JP3287063B2 - Ceramic material for floating magnetic head and floating magnetic head using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic material for a floating magnetic head suitable for a small hard disk drive and a floating magnetic head using the same.

[0002]

2. Description of the Related Art In recent years, a floating type magnetic head levitation method used in a small hard disk drive is such that the floating type magnetic head stops on the magnetic recording medium as the magnetic recording medium stops and rotates, and a predetermined distance (from the magnetic recording medium). Hereafter, a contact start / stop (hereinafter referred to as CSS) method of floating with a flying height is adopted. In recent years, high-density recording of magnetic disk devices has been studied in particular by reducing the flying height, and various improvements and developments have been made to further reduce the flying height.

Conventional slider materials for floating magnetic heads have a surface hardness of 1800 to 160 nm from the surface.
2500 Al ₂ O ₃ -TiC based ceramic having a (kgf / mm ²⁾ was used. The surface of the floating magnetic head facing the magnetic recording medium (hereinafter referred to as ABS) is processed by wet wrap using diamond particles. In particular, in the current and future environments where the flying height is becoming smaller and the thin film medium surface is required to be flattened, the improvement of the CSS characteristics is more important.

Therefore, improvement of the slider ceramic material and surface properties has been considered. In terms of surface properties, it is effective to roughen the facing surface to some extent from the viewpoint of reducing the contact surface with the magnetic recording medium. For the head, a method of obtaining finely irregularities on the ABS surface by ion milling, or for a monoridge head in which the ABS is made of Mn-Zn ferrite, see JP-A-1-25.
No. 1308 discloses an application of a method in which minute irregularities are formed on the ABS surface by a reverse sputtering method. In addition, for a floating magnetic head such as a composite in which the ABS is made of non-magnetic ceramics, a method of obtaining fine irregularities on the surface using non-magnetic ceramics that have irregularities due to lapping has been developed and a patent application has been filed. (Japanese Patent Application No. 4-199380).

[0005]

However, the above-described conventional configuration has a problem that it is difficult to obtain a smooth surface required for forming a thin film element when using nonmagnetic ceramics. In the reverse sputtering method and the method using ion milling, the core is mainly a thin film of permalloy metal, which is a metal having a low bonding force, and ABS has a strong bonding force.
The physical etch rate differences arising because of the l ₂ O ₃ -TiC based ceramic, a process essential poor workability that completely mask the element in order to reduce the level difference of the core portion and the slider Was. Also, Al
There is a problem that it is difficult to make the surface of the ₂ O ₃ -TiC ceramics uneven by etching, and it takes an enormous amount of time.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. By reducing the contact area with a magnetic recording medium and maintaining a flexible contact state, the CSS characteristic is remarkably improved and workability is improved. An object of the present invention is to provide a ceramic material for a floating magnetic head which is excellent in productivity and suitable for mass production at low cost, and a floating magnetic head using the same.

[0007]

In order to solve the above-mentioned problems, a ceramic material for a floating magnetic head according to the first aspect of the present invention is provided at a depth of 160 nm from a surface due to a difference in chemical composition and structure. Surface hardness of 75
0-1000 oxide and the surface hardness 600 having a phase of (kgf / mm ²⁾ an oxide of a single phase that Yusuke, surface hardness 350 to 800 from the surface in hardness at 160nm of depth (kgf / mm ²⁾ 3. The floating magnetic head according to claim 1, wherein the floating magnetic head has a two-layer structure constituted by laminating composite phases of oxides having a thickness of up to 1100 (kgf / mm ² ). A thin-film element is formed in the single-phase portion using a ceramic material for a die-type magnetic head, and a surface facing a magnetic recording medium is formed in the composite phase .

[0008]

According to this structure, it is possible to obtain a surface having a thin film element formed on a surface having a smooth surface property and having a property of reducing the area of a portion in contact with the magnetic recording medium. Further, since the contact portion with the magnetic recording medium is in the shape of a semicylindrical shape, flexible contact can be performed, and as a result, the flying height of the floating magnetic head can be reduced and the CSS characteristics can be improved.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a principal part of a ceramic material for a floating magnetic head of the present invention, and FIG. 2 is a schematic mirror view of the surface of the ceramic material for a floating magnetic head of the present invention. Reference numeral 1 denotes a substantially single-phase ceramic layer 2 having a surface hardness of 750 to 1000 (kgf / mm ² ) at a depth of 160 nm from the surface (hereinafter referred to as a single phase);
Surface hardness at a depth of 350 to 800 (kgf / m
m ² ) and a surface hardness of 600 to 1100 (kgf
/ Mm ² ), which is a ceramic material for a slider comprising two layers of a composite phase ceramic layer 3 (hereinafter, referred to as a composite layer) composed of a phase having a thickness of ² mm / mm ² .

The composition of the slider ceramic material 1 is 95, in terms of CaTiO ₃ and TiO ₂ in the single phase 2.
5 mol%, and in the composite phase 3, CaTiO ₃ , Sr
TiO ₃ , TiO ₂ , P ₂ O ₅ , SiO ₂ , ZrO ₂ ,
41,37,13.5,2,1 in terms of Al ₂ O ₃ composition.
5, 4, 1 mol%. Next, the surface hardness and area occupancy at a depth of 160 nm from the surface of each part in the schematic diagram of the ceramic material in FIG. 2 were measured. The results are shown in (Table 1).

[0011]

[Table 1]

The surface hardness was determined from the load at the maximum load of 1 gf and the insertion depth of the indenter using a dynamic hardness tester manufactured by Shimadzu Corporation. The depth is set to 160 nm in consideration of data accuracy. The surface area occupancy is the SE of the mirror surface
It was determined from M photographs.

As is clear from Table 1, the composite phase 3 of the ceramic material for slider 1 has a surface hardness of 160 to 800 (kgf / mm) at 160 nm from the surface occupying 4.3% of the surface area. ² ), an oxide phase having a hardness of 850 to 1000 (kgf / mm ² ), and an oxide phase having a hardness of 600 to 1100 (kgf / mm ² ). I understood that. The surface hardness of the single phase 2 is 750 to 1000 (kg
f / mm ² ).

The ceramic material 1 for the slider 1
Is to form a sintered body by molding two kinds of particles having the above-described composition into a two-layer structure using a dry molding method, firing at normal pressure in an oxygen atmosphere, and then performing HIP firing in an Ar atmosphere. And
Finishing was performed by wet lapping so that the thickness of the single phase 2 was about 100 μm. The surface property of the single phase 2 was 35 ° in terms of Ra, which was a peculiar smooth state without irregularities, and was the same as that of the conventional Al ₂ O ₃ —TiC ceramics.

Next, the floating magnetic head of the present invention will be described. FIG. 3 is a perspective view of a floating magnetic head using the ceramic material of the present invention. Reference numeral 4 denotes a slider comprising the single phase 2 and the composite phase 3; 5, an ABS portion which contacts the magnetic recording medium of the slider 4; 6, a leading portion; and 7, a protection comprising an alumina insulating layer applied to the surface of the single phase 2. Layer 8 is a thin film element.

The method of manufacturing the above-structured floating magnetic head will be described below.

First, a protective layer 7 of an alumina layer is formed on the surface of the single phase 2 of the slider ceramic material 1 by sputtering or the like.
Then, a thin film element 8 is formed using a thin film process. Next, after cutting into a predetermined size including the thin film element 8, an ABS part 5 is formed, and the surface of the ABS part 5 is mirror-finished by wet wrap using diamond particles having an average particle diameter of 0.12 μm. The floating magnetic head shown in FIG.

Next, the surface properties of the opposing surfaces were measured with respect to each head by using a stylus type surface roughness meter at a total of 10 points over a distance of 55 μm. Then assemble,
After examining the shape of the air bearing surface using a micro surface shape measuring device WYKO, CSS characteristics were measured using a 2.5-inch hard disk to evaluate the CSS characteristics of the magnetic head.

As a comparative example, a conventional Al ₂ O ₃ -T
A similar thin-film magnetic head was manufactured using the wet wrap for the iC-based ceramics in the thin-film process and the final processing of the ABS, and the same property / step / shape analysis and CSS characteristics were evaluated. FIG. 4 shows a measurement diagram of the surface properties. FIG.
FIG. 4A is a measurement diagram of the surface properties of the floating magnetic head of the present embodiment, and FIG. 4B is a measurement diagram of the surface characteristics of the floating magnetic head of the comparative example. Measurement results of surface properties are shown in Table 2.
It was shown to.

[0020]

[Table 2]

The surface properties were measured by taking the measured values into a personal computer and analyzing them. The stylus type surface roughness meter was measured using a stylus made of diamond and having a tip of 0.1 μm × 2.5 μm at a magnification of 1,000,000. The surface shape is measured approximately 45μ from the ridge line in the cross section direction of the air bearing surface in consideration of accuracy.
The measurement was performed under the condition of a magnification of 2.5 with respect to a portion excluding m (a total of about 90 μm in one air bearing surface). The configuration of the used 2.5-inch hard disk is shown below.

Substrate; Aluminum underlayer; Cr magnetic layer; Co-Ni sputtered film Surface layer; Carbon sputtered layer and fluorinated liquid lubricant layer applied to carbon layer surface Disk surface roughness; Ra {100} CSS test The disk drive conditions are as follows.

Head pressure: 55 mN (6.0 gf) Measuring position: 25 mm Required time to steady rotation speed: 4 seconds Steady rotation speed and time: 1 second at 2300 r / min Time required to stop from steady rotation speed: 4 Second rotation and stop time between rotations: 1 second As shown in FIGS. 4 (a) and 4 (b), there was a great difference between the heads in the properties of ABS. In the floating type magnetic head of this embodiment, a concave portion having a depth of several tens to 1000 ° exists, and the concave portion has a clear concave-convex shape. On the other hand, in the floating type magnetic head of the comparative example, although a part like a concave part having a depth of about 50 ° was slightly observed, it did not show the concave and convex shape. Further, in the floating magnetic head of this embodiment, 1.5 or more concave portions having a depth of 50 ° or more existed on the roughness curve on average. This number was almost zero in the floating magnetic head of the comparative example.

The recess is made of CaTiO ₃ , SrTiO.
₃ and its solid solution or TiO ₂ or trace amounts of P, S
The composition is different from that of the parent phase in which i, Zr, and Al are diffused.
It was an oxide phase of Ti, Ca, and Sr rich in Si, Zr, and Al.

FIG. 5 schematically shows the relationship between a roughness curve measured between a given surface A and a given surface B of the floating magnetic head of this embodiment using a contact type surface roughness meter, a phase structure and a particle state. FIG. In the figure, the upper figure shows the measured partial broken line A
FIG. 3B is a plan view showing the crystal phase of -B and the state of particles, and it is presumed that the recesses in the cross section are particles and particles of phase 1 having a chemically different soft hardness as described below. Is done. That is, the recesses are generated by the particles of phase 1 being more severely worn than the particles of the parent phase or phase 2 during processing, and the positions of the recesses are as shown in FIG. There is also a case of a particle or a group of particles containing, and a case of a grain boundary D between phases in FIG. The depth of the concave portion was measured as shown in FIG.

FIG. 6 is a schematic view showing the ABS surface shape of the floating type magnetic head in this embodiment. In the longitudinal direction showing the shape of the ABS of the ABS, the floating head has a semi-cylindrical shape. Also, the difference in elevation in the cross-sectional shape is 40 °.
It was a kamaboko having the above. The step between the core and the slider is 1 in the floating magnetic head of this embodiment.
80 ° was 5% in the floating magnetic head of the comparative example.
There was also $ 00. This is considered to be due to the fact that in the floating magnetic head of the comparative example, the hardness of the slider material was too high, and the wear rate of the slider portion was too low compared to the element portion in the lapping. FIG. 7 shows the friction coefficient μ.
3 shows the transition with respect to the number of CSSs. This is 1 rpm
FIG. 7 shows the transition of the average value μ of the dynamic friction coefficient μk between the disk m and the head with respect to the number of CSSs. As is apparent from FIG. 7, the floating magnetic head (Nos. 1, 2) of the present embodiment is shown.
The μ characteristics were superior between the floating magnetic heads (Nos. 3 and 4) and the comparative example. In the floating magnetic head of the comparative example, the value of μ was as large as about 0.8 when the number of times of CSS was 20000, and the disk state at that time did not reach the crash state as described above. The magnetic layer was confirmed over three turns. That is,
A having normal surface properties produced by lapping
In the thin film head to the ceramic l ₂ O ₃ -TiC system and ABS, ABS sectional shape greatly affects the CSS characteristics, in order to improve it was found that it is necessary semicylindrical shape. Further, it was also found that even with this improvement, the wear of the disk significantly progressed.

On the other hand, in the floating type magnetic head of this embodiment, the tendency of the increase of μ was very gentle, and the value of μ at 20,000 CSS times was as small as 0.4 or less. Further, even in the disk state at that time, the magnetic layer as described above could not be confirmed, and only a state where the lubricating layer was worn by sliding with the head was confirmed. That is, the ABS has a semicylindrical shape and a hardness of 350 to 800 (kgf / mm ² ) produced by the wrapping.
Oxide phase having a hardness of 600 to 1000 (kgf / mm
² ) The thin-film head using ABS as the surface-textured ceramic which is dented from the oxide phase having the above-mentioned hard magnetic disk has a higher μ characteristic than the above-described hard magnetic Al ₂ O ₃ —TiC-based floating magnetic head. It was also found that the CSS characteristics were remarkably improved in the wear characteristics.

Therefore, considering that the CSS characteristic is the wear characteristic of the disk caused by sliding between the magnetic head and the magnetic disk accompanied by delicate vibration of the head in any direction, the phase having the small hardness of the present invention is considered. Is a concave portion and has a depth of 50 ° or more. The concave portion has an irregular shape caused by an average of 1.5 or more in a roughness curve, and has a surface shape of 40 ° or more in a cross-sectional direction. It is clear that the head with a slider in the shape of a stub that has a difference in height has moderate hardness and a small contact area to soften the abrasion of the disk in sliding with the disk, does not hinder the head vibration, and improves the CSS characteristics. is there.

[0029]

As described above, according to the present invention, 160
Surface hardness 750-100 at hardness at depth of nm
0 (kgf / mm ² ) and a surface hardness of 350 at a depth of 160 nm from the surface.
Phase having a surface hardness of 600 to 1 (kgf / mm ² )
A ceramic material suitable for a slider material of a floating magnetic head composed of two layers of a composite phase ceramic material composed of a phase having 100 (kgf / mm ² ) can be realized. Since a floating magnetic head in which a thin film element is formed on the ceramic of the above and the part to be the ABS is mainly made of a composite phase ceramic material can be manufactured, the surface property of the ABS is changed from the surface to the surface.
Surface hardness of 350 to 800 (kgf / m) at a depth of 60 nm
m ² ) having a surface hardness of 600 to
A ceramic material in which a hard oxide having a hardness of 1100 (kgf / mm ² ) is uniformly dispersed between phases is formed into a concave and convex shape in which a soft phase becomes a concave portion. With a head processed to have a semi-cylindrical shape, it has an optimal hardness, a small contact area, and a small dynamic friction resistance. It has remarkably excellent CSS characteristics, high workability, high productivity and low cost, and excellent mass productivity. Thus, a floating magnetic head can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a ceramic material for a floating magnetic head according to the present invention.

FIG. 2 is a schematic diagram of a mirror surface of a ceramic material for a floating magnetic head according to the present invention.

FIG. 3 is a perspective view of a floating magnetic head using the ceramic material of the present invention.

FIG. 4A is a measurement diagram of the surface texture of the floating magnetic head of the present embodiment; FIG. 4B is a measurement diagram of the surface texture of the floating magnetic head of the comparative example;

FIG. 5 is a schematic diagram showing the surface shape, phase configuration, and particle state of the floating magnetic head of this embodiment measured using a contact surface roughness meter.

FIG. 6 is a schematic diagram showing an ABS surface shape of the floating magnetic head in the embodiment.

FIG. 7 is a transition diagram of the friction coefficient μ with respect to the number of CSSs.

[Explanation of symbols]

 Reference Signs List 1 ceramic material for slider 2 ceramic layer (single phase) 3 ceramic layer (composite phase) 4 slider 5 ABS part 6 leading part 7 protective layer 8 thin film element

Continuation of front page (56) References JP-A-6-44547 (JP, A) JP-A-5-166320 (JP, A) JP-A-6-139512 (JP, A) JP-A-6-124401 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/60 G11B 5/187 G11B 5/255 C04B 35/00

Claims (2)

(57) [Claims] A phase of claim 1] oxide of a single phase that have a surface hardness 750~1000 (kgf / mm ²⁾ from the surface of the chemical composition and structure is due to different in hardness at 160nm depth, from the surface Two layers formed by laminating a composite phase of an oxide having a surface hardness of 350 to 800 (kgf / mm ² ) and an oxide having a surface hardness of 600 to 1100 (kgf / mm ² ) at a depth of 160 nm. Ceramic material for floating magnetic head with structure. 2. A thin-film element is formed in the single-phase portion using the ceramic material for a floating magnetic head according to claim 1, and a surface facing a magnetic recording medium is formed in the composite phase. Floating type magnetic head.