JPH02180754A - Slider of magnetic head - Google Patents

Abstract

PURPOSE:To improve slidability, wear resistance and machinability by rendering a compsn. obtd. by dispersing fine particles of alumina or the carbide of groups IVa, Va or VIa element of the periodic table and a specified amt. of fine carbon particles in a stabilized zirconia phase as the principal phase. CONSTITUTION:Fine ZrO2 particles are mixed with powder of a stabilizer such as Y2O3, fine particles of alumina or the carbide of groups IVa, Va or VIa element of the periodic table such as TiC, >=0.7wt.% fine carbon particles and a small amt. of a binder and the mixture is granulated. The resulting granules are molded and hot pressed to produce zirconia ceramics contg. fine particles of alumina or the carbide of the groups IVa, Va or VIa element and >=0.7wt.% fine carbon particles dispersed in a stabilized zirconia phase as the principal phase. The slider of a magnetic head is produced by machining the ceramics.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a slider used in a magnetic head used in data processing technology, particularly in the field of magnetic disk files, and particularly relates to a slider used in a magnetic head used in the field of magnetic disk files. The present invention relates to a slider for a magnetic head that is excellent and has been improved to reduce the amount of frictional electrification.

[Prior Art] As a magnetic head used in a magnetic disk, a floating head as shown in Japanese Patent Publication No. 57-569, for example, is often used. In such a floating head, a magnetic core made of a magnetic material with high magnetic permeability is fixed to the rear end of the slider. The magnetic core has a magnetic transducer gap on the lower surface side of the slider core, and an electromagnetic transducer winding is provided on the magnetic core to constitute a magnetic transducer.

A floating magnetic head having such a configuration lightly contacts the magnetic disk due to the force of a spring when the magnetic disk is stationary. Furthermore, when the magnetic disk is rotating, the air near the surface of the magnetic disk similarly moves, exerting a force that lifts the lower surface of the slider. Therefore, the magnetic head floats away from the magnetic disk while the magnetic disk is rotating.

On the other hand, when starting and stopping the rotation of the magnetic disk, the magnetic head slides on the magnetic disk. To explain the contact situation when stopping the rotation of a magnetic disk, as the rotation of the magnetic disk slows down, the flow of air on its surface gradually slows down. Then, when the buoyancy of the magnetic head is lost, the magnetic head collides with the surface of the magnetic disk, and due to the reaction, it flies up and falls back onto the disk surface. After repeating this motion several times, the magnetic head is dragged along the magnetic disk and then stops.

The magnetic head must withstand such shocks when starting and stopping, and its performance is determined by C8S characteristics (Contact-3T).
It is sometimes called "art-Stop".

In order to improve C5S performance, it is important to improve the sliding properties of the slider of the magnetic head. Furthermore, it is necessary that the surface of the slider be flat and free of pores, and that it has good wear resistance.

Further, as described above, the magnetic head is triboelectrically charged when it comes into contact with and slides on the magnetic disk. If this amount of Wf becomes excessively large, there is a risk that noise will occur in the signal winding of the magnetic transducer or that the flying height of the magnetic head will change. Therefore, it is desirable to construct the slider of the magnetic head using a material that causes as little frictional electrification as possible.

Furthermore, the slider of the magnetic head is, for example, disclosed in Japanese Patent Application Laid-open No. 55-1.
As shown in No. 63665, magnetic heads generally have extremely complex structures, but in order to manufacture magnetic heads with such complex structures with high productivity, the slider components must have excellent machinability. It is necessary. In other words, it is required that the cutting resistance during machining be low and that the cutting blade etc. be free from clogging. Further, during machining, crystal grains fall off from the machined portion, but it is desirable that this fallen portion be as small as possible.To this end, it is desirable that the crystal grains of the material constituting the slider be small.

To summarize the above-mentioned matters, the constituent materials of the slider of a magnetic head generally have: 1) excellent sliding properties; 2) excellent wear resistance; and 2) resistance to frictional charging.

■ Good machinability, ■ Small crystal grains, is requested.

As a method proposed to satisfy such required characteristics, there is a method disclosed in Japanese Patent Application Laid-Open No. 163665/1983. The slider in the same publication.

It is made of a mixture of Al2O2 and TfC,
The weight ratio of Al 203 and TiC(7) is 60:40
to 80:20. In the same issue, A! ;
It is stated that L20a-TiC ceramics has good workability, does not cause cracks or chipping when processed into complex shapes, and has excellent wear resistance.

[Problems to be Solved by the Invention] However, the slider made of Al 20 a and TiC does not have the C5S property, which is an important performance of the slider.
In particular, the sliding properties are poor. Furthermore, since Al 203 has high electrical insulating properties, in order to reduce electrical resistance and chargeability, it is necessary to contain a large amount of electrically conductive TiC, as stated in the same publication.

However, since TiC has high hardness, increasing the TiC content deteriorates the sliding properties.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention uses a stabilized zirconia phase as a main phase, and has a structure of IVa in the periodic table.

Fine particles of at least one compound selected from the group consisting of Va, carbides of group VIa elements, and alumina and fine carbon particles are dispersed in the main phase, and the content of fine carbon particles is 0. It is characterized by being 7% by weight or more.

The configuration of the present invention will be explained in detail below.

The slider of the magnetic head of the present invention has zirconia (zirconium oxide) as its main phase.

A stabilized zirconia phase is used as the zirconia phase. The stabilized zirconia phase has excellent sliding properties and is therefore suitable as a slider material for magnetic heads.

To stabilize the zirconia phase, Y203, MgO,
Add a stabilizer such as CaO. Zirconia without these stabilizers is cubic (C-phase) at high temperatures (above 2400°C), but when the temperature is lowered from 2400°C to about 1
In the range of 200°C, it becomes a tetragonal crystal (-phase), and at room temperature (approximately 1200°C or less) it becomes a monoclinic crystal (m-phase).

Also, when the amount of stabilizer is extremely small, zirconia becomes m-phase at room temperature, but when the amount of stabilizer is increased, zirconia becomes t-phase.
- phase will exist at room temperature, and if the amount of stabilizer is further increased, the C- phase will exist even at room temperature.

Therefore, in the slider of the magnetic head of the present invention, the zirconia phase contains a stabilizer sufficient to exist as cubic zirconia even at room temperature. In the case of Y2O5, the zirconia phase contains 5 to 20 mo%, and the remainder is substantially Z! ” 02 is desirable, but there is no problem even if MgO and CaO are also contained at the same time.

When such a stabilizer is included in excess, Z r O2 such as Y4Zr30I2 is contained in cubic zirconia.
A compound of Y203 precipitates, leading to deterioration of sliding properties and a decrease in strength. Therefore, 20 m o 1% or more Y2O3
It is undesirable to contain.

As mentioned above, when the amount of stabilizer decreases, 1-phase and m
- phase is also formed, but if m- phase is formed at room temperature, m- phase is generated due to heating and cooling to several hundred degrees Celsius during coating and patterning on the slider, which is accompanied by volume expansion. A phase arises;
There is a risk that slider warpage or pattern deviation may occur. Therefore, the lower limit of the stabilizer to produce stabilized zirconia is preferably about 5 moi% or more and as small as possible, and a more suitable amount is about 5 to about 10 moiL%.

In the slider of the present invention, the crystal grain size of the main phase of stabilized zirconia is preferably 12 pm or less, more preferably 10 pm or less. The crystal grain size of cubic zirconia is normally 15 gm, but by reducing it to 12 pm or less, machinability can be improved and the size of chipping can be reduced.

By dispersing fine particles of a specific type of carbide or alumina (aluminum oxide) in the zirconia main phase, the growth of the crystal grains of the zirconia phase can be suppressed and the crystal grains of the zirconia phase can be made finer.

That is, in the present invention, the periodic table IVa, Va, Vl
Fine particles of at least one compound (carbide or oxide) selected from the group consisting of carbide and alumina of element a are contained in a dispersed state in the zirconia main phase.

Carbides of elements of the periodic table rVa, Va, Via, Tic, ZrC, HfC, VC, NbC1TaC, W
Among them, Tic is preferable.

The above carbide may be used alone or in combination of two or more, or only alumina may be used instead of the carbide, or alumina and one or two of the above carbides.
You may use more than one species in combination.

S i O2, Fe to the extent normally allowed as impurities
2O3 can be contained, but the amount of Fe2e3 is 0
．． It is desirable that the content be 1 wt% or less.

There is no problem with the amount of SiO2 up to 5 wt%.

S i 02 is generally considered to be solidly dissolved in the zirconia phase. Y203, Cab, MgO, etc. may partially precipitate into monodispersed particles, or they may be dispersed in the zirconia phase as fine particles that combine with or react with added TiC, A I203, etc., but this is rarely the case. Not a problem.

As mentioned above, alumina and the carbides are dispersed in the zirconia phase and prevent the crystal grains from becoming coarse, but at the same time, because of their high hardness, when cutting zirconia ceramics, these particles become drenched. Acts as a shingle to prevent clogging of diamond cutting blades and improve cutting performance. Moreover, since it has high hardness, it increases the wear resistance of the slider.

The amounts of the carbide fine particles and alumina fine particles added are 0.5 to 30 vol% of the carbide fine particles, 0.5 to 30 voJ1% of the alumina fine particles, particularly 1 to 10 voJ1% of the carbide fine particles, and 1 to 10 vol% of the alumina fine particles.
% is preferred.

If the amount added is less than 0.5 vou%, the effect of refining crystal grains or improving machinability is small, and if it exceeds 30 voi%, the flatness of the slider surface will be deteriorated. Sliding properties deteriorate.

Regarding the particle size of carbide fine particles and alumina fine particles, if the average particle size exceeds 0.1 pm, the flatness of the slider surface will deteriorate, so for both, the average particle size should be 0, 'lILm or less, especially an average particle size of 0.05 gm or less. Preferably.

The slider of the magnetic head of the present invention contains fine carbon particles in addition to the zirconia main phase, carbide and/or alumina fine particles.

As the carbon fine particles, acetylene black, pyrolytic graphite, crushed graphite, etc. can be used regardless of the production history. These carbon particles have the effect of reducing the electrical resistance of the slider, reducing its charging properties, and increasing its sliding properties. Especially good.

The content of carbon fine particles is set to 0.7 vofL% or more in order to sufficiently reduce chargeability. Further, if the content of carbon fine particles exceeds 5 voJL%, the strength and abrasion resistance of the slider or the adhesion of the thin film will be reduced, so it is preferable that the content of carbon fine particles is 5voJ1% or less. Particularly preferred is 1 to 3 vo sentence %.

Furthermore, it is desirable that the relative density (compared to the theoretical density) of the slider used in the magnetic head of the present invention is 99 Talos or more. By achieving such a high density and reducing the bore, sliding properties can be improved. It will be excellent.

According to research conducted by the present inventors, it has been found that when carbon fine particles are dispersed in the zirconia main phase, the grain growth of zirconia crystal grains is suppressed and the grain size tends to become smaller. The machinability improves as the grain size decreases.

In order to produce the zirconia ceramics used in the present invention, Z r O2 fine particles, stabilizer powder such as Y2O3, carbides of elements IVa, Va, and VIa (for example, T
ic, ZrC, HfC, VClNbClTaC, WC)
Fine powder, AJL20:+ Fine powder and carbon fine powder are blended in a predetermined ratio, thoroughly mixed, dried, and granulated by adding a small amount of binder. This granulated powder is preformed into a molded body using a press machine having a cavity of the desired shape. This molded body is hot-pressed in a vacuum at a temperature of 1400 to 1600°C to obtain a zirconia ceramic as a sintered body.

The temperature at which this hot pressing is performed influences the performance of the obtained zirconia ceramics.

A temperature of 1400° C. or higher is necessary to make the relative density of phases other than carbon particles 99%. but.

If the temperature is 1600°C or higher, the crystal grains of stabilized zirconia will grow significantly, so it is desirable to hot press at 1600°C or lower.

The zirconia ceramic obtained by hot pressing is cut into the shape of a magnetic rad slider using a diamond blade, and then finished using a grinder or the like. A magnetic core, a signal coil, and an insulating film are attached to a slider-shaped object to form a magnetic head. As this insulating film, a film such as A-203, which is sputtered to a thickness of several tens of grams, is used.

In practicing the present invention, a magnetic core made of a thin film magnetic material can be used as a magnetic transducer, and an insulating thin film can be commonly deposited on both the magnetic core and a non-magnetic substrate, or a It can also be attached between a magnetic substrate and a magnetic core.

[Function] As mentioned above, the stabilized zirconia phase as the main phase has excellent sliding properties. Furthermore, the carbide fine particles and alumina fine particles dispersed in the zirconia main phase suppress the crystalline growth of the zirconia phase and make the crystal grains of the zirconia phase fine. It also improves wear resistance.

The carbon fine particles mainly reduce the specific resistance and the chargeability of the slider. It also further improves sliding properties. Furthermore, it is presumed that it can also have the effect of making the crystal grains of the zirconia phase finer.

Note that such refinement of crystal grains improves machinability and reduces the size of chipping.

[Example] Examples will be described below.

Example 1 78.0 parts by weight of ZrO2 powder with an average particle size of 0.034 m,
14.2 parts by weight of Y2O3 powder, 4.3 parts by weight of TiC powder, and 3.5 parts by weight of Al 203 powder (total of 10 parts by weight)
0 parts by weight), carbon fine powder with an average primary particle size of 200 angstroms was blended (No. 2 to 5), and for comparison, carbon powder without added carbon was also blended (No. 1).
).

The blending amounts are shown in Table 1.

Table 1 Blend amount (parts by weight) Wood ZrO278.0 parts by weight Y 2 0 al 4 , 2
ttT i C4, 3tt A look 2 03 3, 5 //
Loo,.

(Note that the molar ratio of Z r O2 and Y2O3 in this mixture is 91:9.) Next, the above formulation was mixed for 24 hours with an alumina pole using pure water as a solvent. The mixed solution was dried, 10% PVA solution was added thereto, and the mixture was granulated using a Laikai machine, and then preformed into a 80φ x 6-7 molded body at a pressure of 1 ton/crn'.
Hot pressed under the condition of 0.00 K g/c GoX1 hr. Regarding this sintered body, specific resistance, density, workability,
The sliding properties were measured.

The specific resistance was measured using a 1 cm square test piece using the Para method, which is a type of four-terminal method. When the specific resistance was high, silver paste was applied to both sides to determine the insulation resistance.

The density of the sintered body was measured by the underwater displacement method, and the relative density was determined by dividing the theoretical density.

Machinability was evaluated by making grooves with a diamond blade on a mirror-polished specimen and comparing the size of chipping that occurred on the lapping surface and the edge of the cut surface.

In addition, the sliding properties were measured using a C3S test in which a sintered body was cut into the shape of an actual thin-film magnetic head, and the disk was brought into contact with a magnetic disk and the disk was rotated. , shown in FIG.

Table 2 “1: ZrO2, Y2O3, TiC, A text 203,
Parts by weight added to 100 parts by weight in total (same as in Table 1) Grass 3: O: Very good, O: Good, Δ/Φ: Moderate.

From the above test results, when the amount of carbon added exceeds 0.5 parts by weight, the specific resistance decreases rapidly, and when the amount added is about 0.7 parts by weight or more, a sufficiently low specific resistance of 10'Ω・0 m or less is shown. It is recognized that

It is observed that when the amount of carbon added exceeds 5 parts by weight, the relative density becomes less than 90%. It is also recognized that when the amount of carbon added is in the range of about 1 to 3 parts by weight, both processability and FM workability are extremely excellent.

Furthermore, almost no bores were observed when observing the bores on the mirror surface, and it was found that the substrate satisfies the condition of having no bores on the surface, which is a basic characteristic of the substrate. This is presumably due to the fact that the matrix is inherently good and is sintered under pressure.

Comparative Example I Z Four sintered specimens were manufactured in which the mixing ratio of Z ro2 and Y2O3 was changed and no carbon was added, and their specific resistances were measured. The results are shown in Table 3. The particle size of the raw materials, manufacturing method, testing method, etc. are the same as in Example 1.

Table 3 Book: No, 7.8.9 is Z ro2: Y203=94: 6 (%le ratio) N
o, 10 is ZrO2:Y2O3=97=3 (molar ratio).

From Table 3, it is recognized that the resistivity decreases as the blending ratio of Tic increases. However, as the TiC content increases, the sliding properties deteriorate.

Furthermore, it is recognized that when the TiC content is low, the specific resistance is large and the triboelectric charging property is also large.

[Effects] As described above, the slider of the magnetic head of the present invention has stabilized zirconia as the main phase, in which specific carbide and/or alumina fine particles and carbon fine particles are dispersed, and has good sliding properties. It has excellent technical advantages such as excellent wear resistance and machinability, small crystal grains, low specific resistance, and low triboelectrification.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing the measurement results in Examples, and Figure 1 shows the relationship between the amount of carbon added and the specific resistance.
Moreover, FIG. 2 shows the relationship between the amount of carbon added and the relative density. Figure 1

Claims (2)

[Claims] (1) The main phase is a stabilized zirconia phase, and the periodic table IVa,
Fine particles of at least one compound selected from the group consisting of Va, carbides of group VIa elements, and alumina and fine carbon particles are dispersed in the main phase, and the content of the fine carbon particles is 0. A slider for a magnetic head, characterized in that the content is 7% by weight or more. (2) A slider for a magnetic head according to claim 1, wherein the stabilized zirconia phase is mainly cubic.