JP2587692B2 - Titania porcelain for magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a magnetic head slider or a spacer of a storage device, particularly a floppy disk drive,
The present invention also relates to titania porcelain which can be used as a tape guide for various tape devices.

2. Description of the Related Art As a slider for a floppy disk drive, barium titanate-based magnetism having a TiO ₂ phase and a Ba ₂ Ti ₉ O ₂₀ phase as a main mineral phase has been generally used, and ZrO ₂ or Al ₂ O ₃ has been conventionally used. There are reports of addition. For example, there are JP-B-62-24386, JP-A-60-226455, and JP-B-60-29669. The proposals described in these publications are Ti
By changing the mixing ratio of O ₂ and Ba ₂ Ti ₉ O ₂₀ phase and adding other components, control of thermal expansion coefficient with magnetic material, decrease of porosity, control of particle size and improvement of mechanical strength And so on.

However, with the advancement of floppy disk devices, the required quality of the slider material for floppy disks has also become more sophisticated, and the compatibility with the disks under severer load conditions has been increasing, and less wear and durability have been increasingly achieved. It is becoming required. In order to satisfy both of these characteristics, it is necessary to pay attention to the microstructure of the surface of the slider material, but the conventional slider material lacks consideration for this requirement.

The slider for a floppy disk device comes into surface contact with the disk, and moisture, carbon dioxide gas, corrosive gas, dust, and lubricant on the disk surface are present at the interface. There are manufacturing pores on the surface of the slider material. It is difficult to manufacture non-pore materials at low cost. The presence of the pores causes abrasive grains and grinding powder during grinding and lapping, dust in the air, magnetic powder of the disc, and the like to enter, damaging the media and affecting the durability of the disc. On the other hand, when the number of pores is reduced, moisture is a main cause, causing an adsorption phenomenon and the like, and a contact torque is generated between the slider material and the disk, which causes a failure of the disk device. Although it is conceivable to perform curved surface processing on the slider surface with tape wrap or the like in order to prevent the adsorption phenomenon or the like, it is difficult to control the processed shape, and there is a problem in reliability.

Problem to be Solved by the Invention The present invention provides a durable slider material that does not easily cause an adsorption phenomenon and the like even in a state where there is almost no pore, in consideration of thermal expansion coefficient, processing characteristics, pore quality, etc. Is to do.

Means for solving the problem In a state where there are few pores, in order to prevent the adsorption phenomenon and the like, the slider material is uniformly finished by dispersing the mineral phase structure of the ceramic so as to produce a uniform shallow flat depression. Means are conceivable, and the present invention has realized this.

The titania porcelain of the present invention has a MgTi ₂ O ₅ phase of 5
4040 wt%, _{20 to} 80 wt% of Ba ₂ Ti ₉ O ₂₀ .2MgTi ₂ O ₅ phase (the definition of this phase will be described later), and 15 to 40 wt% of TiO ₂ .

The degree of shaving by grinding and lapping the ceramic increases as the surface hardness decreases. If the composition has multiple mineral phases in the ceramic and there is a difference between the hardness of the mineral phases and a small number of low hardness phases are present, grinding and lapping will result in a small number of minute recesses The surface of the slider can be produced. This concave portion has a shallow and uniform depth, unlike a pore, does not easily hold dust, grinding powder, and the like, and easily becomes a clean surface by washing after finishing.
It is the MgTi ₂ O ₅ phase that forms these minute recesses, 3 to 15 μm.
It has a particle size of m and is dispersed in the mineral phase. Due to the presence of these minute recesses, the true contact area is reduced, preventing a decrease in adsorption due to the moisture in the air, etc., improving the frictional state with the disc, improving the compatibility with the media, and improving the slider material. Improve durability.

When the content of the MgTi ₂ O ₅ phase is less than 5 wt%, the effect of preventing the adsorption of moisture and the effect of improving the frictional state with the disk are reduced.
When the content of the MgTi ₂ O ₅ phase is more than 40% by weight, abrasion resistance is reduced and durability is affected.

Ba is less than _{2 Ti 9 O 20 · 2MgTi 2} O 5 phase 20 wt%, the thermal expansion coefficient (e.g. Ni-Zn ferrite) and Ba _{2 Ti 9 O 20 · 2MgTi 2} O 5 phase not preferable for causing distortion at the junction of Must be at least 20 wt%.

Is less than TiO ₂ phase 15 wt%, and reduced abrasion resistance, to decrease the workability becomes greater than 40 wt%, as the magnetic head slider material TiO ₂ phase is suitably 15 to 40 wt%.

Example In the final sintered body, Ba ₂ Ti ₉ O ₂₀ · 2MgTi ₂ O ₅ phase, TiO ₂
BaC as the raw material so that the phase and the MgTi ₂ O ₅ phase have a predetermined weight ratio.
Weigh the O ₃ , MgCO ₃ and TiO ₂ powders, add water and wet mix in a cylinder. This is calcined, water and the like are again added, and the mixture is wet-mixed in a cylinder. After sieving, a binder such as polyvinyl alcohol is added and granulated. 1ton it
Press molding at / cm ² or more, baking in air, and then baking treatment due to lack of density. This fired product is ground and wrapped to produce a predetermined slider material.

In addition, trace amounts of CaO, S
rO, Al ₂ O ₃ , SiO ₂ , ZrO _{2 and the} like have no effect on the effects of the present invention.

The starting composition of the porcelain thus obtained and the composition of the mineral phase generated by firing are shown in Table 1, and the characteristics thereof are shown in Table 2. Electron micrograph (SEM photograph) of No. 1 composition
The figure is shown in FIG. 1B. The phase that looks black in Fig. 1A is MgTi ₂ O
_{In the five} phases, the boundary of the mineral phase is white and blurred, and it can be seen that recesses are formed. According to the reflection electron microscope, it can be confirmed that the MgTi ₂ O ₅ phase is concave more clearly. In FIG. 1B, it is confirmed that the MgTi ₂ O ₅ phase that looks black is uniformly dispersed.

FIG. 2 shows a powder X-ray diffraction chart. The source is CuK
Using an α ray, a Ni filter was used. Applied voltage is 40kv
And the applied current is 20 mA. The horizontal axis is the diffraction angle 2θ (deg),
The vertical axis is the X-ray intensity, and 1000 cps was set as the full scale. From FIG. 2, three mineral phases are detected. Ba ₂ Ti ₉ O ₂₀
・ 2MgTi ₂ O ₅ phase is AS used for powder X-ray data search
Not listed on TM card. Using an energy dispersive X-ray analyzer (EMAX Type 3000) manufactured by Horiba, Ltd., it is estimated that the chemical composition is a solid solution phase that can be represented by Ba ₂ Ti ₉ O ₂₀ · 2MgTi ₂ O _5. Through the specification this is Ba ₂ Ti ₉
Expressed as O ₂₀ · 2MgTi ₂ O ₅ phase.

 Each sintered body of each composition was used for each test.

To measure the coefficient of friction, as shown in FIG. 3, a tape 2 is brought into contact with the fixing pin 1 at an angle of 90 °, a load T ₁ is applied to _one of the tapes 3, a load change transducer 4 is attached to the other, and the tape is attached. Was reciprocated to measure a load T ₂ g at the time of lifting from the load change converter, and a dynamic friction coefficient μk was calculated from the following equation.

μk = 2 / π · ln (T ₂ / T ₁ ) The fixing pin was a cylinder with an outer diameter of 3.2 mm and a length of 8 mm, and each sample was processed under the same conditions. Mounting the weight of 25g to T _1, the tape using a chromium abrasive tape 6.3mm wide, 20 mm /
It was reciprocated at the speed of sec. Dynamic friction coefficient μk was calculated from the load T ₂ of the time pulling after the tape 100 back and forth.

The workability was determined by fixing each sample to a jig, performing cutting using a diamond grindstone, measuring the number of chippings and the chipping diameter with an optical microscope, and further considering the required quality of the magnetic head material.

Table 2 shows the test results. Sample Nos. 1 to 4 are test results of the titania porcelain sample of the present invention, and 5 to 10 are test results of porcelain samples not belonging to the present invention. By increasing the MgTi ₂ O ₅ phase, the dynamic friction coefficient can be reduced, and the friction state during head running is improved. However,
Sample No. 7, which does not belong to the present invention, has a poor sintering portion. In No. 8, the dynamic friction coefficient increases, which affects the slider's running. Further, in Nos. 5, 6, 9, and 10, the number of chippings at the time of cutting increases or the chipping diameter increases, which affects workability and does not satisfy the required quality as a slider material for a magnetic head.

Effect tissue invention consists of three phases of _{TiO 2 -Ba 2 Ti 9 O 20} · 2MgTi 2 O 5 -MgTi 2 O 5, and MgTi ₂ O ₅ phase _{5~40wt%, Ba 2 Ti 9 O} 20 · 2MgT
i ₂ O ₅ phase 20 to 80 wt%, TiO ₂ phase is 15 to 40 wt%, by forming the inner MgTi ₂ O ₅ phase of three-phase as the recess is the required quality of the slider member for a magnetic head It is possible to obtain a titania porcelain for a magnetic head which satisfies the processing characteristics and the like and improves the frictional state of the slider.

[Brief description of the drawings]

1A and 1B are drawings schematically showing electron micrographs of sample No. 1 of the porcelain of the present invention, and FIG. 2 is a powder X-ray diffraction chart thereof. FIG. 3 is a schematic view of an apparatus used for measuring a coefficient of friction.

Claims (1)

(57) [Claims] 1. A ₂ tissue _{TiO -Ba 2 Ti 9 O 20 ·} 2MgTi 2 O 5 -MgTi 2
Consists of three phases of O ₅ , and 5-40 wt% of MgTi ₂ O ₅ phase, Ba ₂ Ti
A magnetic head whose surface is improved by forming MgTi ₂ O ₅ phase of three phases as a concave portion in a range where ₉ O ₂₀ .2 MgTi ₂ O ₅ phase has _{20 to} 80 wt% and TiO ₂ phase has 15 to 40 wt%. For titania porcelain.