JPH04372703A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the reliability of the operation of the magnetic disk device by suppressing the generation of worn powder, etc., in a head disk assembly. CONSTITUTION:Carbon protective films 15 consisting of an amorphous carbon, etc., are deposited and formed on floating rails 12 (floating surfaces) which are projectingly provided on a slider 11 constituting a magnetic head and faces a magnetic disk. Since the worn powder generated at the time of the contact between the head and the disk is the carbon, the powder is instantaneously burned by the friction heat in the contact section and is annihilated in the form of carbon dioxide.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique that is effective when applied to a magnetic disk drive comprising a magnetic recording medium and a magnetic head.

0002

[Background Art] An important issue in ensuring the reliability of magnetic disk devices is to prevent deterioration of the magnetic recording medium (magnetic disk) caused by head crashes, etc., and to maintain information recording and reproducing functions over a long period of time. The objective is to maintain the system smoothly throughout the period. Head crashes occur due to repeated contact between a magnetic disk and a magnetic head over a long period of time.

The main cause of contact between the magnetic disk and the magnetic head is hard and soft dust floating in the head disk assembly (HDA). These two types of dust enter the head/disk gap while the head is flying, impairing the stability of the head flying, and causing direct contact between the head and the disk. At this time, the head flying surface and the disk surface wear out, and the two types of wear particles mentioned above are transferred to the flying surface, which disturbs the normal air flow and reduces the head flying height, causing direct contact between the head and the disk. The frequency of contact increases, and the amount of abrasion powder adhering to the head air bearing surface increases, leading to media deterioration (head crash). Therefore, in order to prevent head crashes,
It is important not to generate wear particles that adhere to the head flying surface and the disk surface. Additionally, in order to prevent wear on the disk side and ensure the reliability of the information stored on the disk, it is necessary to make the hardness of the material that makes up the head lower than the hardness of the disk surface. .

The magnetic head material is magnetic ferrite (MnZ
n material) and composite ceramics (ZrO2) containing alumina (Al2O3) and titanium carbide (TiC) particles
materials) are usually used. On the other hand, there are roughly two types of magnetic disks that are combined with magnetic heads. One is a coating-type medium in which a magnetic material made by mixing conventional magnetic powder, binder, and reinforcing material (filler) is coated on a substrate, and the other is a thin-film magnetic recording medium in which a magnetic thin film is used. .

Thin film magnetic recording media have recently attracted attention as high recording density media, and their configurations are as follows, for example. The substrate consists of an aluminum alloy disk and a hard base layer formed thereon. An intermediate layer is formed on the substrate for the purpose of improving adhesion and improving the characteristics of the magnetic layer. A magnetic layer is formed on the intermediate layer. A protective layer (generally a carbon layer) and a lubricating layer are formed on the magnetic layer before actual use.

[0006] Considering the contact at the interface between the magnetic head and the magnetic disk, in coated media, the head material and filler mainly come into contact. At this time, both the head material and the filler are worn, and the degree of wear depends on the relative hardness of the head material and the filler. Then, the abrasion powder of the head material and filler adheres to the air bearing surface while the head is flying.

On the other hand, it is known that in thin film magnetic recording media, both the head material and the medium protective film are worn out, and the degree of wear depends on the relative hardness of the head material and the protective film material.

[0008] As a technique for preventing wear of the air bearing surface of a magnetic head, for example, a technique disclosed in Japanese Patent Laid-Open No. 1-285015 is known. In this technology, the part of the titanium carbide particles exposed on the levitation force generating surface of the levitation rail in the head is covered with silicon dioxide (SiO2), and a fluorine-based lubricant containing hydroxyl groups is firmly attached to the levitation surface. The purpose is to make it possible to stably maintain the sliding and floating state with respect to the magnetic disk.

[0009]

[Problems to be Solved by the Invention] The above-mentioned prior art has problems with wear of the silicon dioxide protective layer after the lubricant is scattered by the air flow that generates heat generated by contact between the head and the disk and the head flying force. This is not taken into consideration, and there is a concern that foreign matter generated by the wear of the silicon dioxide protective layer may re-adhere to the air bearing surface, which may cause the aforementioned head crash. On the other hand, in order to suppress media wear and ensure the reliability of recorded information, it is necessary to set the hardness of the head material to be relatively lower than the hardness of the media surface. This causes an increase in abrasion powder due to accelerated wear on the head side, and it is necessary to take measures to prevent the generated abrasion powder from re-adhering to the head or disk.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic disk drive in which the occurrence of abrasion particles and the like in a head disk assembly is suppressed and the reliability of operation is improved.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

0012

[Means for Solving the Problems] Among the inventions disclosed in this application, a brief overview of typical inventions will be as follows:
It is as follows.

That is, the magnetic disk device of the present invention has the following features:
In a magnetic disk device having a head disk assembly of a closed structure type, a carbon protective film made of, for example, amorphous carbon is formed on the air bearing surface of the magnetic head that constitutes the head disk assembly, which faces the magnetic disk. It is.

[0014]

[Operation] According to the magnetic disk device of the present invention described above,
The wear particles generated from the magnetic head when the magnetic head contacts the magnetic disk are composed of carbon with part of the carbon protective film peeled off, so the wear particles are instantly burned by the frictional heat generated at the contact area, and carbon dioxide is generated. Since it disappears as a gas, troubles such as head crashes caused by re-adhesion of worn particles to the head flying surface or the magnetic disk surface are reliably prevented, and the reliability of the operation of the magnetic disk device is improved.

In addition, when the hardness of the magnetic disk is set relatively larger than that of the magnetic head to prevent wear on the magnetic disk side, the wear of the carbon protective film on the magnetic head side becomes relatively large. Since the wear powder generated from the carbon protective film burns and disappears, the reduction of the wear powder in this setting becomes more effective.

Furthermore, for example, in the case of a thin film magnetic recording medium in which the magnetic disk has a protective film made of a carbon layer on its surface, the abrasion particles generated from both the magnetic head and the magnetic disk turn into carbon, and it is possible to reduce the abrasion particles. It becomes convenient.

The present inventors have developed a magnetic head that uses ZrO2-based ceramics and has a carbon protective film made of amorphous carbon formed on its air bearing surface, and a magnetic disk that is made of a thin-film magnetic recording medium that has a carbon protective film on its surface. Experiments to confirm the principle of the present invention were conducted using combinations as follows.

A head/disk floating contact experiment was conducted under the conditions of a head flying height of 0.03 μm, the same radial position on the disk surface, and a disk circumferential speed of 30 m/s. was worn down by 10 to 20 μm. However, no abrasion powder adhered to the surface of the magnetic disk, and no carbon was detected from the deposits on the air bearing surface of the head.

On the other hand, when a similar floating contact experiment was conducted in a nitrogen gas atmosphere with oxygen cut off, abrasion powder was observed to adhere to both the magnetic disk surface and the magnetic head air bearing surface.

In other words, carbon powder generated by contact between a magnetic head and a magnetic disk, on which a carbon protective film is formed on the air bearing surface, is burned by the frictional heat generated during contact between the head and the disk, and disappears as carbon dioxide gas. confirmed.

[0021] Raman analysis of the carbon protective film surface after a head/disk floating contact experiment in a nitrogen gas atmosphere revealed that
The contact temperature between the ZrO2 ceramics on the head side and the carbon protective film on the disk side is 400°C, and the contact temperature between the head and the filler of the coating type medium is T.
By analyzing the color change of iC particles to TiO2,
The estimated temperature was found to be 500-600°C. In either case, the temperature is sufficient to burn the carbon.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic disk drive which is an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an enlarged perspective view showing a magnetic head included in a head disk assembly constituting a magnetic disk device according to an embodiment of the present invention.

The magnetic head 10 of this embodiment has a plurality of floating rails 12 (
The slider 11 is made of, for example, a ZrO2-based ferrite material, and a recording/reproducing (R/W) element 13 is fixed to a part of the slider 11.

Each floating rail 12 has an inflow end tapered part 12a provided at the end on the side where an airflow generated by the rotation of a magnetic disk (not shown) arrives, and a flat part 1.
The recording/reproducing element 13 is arranged at the rear end of the flat part 12b on the opposite side of the inflow end tapered part 12a. Further, the recording/reproducing element 13 is covered with a protective film 14 made of, for example, alumina (AlO3).

In this case, the floating rail 1 of the slider 11
A carbon protective film 15 made of amorphous carbon formed by sputtering, for example, is formed on the area where the carbon protective film 2 protrudes after the formation of each of the above-mentioned constituent members. The thickness of this carbon protective film 15 is set, for example, in a range of 5 to 50 nm.

The magnetic head may have the shape shown in FIGS. 2 and 3 in addition to the shape described above.

That is, FIG. 2 shows another magnetic head 10A.
FIG. 3 is a perspective view showing the same, and FIG. 3 is a side view thereof.

In the case of the magnetic head 10A of FIG. 2,
The slider 11a is made of a magnetic ferrite material such as MnZn, and has a structure in which a center rail (air bearing surface) 16 is arranged between the floating rails 12. Further, at the rear end of the center rail 16, a recording/reproducing element 17 is arranged, which consists of a core 17a fixed to the slider 11a with one end forming a gap 17c, and a winding 17b wound around the core 17a. There is.

Furthermore, a carbon protective film 15 is formed on the surfaces of the floating rail 12 and the center rail 16.

On the other hand, FIG. 4 shows an example of the configuration of a magnetic disk 20 used in combination with the magnetic head 10 or 10A as described above.

[0032] The substrate 21 is made of an aluminum alloy,
A Ni--P base film is formed thereon as a base layer 22. A Cr film is formed as an intermediate layer 23 on the base layer 22 . Further, on the intermediate layer 23, a magnetic layer 2
4 as Co-Ni-Zr or Co-Cr-Ta
A magnetic film is formed. A protective layer 25 of, for example, i-carbon is formed on the magnetic layer 24, and a lubricating layer 26 is formed thereon.

This i-carbon is a diamond-like carbon thin film obtained by appropriately controlling the formation conditions, for example, by sputtering, and has a harder hardness than the amorphous carbon that constitutes the carbon protective film 15 of the magnetic head 10 and 10A. is much larger.

FIG. 5 shows amorphous carbon forming the carbon protective film 15 formed on the magnetic heads 10 and 10A, and i
- It is a diagram showing the fluorescent X-ray intensity ratio of carbon at heat treatment temperature.

The amorphous carbon constituting the carbon protective film 15 on the side of the magnetic heads 10 and 10A shows that the fluorescent X-ray intensity ratio decreases at temperatures above 200° C., indicating that it burns at temperatures above that temperature. magnetic disk 20
It is known that i-carbon forming the side protective layer 25 burns at 300°C or higher. That is, i-carbon is less combustible than amorphous carbon, and also has greater hardness as described above. Therefore, magnetic head 1
When the magnetic disk 20 comes into contact with the magnetic disk 20, the wear and damage on the magnetic disk 20 side will be slight.

An example of the operation of the magnetic disk device in this embodiment will be explained below.

FIG. 6 is an explanatory diagram showing an example of a head flying state in the magnetic disk device of this embodiment.

First, the magnetic head 10 (10A) receives a levitation force from the levitation rail 12 due to the air flow 31 generated by rotating the magnetic disk 20 at high speed in the rotational direction 30, and the magnetic head 10 (10A) receives a levitation force from the surface of the magnetic disk 20. Continue levitation while maintaining a certain gap. However, if floating dust 32 in the head disk assembly enters between the magnetic head 10 and the magnetic disk 20, contact occurs between the two.

At this time, conventionally, this contact causes the floating rail 12 to wear out, and the generated abrasion powder may re-adhere to the surface of the floating rail 12, causing a decrease in the flying height of the head.

On the other hand, in the case of this embodiment, the surface of the floating rail 12 of the magnetic head 10 (10A) is
Since it is covered with the carbon protective film 15, when the head/disk contacts, the abrasion powder generated from the carbon protective film 15 is instantaneously burned by the frictional heat generated at the contact area, and disappears as carbon dioxide gas. Therefore, there is no concern that wear particles will re-adhere to the flying rail 12 and cause a reduction in the flying height of the head, and head crashes that occur due to repeated contact between the magnetic head 10 and the magnetic disk 20 can be avoided. The operational reliability of the magnetic disk device is certainly improved.

In addition, the protective layer 25 on the side of the magnetic disk 20
The i-carbon constituting the magnetic head 10 (10A)
Since the hardness and combustion temperature are higher than that of the amorphous carbon that constitutes the carbon protective film 15 on the side, the damage on the side of the magnetic disk 20 is slight when the two come into contact.
The reliability of information recorded on the magnetic disk 20 can be ensured.

[0042] The invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the spirit thereof. Needless to say, it is.

For example, the configurations of the magnetic head and magnetic disk are not limited to those exemplified in the above-described embodiments.

[0044]

[Effects of the Invention] Among the inventions disclosed in this application, the effects obtained by the typical inventions are briefly explained as follows.
It is as follows.

That is, according to the magnetic disk device of the present invention, it is possible to suppress the generation of abrasion particles in the head disk assembly, thereby improving operational reliability.

[Brief explanation of drawings]

FIG. 1 is an enlarged perspective view showing a magnetic head of a head disk assembly constituting a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a modification of the magnetic head.

FIG. 3 is a side view thereof.

FIG. 4 is a schematic cross-sectional view showing the configuration of a magnetic disk in a magnetic disk device that is an embodiment of the present invention.

FIG. 5 is a diagram showing the fluorescent X-ray intensity ratio of amorphous carbon forming a carbon protective film formed on a magnetic head and i-carbon forming a protective layer of a magnetic disk at a heat treatment temperature.

FIG. 6 is an explanatory diagram showing an example of a head floating state in a magnetic disk device according to an embodiment of the present invention.

[Explanation of symbols]

10 Magnetic head 10A magnetic head 11 Slider 11a Slider 12 Floating rail (levitating surface) 12a　Inflow end taper part 12b Flat part 13 Recording/reproducing element 14 Protective film 15 Carbon protective film 16 Center rail (floating surface) 17 Recording/reproducing element 17a Core 17b Winding wire 17c Gap 20 Magnetic disk 21　Substrate 22 Base layer 23 Middle class 24 Magnetic layer 25 Protective layer 26 Lubricant layer 30 Rotation direction 31 Air flow 32 Floating dust

Claims (1)

[Claims] 1. A magnetic disk drive having a head disk assembly of a closed structure type, wherein a carbon protective film is formed on the air bearing surface of the magnetic head constituting the head disk assembly, which faces the magnetic disk. A magnetic disk device characterized by: