JPH0944969A - Magnetic disk holding member and magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove the static electricity of a magnetic disk by providing the inside and outside edge parts of a holding member with curved surfaces and coating the inner peripheral surface of the contact surface with the magnetic disk with a conductive ceramic film. SOLUTION: A spacer 11 consists of an annular body 112 and the tapered surfaces or curved surfaces having a width of 0.04 to 0.5mm are formed on the inside and outside edges 114a, 114b thereof. The contact surface 113 of the spacer 11 has surface roughness to prevent the spacer from turning accompanying the high-speed rotation of the magnetic disk and has a prescribed flatness to obviate the occurrence of a strain in the disk. The entire surface of the annular body 112 is coated with the conductive ceramic film 115 having a specific volumetric resistance value of <=1×10<7> Ω.cm and a coefft. of thermal expansion of 6 to 10×10<-6> / deg.C at a film thickness in a range of 0.1 to 3μm. Consequently, the efficient removing of the static electricity electrified on the magnetic disk is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk holding member for holding a magnetic disk in a predetermined position, and a magnetic disk device in which one or more magnetic disks are held in a hub using the magnetic disk holding member. Is.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, in a magnetic disk device, a plurality of magnetic disks 15 and spacers 11 are alternately inserted into a hub 14 fixed to a rotary shaft 13, and finally a shim 10 is inserted. And press it with clamp 12, screw 1
It was fixed by tightening with 6.
The magnetic disk 15 is rotated by the rotation of the rotary shaft 13.
While rotating the magnetic head 17, the magnetic head 17
By moving on the surface of the magnetic disk in a non-contact state, information is written or read at a predetermined position of the magnetic disk 15.

Further, in recent years, in such a magnetic disk device 50, the distance between the magnetic head 17 and the magnetic disk 15 has been minimized and the magnetic disk 15 has a higher plane as the information density and capacity have increased. Therefore, it is required to make the magnetic disk 15 smoother and smoother. Therefore, there has been proposed a magnetic disk 15 made of ceramics or glass which can very effectively obtain the surface strength and smoothness of the magnetic disk 15. Spacer 11 and shim 1 for fixing and holding the disk 15
The holding members such as 0 and the clamp 12 were made of ceramics or glass in order to prevent the distortion of the magnetic disk 15 due to the difference in thermal expansion (Japanese Patent Publication No. 5-80).
745 and JP-A-61-148667).

However, since the ceramics and glass constituting the holding member are generally insulating materials,
It has been known in recent years that when the magnetic disk 15 is held by these holding members, the magnetic disk 15 is charged, noise is generated during reading or writing of information, and the recorded contents may be destroyed. For this reason, there has been one in which a magnetic disk 15 is prevented from being charged by using a holding member in which a contact surface with the magnetic disk 15 is coated with a metal film such as aluminum or zinc (JP-A-2-226566).
Issue).

[0005]

However, in the holding member having the contact surface covered with the metal film, the difference in thermal expansion between the metal film and the ceramics or glass forming the base is large.
There is a problem that the flatness of the contact surface is impaired by the heat generated by the high speed rotation. Therefore, when the magnetic disk device 50 is configured using this holding member, the magnetic disks 15 are distorted and the parallelism between the magnetic disks 15 is impaired, so that the flying height of the magnetic head 17 is reduced. However, in some cases, the magnetic head 17 may come into contact with the magnetic disk 15 and damage the magnetic disk 15.

In addition, the coated metal film may be peeled off due to the difference in thermal expansion from the ceramics or glass forming the substrate, and as a result, static electricity charged on the magnetic disk 15 cannot escape.

The metal film is formed in a thin film so as not to impair the flatness of the contact surface, but scratches occur between the magnetic disk 15 and the holding member due to high speed rotation, and the hardness is small. Since the metal film is worn or peeled off, there is a fear that static electricity charged on the magnetic disk 15 cannot be released.

Further, when the inner and outer edges of the holding member are sharp edges, the film thickness of the metal film coated on the edges becomes thin, and in some cases, disconnection occurs and static electricity cannot escape. was there. In addition, since the ceramics and glass that constitute the holding member are brittle materials, if the edge portion is a sharp edge, there is a risk of chipping due to stress during clamping, and the fragments float above the magnetic disk 15 and above it. If it enters the gap between the magnetic head 17 and the magnetic head 17, the magnetic disk 15 may be scratched or the magnetic head 17 may be damaged.

Therefore, in the magnetic disk device 50 holding the magnetic disk 15 by these holding members, it is difficult to realize a sufficiently high density and large capacity of information, and the magnetic disk 15 is charged with static electricity. However, there is a risk that noise may occur during reading or writing of information and the recorded contents may be destroyed.

[0010]

In view of the above problems, a shim made of ceramics or glass,
Of holding members such as clamps and spacers, a tapered surface or a curved surface having a width of 0.04 to 0.5 mm is provided on the inner and outer edge portions of the holding member, and at least the contact surface with the magnetic disk and the inner peripheral surface. Thickness of 0.1 to 3 μm
It is characterized in that it is coated with a conductive ceramic film.

Further, according to the present invention, a hub made of a conductive material is fixed to a rotating shaft, and a ring body made of ceramics or glass is used.
It has a taper surface or curved surface of 0.5 mm, and has a film thickness of 0.1 to at least on the contact surface with the magnetic disk and the inner peripheral surface.
A magnetic disk device is constructed by holding one or a plurality of magnetic disks made of ceramics or glass via a spacer and / or a shim covering a conductive ceramic film of 3 μm.

Furthermore, the present invention provides TiC, TiN, ZrN, HfC, TaC, Z as the conductive ceramic film.
It is coated with one of rC, WC, VC, NbC, TiB ₂ , and In ₂ O ₃ .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

1 to 3 are views showing a holding member according to the present invention, FIG. 1 (a) is a perspective view of a spacer 11, and FIG.
Is a sectional view thereof, FIG. 2A is a perspective view of the shim 10, and FIG.
Is a sectional view thereof, FIG. 3 (a) is a perspective view of the clamp 12 ',
(B) is the sectional view. First, the spacer 11 shown in FIG. 1 is a ring body 11 made of ceramics or glass.
2, the inner and outer edge portions 114a and 114b are formed with a tapered surface (including a C surface) or a curved surface.
The contact surface 113 of the spacer 11 has a center line average roughness (Ra) of 0.1 to 2.0 μm in order to prevent the fixed magnetic disk from rotating due to high speed rotation. At the same time, the flatness of the contact surface 113 is set to 3 μm or less to prevent the magnetic disk from being distorted when fixed, and the upper and lower contact surfaces 113 to hold the magnetic disk at a predetermined position. Has a parallelism of 5 μm or less. The conductive ceramic film 1 having a volume resistivity of 1 × 10 ⁷ Ω · cm or less and a thermal expansion coefficient of 6 to 10 × 10 ⁻⁶ / ° C. is formed on the entire surface of the ring body 112.
15 is coated in a film thickness range of 0.1 to 3 μm.

As shown in FIG. 2, the shim 10 has the same shape as the spacer 11 and is slightly thin.

The clamp 12 'shown in FIG. 3 is a disk-shaped plate 12 made of ceramics or glass.
2 ', in the center of one surface, a recess 127' for engaging the tip portion of the hub and a screw hole 12 for fixing to the hub.
8'is provided, and the inner and outer edge portions 1 of the plate-like body 122 'are provided.
24'a and 124'b are formed with tapered surfaces (including C surface) or curved surfaces.

Further, the contact surface 12 of the clamp 12 'is
3 ′ has a center line average roughness (Ra) of 0.1 to 2.0 μm in order to prevent the magnetic disk from being distorted and to prevent the disk from rotating like the spacer 11. The flatness is 3 μm or less. And
The volume resistivity value is 1 × 10 on the entire surface of this plate 122 ′.
⁷ Ω · cm or less and a thermal expansion coefficient of 6 to 10 × 10 ^-6
The conductive ceramic film 125 'having a thickness of 0.1 / ° C.
It is coated in the range of 3 μm.

As described above, according to the present invention, since the base body constituting the holding member such as the shim 10, the spacer 11 and the clamp 12 'is formed of ceramics or glass, the contact surfaces 103, 113, 123' are formed. It is very smooth and can be finished with excellent flatness. In addition, the present invention is at least the contact surfaces 103, 113, 12
3'and the inner wall surfaces 106, 116, 126 'are coated with high-hardness conductive ceramic films 105, 115, 125', and the thickness thereof is as thin as 0.1 to 3 .mu.m. Therefore, the contact surface 103, It is possible to make the surface excellent in wear resistance without impairing the flatness and parallelism of 113 and 123 '. Moreover, the conductive ceramic films 105, 11
Since 5, 125 'have a volume resistivity value of 1 × 10 ⁷ Ω · cm or less, static electricity charged on the magnetic disk can be efficiently released.

In the present invention, the coefficient of thermal expansion is 6-10.
Conductive ceramic films 105, 11 having a density of × 10 ^-6 / ° C.
Since it is coated with 5, 125 ', it is close to the coefficient of thermal expansion of the ceramics or glass that forms the base, and the coefficient of thermal expansion of the ceramics or glass that forms the magnetic disk (8.0 to 10.0x10). ^-6 / ° C.), it is possible to prevent the conductive ceramic films 105, 115, 125 from peeling or deforming due to heat associated with high-speed rotation, and to hold the magnetic disk with extremely high plane accuracy. .

Further, according to the present invention, since the taper surface or the R surface is formed on the inner and outer edge portions 104, 114, 124 'of each holding member, it is possible to prevent chipping at the time of clamping and also to prevent the edge portions 104, 114 from being formed. , 124 'can be ensured and the thickness of the conductive ceramic films 105, 115, 125' can be secured to prevent disconnection.

Next, FIG. 4 shows a magnetic disk device 50 holding the glass magnetic disk 15 having a magnetic film by the holding member.

A hub 14 having a metal-made substantially cylindrical body 14 having a flange portion 14a is fixed to the rotary shaft 13, and the hub 1 is fixed.
4, a plurality of magnetic disks 15 and the spacers 11 shown in FIG. 1 are alternately inserted into the flange portion 14a of FIG.
After inserting the shim 10 shown in, press it with a clamp 12 made of metal or ceramics such as alumina.
The magnetic disk 15 is fixed by fastening the clamp 12 to the hub 14 with the screw 16.

A magnetic disk device 50 according to the present invention includes a magnetic disk 15 and a holding member (spacer 11, shim 10).
Since the coefficients of thermal expansion are similar, there will be no inconvenience due to the difference in thermal expansion even if the temperature becomes high during high speed rotation. Therefore, the flying height of the magnetic head 17 with respect to the magnetic disk 15 can be made extremely small, and the information recording density can be increased. Moreover, since the holding members (the spacers 11 and the shims 10) have conductivity, the static electricity charged on the magnetic disk 15 can be released through the metal hub 14 and the rotary shaft 13, and the recorded contents It can be prevented from being destroyed.

As the above-mentioned magnetic disk 15, a glass glaze layer may be formed on the surface of a ceramic substrate and a magnetic film may be coated on the glass substrate instead of the glass substrate.

Further, in the magnetic disk device 50 shown in FIG. 4, the shim 10 is held between the uppermost magnetic disk 15 and the clamp 12, but as another embodiment, the clamp 12 is arranged at the uppermost part. The magnetic disk 15 may be directly held in contact with the magnetic disk 15, and in this case, by using the clamp 12 'shown in FIG.
Can be held, and static electricity charged on the uppermost magnetic disk 15 can be effectively released.

Further, as another example of the magnetic disk device 50, the flange portion 14a of the hub 14 and the magnetic disk 15 are provided.
The spacer 11 disposed between the magnetic disk 15 and the spacer may be removed by directly abutting and holding the spacer.
In order to eliminate the difference in thermal expansion between the hub and the substrate, it is effective to use the hub 14 whose base is made of ceramics or glass and whose surface is coated with a conductive ceramic film.

By the way, the spacer 11, the shim 10,
As the material of the base body forming the holding member such as the clamp 12, ceramics or glass having a thermal expansion coefficient of 20 × 10 ⁻⁶ / ° C. or less, preferably 12 × 10 ⁻⁶ / ° C. or less can be used. As ceramics, alumina ceramics, zirconia ceramics, silicon carbide ceramics, silicon nitride ceramics, Al ₂ O ₃
-TiC ceramics, forsterite ceramics, etc. are suitable.

In particular, these ceramics have a coefficient of thermal expansion in the above range and a large specific rigidity, so that the contact surfaces 103, 11 do not deform during clamping.
It is possible to finish 3,123 'with extremely smooth and excellent plane accuracy.

Then, depending on the material of the magnetic disk 15, a material having a thermal expansion coefficient close to that of the material of the holding member may be used. For example, when the magnetic disk 15 made of ceramic is used, ceramic having a coefficient of thermal expansion of 10 × 10 ⁻⁶ / ° C. or less may be used as the holding member, and similarly, glass (coefficient of thermal expansion of 8.0 to 9 × 10) is used. ^-6 /
When the magnetic disk 15 made of (.degree. C.) is used, forsterite ceramics or glass having a thermal expansion coefficient of 8.0.times.10.sup.- ⁶ / .degree. C. or more may be used as the holding member.

Further, the inside and outside edge portions 10 of the holding member such as the spacer 11, the shim 10 and the clamp 12 described above.
4, 114, 124 'are formed with a tapered surface (including C surface) or a curved surface to prevent chipping due to stress during clamping. If the tapered surface or curved surface is too small, the edge portion 104, A disconnection occurs at 114 and 124 ', and conduction is lost.

Therefore, in the present invention, the inner and outer edge portions 104, 114, 124 'of the holding member are formed with tapered surfaces or curved surfaces having a width of 0.04 mm or more.

That is, the edge portions 104, 114, 124 '
As described above, when the width of the tapered surface or the curved surface formed in the above is less than 0.04 mm, the edge portion 104 of the holding member,
Since 114 and 124 'have sharp edges, the conductive ceramic films 105, 115 and 125' coated on them are sharp edges.
This is because there is a possibility that the thickness of the film becomes thin and the wire is broken. However, if the width of the tapered surface or the curved surface is larger than 0.5 mm, the contact area of the contact surfaces 103, 113, 123 ′ with the magnetic disk 15 becomes small, so that the magnetic disk 15 is distorted during clamping. , 0.04 to the inner and outer edge portions 104, 114, and 124 'of the holding member.
It is desirable to form a tapered surface or a curved surface in the range of 0.5 mm.

The width of the tapered surface or the curved surface referred to in the present invention will be explained by taking the spacer 11 as an example. As shown in the enlarged view of the main portion of FIG. 5, the end surface of the edge portion 114a on the contact surface 113 side. Is the width L from.

Of these holding members, at least the contact surfaces 103, 113, 123 have center line average roughness (R
It is necessary that the surface roughness of a) is 0.1 to 2.0 μm. This is because when the center line average roughness (Ra) of the contact surfaces 103, 113, 123 'is less than 0.1 μm, the coated conductive ceramic films 105, 115, 125' are adhered with a sufficient anchor effect. And the conductive ceramic films 105, 115, 12
This is because the surface of 5'becomes too smooth and slips on the magnetic disk 15 with high-speed rotation. Conversely, the center line average roughness (Ra) of the contact surfaces 103, 113, 123 'is 2 If it is larger than 0.0 μm, the flatness of the magnetic disk 15 is impaired and the magnetic disk 15
Because it will scratch the.

On the other hand, as the conductive ceramic films 105, 115, 125 ′ covering the holding member, TiC, Ti
N, ZrN, HfC, TaC, ZrC, WC, VC, N
One of bC and TiB ₂ is suitable.

These conductive ceramic films 105, 1
As shown in Table 1, Nos. 15 and 125 ′ have a volume specific resistance value of less than 1 × 10 ⁷ Ω · cm, the magnetic disk 15
The static electricity charged in the inside can be effectively removed, and further, the coefficient of thermal expansion is about ⁶ to 10 × 10 ⁻⁶ / ° C., and the ceramics or glass constituting the holding member, the ceramics constituting the magnetic disk 15, or the like. Since the coefficient of thermal expansion of glass is the same as or similar to that of glass, the conductive ceramic films 105, 115, 125 ′ are heated by the heat accompanying high-speed rotation.
The magnetic disk 15 can be held with very high plane accuracy without peeling or deformation. In addition to the above-described conductive ceramic films 105, 115, 125 ′, for example, ITO made of In ₂ O ₃ doped with Sn is used.
(Indium Tin Oxide) film or the like can also be used.

However, the conductive ceramic film 1 to be coated
It is important that the film thicknesses of 05, 115 and 125 'are provided in the range of 0.1 to 3.0 μm.

When the film thickness is less than 0.1 μm,
High hardness conductive ceramics film 105, 115, 12
This is because even if it is 5 ', it may be worn, and conversely,
When the film thickness becomes thicker than 3.0 μm, the contact surfaces 103, 11
This is because the flatness of 3,123 ′ cannot be set to 3 μm or less.

The conductive ceramic films 105, 1
15, 125 'may be formed by a usual film forming means such as a PVD method or a CVD method, but when the glass-made holding member is coated with the conductive ceramic film 105, 115, 125', it can be formed at a low temperature. If the PVD method is used, it is optimum without impairing the flatness of the holding member.

[0040]

[Table 1]

[0041]

【Example】

(Experimental Example 1) Here, the spacer 11 shown in FIG. 1 was prepared, and the degree of contact and the flatness of the conductive ceramic film 15 when the surface roughness of the contact surface 113 of the spacer 11 was changed were measured. .

As a measuring method, a Ti film having a film thickness of 1 μm is formed on the contact surface 113 of the spacer 11 having a different surface roughness.
The N film is coated, the flatness of the film is measured, and the T
A cellophane tape was attached to the iN film, and the degree of adhesion was measured depending on whether the film peeled off when the iN film was pulled.

In this experiment, a film that did not peel off and had a flatness of 3 μm or less was regarded as excellent.

The surface roughness of the contact surface 113 and the result thereof are as shown in Table 2.

[0045]

[Table 2]

As can be seen from Table 2, the sample No. In 1,
Although the flatness could be set to 3 μm or less because of the thin film thickness of the covered TiN film, the TiN film was easily peeled off because the surface roughness was less than 0.1 μm in the center line average roughness (Ra). It was

The sample No. In No. 6, the surface roughness is as large as 3.0 μm in terms of center line average roughness (Ra).
Although the film was not peeled off, the flatness could not be set to 3 μm or less because the surface roughness of the contact surface 113 was too rough.

On the other hand, the sample No. Two
In No. 5, the surface roughness is the center line average roughness (Ra) of 0.1 to 2.
Since it is in the range of 0 μm, film peeling does not occur,
Further, the flatness could be set to 3 μm or less, and the standard could be satisfied.

(Experiment 2) Next, the conductive ceramic film 15
The spacers 11 of FIG. 1 having different thicknesses were prepared, and the flatness of the spacers 11 and the degree of close contact with the conductive ceramic film 15 were measured.

As in the case of Experimental Example 1, a TiN film was coated on the contact surface 113 of the spacer 11 as the conductive ceramic film 15 to assume its flatness, and a cellophane tape was attached to the TiN film. Then, the presence or absence of film peeling when pulled was checked. However, the contact surface 113
The surface roughness of the center line average roughness (Ra) is 0.2 μm,
The flatness was 1 μm.

In this experiment, a film having no flatness and having a flatness of 3 μm or less was regarded as excellent.

The film thickness of the conductive ceramic film 15 and the result thereof are as shown in Table 3.

[0053]

[Table 3]

As can be seen from Table 3, in the sample A, since the film thickness is as thin as 0.05 μm, the flatness of the spacer 11 can be set to 3 μm or less, but sufficient adhesion strength cannot be obtained, and it is easy to obtain. Peeling of the TiN film occurred.

Further, in the sample G, the film thickness was as thick as 4.0 μm, so that the flatness was 3.6 μm and 3 μm.
It could not be reduced to less than μm.

On the other hand, the sample No. B ~
Since F has a film thickness of 0.1 to 3.0 μm, peeling of the film does not occur, and the flatness of the holding member is 3.0.
It could be suppressed to less than μm.

(Experiment 3) Further, the conductivity was measured when the width L of the C surface formed on the edge portion 114 of the spacer 11 was changed.

The surface roughness of the contact surface 113 is 0.2 μm in terms of center line average roughness (Ra).
5, a TiN film is formed on the entire surface of the spacer 11 with a thickness of 1.0 μm.
coated as m. Then, from the contact surface 113 to the inner peripheral surface 1
Conductivity up to 16 was confirmed.

The respective results are shown in Table 4.

[0060]

[Table 4]

As can be seen from Table 4, the width L of the C surface is 0.0
If the thickness is 3 mm or less, even if the C-plane processing is performed on the edge portion 114, the edge is the same as the sharp edge.
Continuity was obtained from mm. From this, it is understood that the width L of the C surface formed on the inner and outer edge portions 114 of the holding member should be 0.04 mm or more.

In this experiment, an example in which the C surface is formed on the edge portion 114 of the spacer 11 is shown, but the same result is obtained even if the surface is a tapered surface or a curved surface.

[0063]

As described above, according to the present invention, among the holding members such as shims, clamps and spacers made of ceramics or glass, the width of 0.04 to 0.5 μm is provided at the inner and outer edge portions of the holding members. By providing a taper surface or a curved surface and coating at least the contact surface with the magnetic disk and the inner peripheral surface with a conductive ceramic film having a thickness of 0.1 to 3 μm, the static electricity charged on the magnetic disk can be efficiently released. In addition, the contact surface is hardly worn. Moreover, in the present invention, as the conductive ceramic film, TiC, TiN, ZrN, HfC, Ta is used.
C, ZrC, WC, VC, NbC, TiB ₂ , In ₂ O
_{Since one of the three} is coated, the coefficient of thermal expansion of the holding member and the magnetic disk can be equal to or approximate to that of the holding member, so that the film is not peeled off by the heat accompanying the high speed rotation. Since the magnetic disk is not distorted, the magnetic disk can be held with extremely high flatness accuracy.

Further, according to the present invention, the hub made of a conductive material is fixed to the rotating shaft, and the ring body is made of ceramics or glass.
A taper surface or a curved surface of 0.5 μm, and a film thickness of 0.1 at least on the contact surface with the magnetic disk and the inner peripheral surface.
The magnetic head floats above the magnetic disk by constructing the magnetic disk device by holding one or more magnetic disks made of ceramics or glass via a holding member formed by coating a conductive ceramic film of 3 .mu.m. The amount can be made extremely small, high-density recording (large capacity) can be realized, and the static electricity charged on the magnetic disk can be efficiently dissipated via the holding member and hub, preventing the recorded contents from being destroyed. can do.

[Brief description of drawings]

1A and 1B are views showing a spacer which is an example of a holding member according to the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a sectional view.

2A and 2B are diagrams showing a shim which is an example of a holding member according to the present invention, in which FIG. 2A is a perspective view and FIG. 2B is a sectional view.

3A and 3B are views showing a clamp which is an example of a holding member according to the present invention, in which FIG. 3A is a perspective view and FIG. 3B is a sectional view.

FIG. 4 is an enlarged view showing a main part of FIG.

FIG. 5 is a vertical cross-sectional view showing a magnetic disk device according to the present invention.

[Explanation of symbols]

 11: Spacer 112: Ring body 113: Contact surface 114: Edge part 115: Conductive ceramic film 116: Inner peripheral surface 10: Shim 12: Clamp 13: Rotating shaft 14: Hub 15: Magnetic disk 17: Magnetic head

Claims (3)

[Claims] 1. A holding member made of ring-shaped ceramics or glass for holding a magnetic disk at a predetermined position, the inner and outer edges of the holding member having a width of 0.
A magnetic disk holding member having a tapered surface or a curved surface of 04 to 0.5 mm and having at least a contact surface with a magnetic disk and an inner peripheral surface coated with a conductive ceramic film having a film thickness of 0.1 to 3 μm. 2. A hub made of a conductive material fixed to a rotating shaft, which is a ring body made of ceramics or glass, and has tapered surfaces or curved surfaces with a width of 0.04 to 0.5 mm at inner and outer edge portions. And a magnetic disk made of one or more ceramics or glass via a holding member having a conductive ceramic film having a thickness of 0.1 to 3 μm coated on at least the contact surface with the magnetic disk and the inner peripheral surface. A magnetic disk device that holds the. 3. The conductive ceramic film comprises TiC, Ti
N, HfC, ZrN, TaC, ZrC, WC, VC, N
The magnetic disk holding member according to claim 1 or the magnetic disk device according to claim 2, wherein the magnetic disk holding member is formed of one of bC, TiB ₂ , and In ₂ O ₃ .