a single layer or multiple layers of hollow nanocarbon (6a) having a hydrophobic group is dispersed in a solvent. "Is".

In this case, the hollow nanocarbon (6a) is used alone as a material constituting the lubricating layer (6), and the magnetic disk (1) and the head slider (2) are contained in the lubricant coating material for the magnetic recording device. Hollow nanocarbon uniformly immersed in its surface
(6a) is applied with a solvent in which the solvent is dispersed, and then the solvent is volatilized, thereby magnetic disk (1) or head slider (2)
The hollow nanocarbon (6a) is evenly adhered to the protective layer (3) on the surface of. As the application method, besides "immersion", "spray" and other appropriate methods are used. In the case of FIG. 1, a lubricant layer (6) of hollow nanocarbon (6a) is formed on both the magnetic disk (1) and the head slider (2).
When it is necessary to reduce the thickness of (6) as much as possible, only one of them may be used. Generally, it is applied to the magnetic disk (1) as shown in FIG. The hollow nanocarbon (6a) includes a single-layered structure, a multi-layered structure, and a columnar or spherical structure, and any of them may be used.

As can be said throughout the present specification, it is necessary to make the thickness of the lubricating layer (6) as thin as possible, so that the lubricating layer (6) is a single layer of hollow nanocarbon (6a). Things are preferred. Since the hollow nanocarbon (6a) is dispersed in the solvent, the coating amount of the hollow nanocarbon (6a) can be freely changed only by selecting the dilution ratio. In addition, hollow nanocarbon (6a) dispersed in the solvent
(When the same kind approaches each other more than a certain distance, they repel each other, and the distance between them is kept almost constant.) So, apply this on the protective layer (3),
When the solvent evaporates, the hollow nanocarbon (6a) becomes a protective layer.
(3) It will be uniformly dispersed on the top.

Since the hollow nanocarbon (6a) itself does not have a hydrophobic group, it is hydrophobized by modification with the hydrophobic group. The modification method will be described later. This prevents water in the surrounding atmosphere from aggregating on the surface of the head slider (2) or the magnetic disk (1), and causes the head slider (2) to approach or slide against the surface of the magnetic disk (1). This prevents the head slider (2) from adhering to the magnetic disk (1) due to the surface tension of water.

The attachment of the hollow nanocarbon (6a) to the protective layer (3) depends on the physical adsorption force. The "lubrication mechanism" based on physical adsorption force is based on the fact that "defects" on the surface of the protective layer (3) and "defects" on the surface of the tubular or spherical hollow nanocarbon (6a) are "dangling". A "bond" is formed, and the hollow nanocarbon (6a) is fixed on the surface of the protective layer (3). This fixing is not permanent, and when a force larger than the bonding force is applied, the bond is released, and the hollow nanocarbon (6a) moves on the surface of the protective layer (3). Then, the “dangling bond” is formed again at the stop position of the moving destination and is fixed to the surface of the protective layer (3). As a result, the hollow nanocarbon (6a) is always present between the protective layer (3b) of the head slider (2) and the protective layer (3a) of the magnetic disk (1), which move relative to each other. Protective layer
(3b) prevents direct contact with the protective layer (3a) of the magnetic disk (1).

In the entire specification of the present specification, when a lower concept of a certain thing is expressed, it is expressed by adding a lowercase alphabet or a numerical suffix to the number itself. The types of hollow nanocarbon (6a) are tubular (6a1) as shown in FIG. 5 and spherical (6a2) as shown in FIG.
There is. The above two types include a single layer type and a multiple layer type. In addition, as a hydrophobic functional group, for example, an alkyl group (methyl group, ethyl group, butyl group, propyl group),
Examples include an alkoxyl group (a methoxy group, an ethoxy group, a propoxy group, a butyroxy group) and a benzyl group.

Claim 2 relates to another lubricating coating material for a magnetic recording device, characterized in that "fluorinated synthetic oil (6b) and hollow nanocarbon (6a) are dispersed in a solvent". .

In this case, when the hollow nanocarbon (6a) and the fluorinated synthetic oil (6b) are used as materials constituting the lubricating layer (6), the lubricity of the hollow nanocarbon (6a) is It is further reinforced by synthetic oil (6b). When applied to the application surface, the fluorinated synthetic oil (6b) fills the space between the hollow nanocarbons (6a) and, due to its hydrophobicity, the surrounding atmosphere on the surface of the head slider (2) or the magnetic disk (1). When the head slider (2) is brought close to or slid into contact with the surface of the magnetic disk (1), the head slider (2) adheres to the magnetic disk (1) due to the surface tension of the water, preventing the aggregation of water. Has been prevented.

The hollow nanocarbon (6a) used in claim 1 or 2 includes a tubular one (6a1) or a spherical one (6a2). The fact that there is a layer is as described above. Further, the lubricating layer (6) formed of the hollow nanocarbon (6a) and the fluorinated synthetic oil (6b) is used for the head slider (2) or the magnetic disk.
It is formed on one or both of (1). Generally, it is formed on the magnetic disk (1) side as shown in FIG. Also,
As shown in FIG. 3 (b), the fluorine-based synthetic oil (6b) has a case where the fluorine-based synthetic oil (6b) has no functional group, and a case where the fluorine-based synthetic oil (6b) has a functional group as shown in FIG. Can be FIG. 3 (e) shows that a single layer of hollow nanocarbon (6 a) is applied to the magnetic disk (1) side,
In this example, a fluorine-based synthetic oil (6b) fills the gap.

Claim 3 relates to the surface structure of the hollow nanocarbon (6a). "After coating, the surface of the hollow nanocarbon (6a) is free from defects that cause dangling bonds between the surface and the defects on the coated surface. Is formed. " The defect for forming a dangling bond is an energy (several tens of tens) lower than the energy at which carbon atoms constituting the hollow nanocarbon (6a) are beaten out (sputtered) by ions (for example, Ar) in the atmosphere. It is formed by irradiating Ar plasma with electron volts. As an example, claim 1
Alternatively, the hollow nanocarbon (6a) subjected to such a defect forming treatment is dispersed in the solvent 2.

[0020] Claim 4 relates to the hollow nanocarbon (6a).
(6a) has been taken out of Ketjen Black. " Hollow nanocarbon (6a) is not only one formed by arc discharge or laser, but also one obtained by appropriately cutting Ketjen Black, and sieving the required diameter and particle size from a group of cut pieces. You. diameter,
The sieving of the particle size will be described later.

A lubricating structure (see FIGS. 1 and 2) for a magnetic recording apparatus according to claim 5 is (a) rotatably disposed, and a magnetic recording layer (4) is formed on the surface thereof. A magnetic disk (1) whose surface is covered with a protective layer (3a), and (b) a magnetic head (2a) disposed close to or in contact with the protective layer (3a) of the magnetic disk (1). Equipped with at least a magnetic disk
(1) a magnetic recording device comprising a head slider (2) whose surface facing the protective layer (3a) is covered with a protective layer (3b), and (c) a magnetic disk (1) A lubricating layer (6) is formed on at least one of the protective layer (3a) or the protective layer (3b) of the head slider (2), and (d) the lubricating layer (6) is hydrophobized. It is characterized by being composed of hollow nanocarbon (6a).

In this case, the lubricating layer (6) is formed by using the lubricating coating material for a magnetic recording device according to claim 1, and the material of the lubricating layer (6) is hollow nanocarbon (6a). Will be used alone. The hollow nanocarbon (6a) used here includes a tubular one (6a1) or a spherical one (6a2). It is on the street.

In this case, the impact due to the collision with the protective layer (3) “generally made of diamond-like carbon or fluorinated diamond-like carbon” or the friction due to sliding on the protective layer (3) for protecting the magnetic recording layer (4) is reduced. Even if added, the hollow nanocarbon (6a) acts as a cushion material without being damaged, and absorbs the impact. Alternatively, when the head slider (2) slides in contact with the magnetic disk (1), the head slider (2) slides on the hollow nanocarbon (6a) on the protective layer (3) to greatly reduce the frictional force. In this case, the hollow nanocarbon (6a) may roll, which contributes to a drastic reduction in frictional force.

In addition, since the hollow nanocarbon (6a) is very tough in terms of strength, it is hardly damaged by the above-mentioned impact, sliding or rolling, and frequently repeated collision, sliding or rolling. The movement does not cause loss of lubricity.

The hollow nanocarbon (6a) has a protective layer (3)
With a “dangling bond”. When an external force (shock or sliding or rolling) greater than the bonding force of the dangling bond acts on the bonding portion, the bonding is released and the hollow nanocarbon (6a) is peeled off from the surface of the protective layer (3).
Will move and bind to the protective layer (3) at the destination.

The lubricating structure (see FIGS. 3 and 4) of the magnetic recording apparatus according to claim 6 is (a) rotatably provided, and a magnetic recording layer (4) is formed on the surface thereof. Surface is protective layer
(3a) magnetic disk (1) covered with, (b) disposed close to or in contact with the protective layer (3a) of the magnetic disk (1),
Equipped with a magnetic head (2a) and at least a magnetic disk (1)
A head slider (2) whose surface facing the protective layer (3a) is covered with a protective layer (3b), and (c) a protective layer of the magnetic disk (1). (3a) or at least one of the protective layer (3b) of the head slider (2) is a lubricating layer.
(6), and (d) the lubricating layer (6) is composed of a mixture of a fluorinated synthetic oil molecule (6b) and a hollow nanocarbon (6a).

In this case, the "interaction" protects the fluorine-based synthetic oil molecule (6b) and the hollow nanocarbon (6a) by mixing them to some extent alternately without being close to each other, although they are random. It is considered that they are attached side by side on the layer (3). Since the fluorine-based synthetic oil molecule (6b) is thinner than the hollow nanocarbon (6a), it is considered that the fluorine-based synthetic oil molecule (6b) is attached to the protective layer (3) so as to fill the space between the hollow nanocarbons (6a).

Also in this case, it is preferable to make the gap between the head slider (2) and the magnetic disk (1) as small as possible, so that the lubricating layer (6) is preferably a single layer of hollow nanocarbon (6a). . In this case, as shown in FIG. 3, a lubricating layer (6) is formed on the magnetic disk (1) side so that the fluorine-based synthetic oil molecule (6b) exists between the single-layer hollow nanocarbon (6a). It is common to do.

The attachment form of the fluorine-based synthetic oil molecule (6b) to the protective layer (3) is as follows: (a) As shown in the partially enlarged drawings (b) of FIGS. (6b) is mixed between the hollow nanocarbons (6a), and (b) as shown in the partially enlarged drawings (c) of FIGS.
A polar group (functional group) having an affinity for the protective layer (3) is bonded to one end of b), and the polar group is attached so as to extend uniformly from the surface of the protective layer (3). There is a case where a chain type fluorine-based synthetic oil molecule (6b) is randomly entangled between the homogeneous layers (this portion is regarded as a non-uniform layer).

Examples of the fluorine-based synthetic oil molecule (6b) include perfluoropolyether and polyalphaolefin (PAO = POL).
Y-α-OLEFIN), polybutene (PBT = POLYBUTENE), polyoxypropylene monoether (POP = POLYOXYPROPYLENEMONOE)
HTER), MALEIC ANHYDRIDE MODIFIED POLYBUTENE (MPBT = MALEIC ANHYDRIDE MODIFIED POLYBUTENE),
An example thereof is PFPE DIOL.

As a function of the fluorine-based synthetic oil molecule (6b), the hydrophobicity of the fluorine-based synthetic oil molecule (6b) prevents the surrounding water molecules from adsorbing to the protective layer (3), and at the same time, provides excellent lubrication. Greatly reduces frictional force. Fluorine-based synthetic oil molecule (6b)
The greatest advantage of simultaneously using the hollow nanocarbon (6a) and the hollow nanocarbon (6a) is that the hollow nanocarbon (6a) directly carries the external force applied at that time against To prevent the decomposition of the fluorine-based synthetic oil molecule (6b) by applying the external force directly to the easy-to-use fluorine-based synthetic oil molecule (6b) and to prolong the lubrication performance of the fluorine-based synthetic oil molecule (6b) The point is that it becomes possible. Of course, hydrophobic hollow nanocarbon (6a) may be used.

The lubricating structure of the magnetic recording device according to claim 7 is the same as the hollow nanocarbon (6a) according to claim 5 or 6.
Are spherical ". Hollow nanocarbon
If (6a) is spherical, elastic nano hollow carbon (6a
2) easily rolls on the protective layer (3), and the coefficient of friction when the head slider (2) slides on the magnetic disk (1) can be further reduced.

Further, the elasticity can reduce the impact at the time of collision or sliding of the head slider (2) against the protective layer (3), and the lubrication performance can be maintained even when used alone. When used together with the fluorinated synthetic lubricating oil (6b), not only can the lubricating performance of the fluorinated synthetic lubricating oil (6b) be fully utilized, but also the deterioration of the fluorinated synthetic lubricating oil (6b) Can be prevented.

The lubricating structure of the magnetic recording apparatus according to the eighth aspect is the hollow nanocarbon (6a) according to the fifth or sixth aspect.
Is tubular ". Hollow nanocarbon
When (6a) is tubular as shown by (6a1), the hollow nanocarbon (6a) itself is rich in elasticity as described above, so that the head slider (2) collides with the protective layer (3) or slides as described above. The shock at the time can be reduced, and when used with the fluorine-based synthetic lubricating oil (6b), deterioration of the lubricating performance can be prevented.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. A first invention relates to a lubricating coating material for a magnetic recording device, and a second invention relates to a lubricating structure of a magnetic recording device using the lubricant. First, a lubricating coating material for a magnetic recording device will be described.

"First Embodiment of Lubricating Coating Agent for Magnetic Recording Apparatus" In this case, only hollow nanocarbon (6a) is used as an active ingredient, and "dangling bond" is performed by utilizing the surface defect on the coated surface. In the case of bonding, the hollow nanocarbon (6a) having such an action is uniformly dispersed in the solvent. The solvent is volatile, such as benzene,
Toluene, phenol, nitrobenzene, florinate
(Trade name of 3M), Fomblin (trade name of Montedison) or pyridine. The dilution ratio depends on the thickness of the lubricating layer (6) formed on the protective layer (3) of the magnetic disk (1), but here, a protective layer (3) consisting of a single layer of hollow nanocarbon (6a) is planned. Therefore, the dilution ratio is, for example, such that the content of the hollow nanocarbon (6a) is about 0.1 to 0.01% by weight.

As the hollow nanocarbon (6a), a spherical thing (6a2) called fullerene, a tubular thing (6a1) obtained by growing the same, or carbon black (or Ketjen black) is appropriately cut. , Whose diameter and length are adjusted to some extent are used. The hollow nanocarbon (6a) may be a single layer or a multi layer. In the present invention, any one may be used.

[0038] The diameter is 2
About 1.0 to 5.0 nm or 2 to 30 n depending on the reaction temperature.
There are various types such as m. In the case of a single layer, for example, those having an average diameter of 0.78, 0.9, 1.1 nm and the like are available. In the case of a tube, its length depends on the degree of growth, but 0.1
2020 μm. Although the Young's modulus of the tubular nanocarbon (6a1) is not always clear, the Young's modulus measured with an AFM probe is said to be about 1.28 TPa, which is about twice that of the ultrahigh modulus carbon fiber having a Young's modulus of 700 GPa.

Carbon black (or Ketjen black) is formed by connecting spherical fine carbon innumerably to form a lump. As a method of extracting hollow nanocarbon (6a) having a desired shape from such carbon black, a plasma treatment of a carbon black lump can be mentioned. That is, when plasma irradiation is performed on the carbon black lump, the weak portion is cut and scattered. When this is blown in a certain direction in an inert gas, large lumps fall close to each other and light ones fly far away. Particles having a particle size of 2 to 4, 5 to 7, 8 to 10, and 11 to 13 nm, particularly 1.0 to 1.4 nm when a microstructure is developed can be selected.

Since the hollow nanocarbon (6a) does not show hydrophobicity as it is, it cannot be dispersed in a hydrophobic solvent as it is. Therefore, a hydrophobic treatment is performed. As the hydrophobic treatment, for example, hollow nanocarbon (6a)
Is cleaned and activated with Ar or Ar + H ₂ plasma. Subsequently, plasma treatment was performed in an Ar + methane atmosphere to attach a methyl group (of course, it is possible to attach another hydrophobic group by changing the atmosphere) to the surface of the hollow nanocarbon (6a).

Alternatively, hollow nanocarbon (6a) may be
Expose for 40 hours or more in a reduced-pressure methane atmosphere at about ℃ and perform plasma discharge in the reduced-pressure methane atmosphere to attach a methyl group (of course, another hydrophobic group by changing the atmosphere) to the surface of the hollow nanocarbon (6a). Is possible.) As a result, it becomes hydrophobic and can be uniformly dispersed in a hydrophobic solvent. Hollow nanocarbon (6
The bonding of a) by "dangling bond" is performed by irradiating the surface of the hollow nanocarbon (6a) with plasma with low energy.

The magnetic recording device to which the lubricant is applied is as follows:
It is a magnetic disk (1) or a head slider (2). The magnetic disk (1) has a magnetic storage layer (4) formed on a substrate layer (5) as shown in FIG. 1, and the magnetic storage layer (4) has a protective layer (3).
Covered in a). The thickness of the protective layer (3a) is 5 to 10 nm
And made of diamond-like carbon or fluorinated diamond-like carbon.

On the other hand, the head slider (2) is attached to a cantilever spring (not shown), and a magnetic head (2
a) is installed. Then, a protective layer (3b) made of diamond-like carbon is formed on the surface on the side of the magnetic disk (1) to protect the magnetic head (2a). When simply referred to as a protective layer in this specification, the code is (3),
When discriminating between the magnetic disk (1) side and the head slider (2) side, (3a) and (3b) are used.

Next, the hollow nanocarbon (6a) is coated with the protective layer (3).
Will be described with reference to the case of bonding with a “dangling bond”. A magnetic disk (1) or a head slider (2) having a dust-free surface state is added to the lubricant coating material for a magnetic recording device of the first embodiment in which the hollow nanocarbon (6a) is uniformly dispersed in a solvent. Is dipped or sprayed, and the solvent is uniformly applied. Thereafter, when the solvent is evaporated, only the hollow nanocarbon (6a) remains in a state of being uniformly dispersed on the protective layer (3).

The hollow nanocarbon (6a) is in direct contact with the surface of the protective layer (3), and a bond extending from a “defect” existing on the surface of the protective layer (3) and the hollow nanocarbon (6a). Bonds extending from “defects” formed on the surface are combined with each other to form “dangling bonds”, and fix the hollow nanocarbon (6a) on the protective layer (3).

Next, the lubricating action of the present invention will be described.
When the magnetic disk (1) is stopped, the head slider (2)
Is stationary on the protective layer (3a) via the hollow nanocarbon (6a). When the magnetic disk (1) starts to rotate from this state, the head slider (2) slides on the protective layer (3a), or moves relatively while slightly floating and magnetically stores in the magnetic head (2a). Read the information recorded in layer (4). (Of course, information may be recorded on the magnetic storage layer (4) by the magnetic head (2a).) The rotation speed of the magnetic disk (1) depends on the storage density of the magnetic disk (1) or the speed of taking out information. When the rotation speed is sufficiently low, the head slider (2) slides on the magnetic disk (1). Will do. However, the contact frequency increases dramatically compared to the conventional example.

When the head slider (2) slides on the protective layer (3a), microscopically, the protective layer of the head slider (2)
(3b) and the contact between the protective layer (3a) of the magnetic disk (1), which means that (preferably a single layer) hollow nanocarbon (6a) is interposed, and the protective layer (3a ) (3b) prevents direct contact between each other. The hollow nanocarbon (6a) is very light, strong and elastic, and exhibits excellent lubricity without being damaged by the sliding of the head slider (2) or the impact at the time of contact.

That is, the diameter of the head slider (2) is about 1.0 to 1.4 nm, is not damaged by collision or sliding of the head slider (2), has a sufficiently high strength and elasticity, and bends or dents during rolling. The head slider (2) slides on the protective layer (3) by using the hollow nanocarbon (6a) as a lubricating layer (6) that does not return to its original shape and break even if there is In this case, the coefficient of friction is greatly reduced. At the same time, the aging of the lubricity is very small due to the toughness of the hollow nanocarbon (6a).

At this time, if the external force applied to the hollow nanocarbon (6a) is larger than the bonding force due to the “dangling bond”, the bond is disengaged and the hollow nanocarbon (6a) moves. The "dangling bond" formed by the bonds extending from the "defect" is formed again, so that the "dangling bond" does not separate from the protective layer (3). Rolling property is spherical nanocarbon
It is considered that (6a2) is superior to the tubular nanocarbon (6a1). Protective layer (3) is tubular nanocarbon
(6a1) or the spherical nanocarbon (6a2) alone, or both may be mixed.

When such hollow nanocarbon (6a) is used, the collision or sliding of the head slider (2) is directly received by the hollow nanocarbon (6a), and the texture (700 It is not necessary to use). Therefore, the head slider (2) is moved to the surface of the magnetic disk (1), that is, the protective layer, up to the diameter of the hollow nanocarbon (6a) as the minimum gap.
It can be close to (3).

Since the hollow nanocarbon (6a) has a hydrophobic group bonded to its surface by a hydrophobic treatment,
There is no possibility that moisture in the surrounding atmosphere is attracted and moisture does not enter between the protective layers (3a) and (3b) and fix the head slider (2) to the magnetic disk (1) by its surface tension.

In the above case, the fluorination of the hollow nanocarbon (6a) is performed as follows. The atmosphere of the reactor was changed to a fluorine gas atmosphere (argon or helium mixed with a hydrocarbon gas containing fluorine).
(6a), and covalently bonding fluorine to carbon. In the above case, the lubrication layer (6) is formed only on the magnetic disk (1) side as shown in FIG.
The head slider (2) and the magnetic disk (1) as shown in FIG.
(2) It may be formed only on the side.

The second embodiment of the lubricating coating material for a magnetic recording apparatus is such that the lubricating property of the hollow nanocarbon (6a) is
To further reinforce by b), hollow nanocarbon (6a)
And a fluorine-based synthetic oil (6b) dispersed in a solvent. The fluorine-based synthetic oil molecule (6b) used in this example is perfluoropolyether. Its average molecular weight is between 1500 and 6000.

In the above case, the case where the hollow nanocarbon (6a) is made hydrophobic is also included. In any case, due to the `` interaction '', the fluorine-based synthetic oil molecule (6b) and the hollow nanocarbon (6a) are random but the same kind are mixed alternately to some extent without being close to each other, and the protective layer (3)
It is considered that they adhered side by side.

Also in this case, it is preferable to make the gap between the head slider (2) and the magnetic disk (1) as small as possible, so that the lubricating layer (6) is preferably a single layer of hollow nanocarbon (6a). . For this purpose, it is preferable to form the lubricating layer (6) only on the magnetic disk (1) side as shown in FIG. 3, but it is preferable to form the lubricating layer (6) on both the head slider (2) and the magnetic disk (1) as shown in FIG. Or a head slider (not shown).
(2) It may be formed only on the side. Further, since the diameter of the fluorine-based synthetic oil molecule (6b) is smaller than the diameter of the hollow nanocarbon (6a), it enters between the hollow nanocarbons (6a) and encloses the hollow nanocarbon (6a). As a result, the lubricating properties of the fluorinated synthetic oil molecule (6b) are exhibited, but the external force applied to the contact surface is carried by the hollow nanocarbon (6a) and serves as a cushion. Does not generate heat.

As a result, since the external force is not directly applied to the fluorine-based synthetic oil molecule (6b) and there is no damage due to heat, the slidable contact or the presence of frequently repeated impacts causes severe use conditions. Nevertheless, the fluorine-based synthetic oil molecule (6b) does not deteriorate over a long period of time. Then, as shown in FIGS. 3 and 4 (b), the fluorine-based synthetic oil molecule (6b) is simply added to the fluorine-based synthetic oil molecule (6b) to form a non-uniform layer as a whole. As shown in (c) and (d) of FIGS. 3 and 4, a functional group is modified on the fluorine-based synthetic oil molecule (6b),
In some cases, a part thereof adheres to the protective layer (3) to form a uniform layer, and the remainder forms a non-uniform layer that moves freely.

In the case of a lubricant coating agent, hollow nanocarbon (6a)
And the fluorinated synthetic oil (6b) are uniformly dispersed in the solvent by the interaction, and these dispersion solvents are applied to the protective layer (3) of the magnetic recording device by an appropriate method such as application or spraying,
Subsequently, only the solvent is evaporated. As a result, the hollow nanocarbon (6a) and the fluorine-based synthetic oil molecule (6b) are dispersed on the protective layer (3) in a state of being mixed with each other. In this case, the diameter of the fluorinated synthetic oil molecule (6b) is hollow nanocarbon (6a)
Since the diameter is much smaller than the diameter of the carbon nanoparticle, the mass of the fluorinated synthetic oil molecule (6b) is interposed between the hollow nanocarbons (6a) as described above, thereby reinforcing the hydrophobicity and lubricity.

[0058]

According to the present invention, since the hollow nanocarbon is used as the lubricant, the texture can be made unnecessary, and the head slider can be brought as close as possible to the surface of the magnetic disk or can be slid. It is possible to cope with high integration of the magnetic disk. Further, when used together with a fluorinated synthetic oil, the hollow nanocarbon serves as a buffer, preventing deterioration of the fluorinated synthetic oil and maintaining a long-term lubricating effect.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the operation of the present invention in a case where only hollow nanocarbon is used as a lubricant and this is used only on the magnetic disk side.

FIG. 2 is a diagram illustrating the operation of the present invention in a case where only hollow nanocarbon is used as a lubricant and the lubricant is used for both a head slider and a magnetic disk.

FIG. 3 is an explanatory view of the operation of the present invention in a case where hollow nanocarbon and a fluorine-based synthetic oil are used as a lubricant and the lubricant is used only on the magnetic disk side.

FIG. 4 is a diagram illustrating the operation of the present invention when hollow nanocarbon and a fluorine-based synthetic oil are used as a lubricant and the lubricant is used for both a head slider and a magnetic disk.

FIG. 5 is an imaginary front view of a tubular hollow nanocarbon used in the present invention.

FIG. 6 is an imaginary front view of a spherical hollow nanocarbon used in the present invention.

FIG. 7 is an explanatory view of a conventional operation.

[Explanation of symbols]

 (1) Magnetic disk (2) Head slider (3) Protective layer (3a) Protective layer on magnetic disk side (3b) Protective layer on head slider side (4) Magnetic storage layer (5) Substrate layer (6) Lubrication layer ( 6a) Hollow nanocarbon (6a1) Tubular hollow nanocarbon (6a2) Spherical hollow nanocarbon (6b) Fluorine-based synthetic oil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G11B 5/187 G11B 5/187 K 5/60 5/60 Z // C10N 20:06 40:18 50: 02 (72) Inventor Ryuji Igarashi F-term in Nova Science Co., Ltd. 1-1-1 Azabudai, Minato-ku, Tokyo 4H104 AA04A BD05A CD04A EA07A PA16 QA08 5D006 AA01 AA02 FA06 5D042 NA01 PA10 QA03 RA02 SA02 5D111 FF FF33 GG09 JJ03 KK08

Claims (8)

[Claims] 1. A lubricating coating material for a magnetic recording device, wherein a single-layer or multiple-layer hollow nanocarbon having a hydrophobic substituent is dispersed in a solvent. 2. A lubricating coating material for a magnetic recording device, wherein a fluorine-based synthetic oil and hollow nanocarbon are dispersed in a solvent. 3. A magnetic recording, characterized in that a defect which generates a dangling bond between the surface of the hollow nanocarbon according to claim 1 and a defect on the coated surface after coating is formed. Lubricant coating agent for equipment. 4. A lubricating coating agent for a magnetic recording device, wherein the hollow nanocarbon according to claim 1 is extracted from Ketjen Black. 5. A magnetic recording apparatus comprising: a rotatable magnetic disk; and a head slider provided with or adjacent to a protective layer of a magnetic recording layer on the surface of the magnetic disk and having a magnetic head mounted thereon. A lubricating layer is formed on at least one of the magnetic recording layer and the head slider of the disk, and the lubricating layer is formed of hollow nanocarbon having a hydrophobic substituent. Lubrication structure. 6. A magnetic recording apparatus comprising: a rotatable magnetic disk; and a head slider mounted on or near a magnetic recording layer of the magnetic disk and having a magnetic head mounted thereon. A lubricating layer is formed on at least one of the magnetic recording layer and the head slider, and the lubricating layer is composed of fluorine-based synthetic oil molecules and hollow nanocarbon. Construction. 7. A lubricating structure for a magnetic recording apparatus, wherein the hollow nanocarbon according to claim 5 is spherical. 8. A lubricating structure for a magnetic recording device, wherein the hollow nanocarbon according to claim 5 is tubular.