JPH02124762A - Titania porcelain for magnetic head - Google Patents

Abstract

PURPOSE:To obtain the title porcelain which is difficult to cause the adsorptive phenomena even in a state nearly free from a pore and has durability by constituting this porcelain of the specified composition ratio of TiO2-Ba2Ti9O20.2MgTi2 O5-MgTi2O5 and forming the MgTi2O5 phase as a recessing part. CONSTITUTION:Titania porcelain improved in the surface is obtained by constituting the structure of three phases of TiO2-Ba2Ti9O20.2MgTi2O5-MgTi2O5 and regulating the composition ratio to a range having 5-40wt.% MgTi2O5 phase, 50-80wt.% Ba2Ti9O20. 2MgTi2O5 phase and 15-40wt.% TiO2 phase and forming the MgTi2O5 phase among three phases as a recessing part. The cutting degrees by a grinding and lapping of ceramic are made larger as the hardness of the surface is made smaller. When ceramic is constituted of such a structure that a plurality of mineral phases exist and these mineral phases have difference in hardness with each other and also a small amount of the phase low in hardness exists, the surface of a slider wherein a fine recessing part exists at a small amount can be produced by performing grinding and lap finishing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to titania porcelain that can be used as a magnetic head slider or spacer for storage devices, particularly floppy disk devices, and also as a tape guide for various tape devices.

Conventional Technology TiO2 phase and Ba2T1sO□ have been used as sliders for floppy disk devices. Barium titanate-based porcelain, which has a main mineral phase, is commonly used, and Zr
There are also reports of adding O2 or Al203. for example,
Japanese Patent Publication No. 62-24386, Japanese Patent Publication No. 6022645
5, Japanese Patent Publication No. 60-29669, etc.

The proposals described in these publications are based on TlO□ and Ba
By changing the blending ratio of the 2T1g02o phase and adding other components, we are able to control the coefficient of thermal expansion with the magnetic material, reduce porosity, control particle size, and improve mechanical strength. .

However, as floppy disk devices have become more sophisticated, the quality requirements for floppy disk slider materials have also become more sophisticated. 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 conventional slider materials lacked consideration of this requirement.

A slider for a floppy disk device makes surface contact with the disk, and at that interface there are moisture in the air, carbon dioxide gas, corrosive gas, powder friction, and lubricant on the disk surface. A manufacturing bore is present in the surface of the slider material. It is difficult to manufacture non-bore wood at low cost. The existence of a bore allows abrasive grains and grinding dust during grinding and lapping, fineness in the air, magnetic powder from the disk, etc. to enter, damaging the media and affecting the durability of the disk. On the other hand, if you reduce the bore,
Moisture is the main cause, causing adsorption phenomena, etc., and contact torque is generated between the slider material and the disk, which can cause failure of the disk device. It is conceivable to curve the slider surface with tape wrapping or the like in order to prevent the adsorption phenomenon, but it is difficult to control the processed shape and there are problems with reliability.

Problems to be Solved by the Invention The present invention takes into account the thermal expansion coefficient, processing characteristics, bore quality, etc., and provides a slider material that is resistant to adsorption phenomena even when there is almost no bore and is durable. It's about doing.

Means to solve the problemIn order to prevent adsorption phenomena etc. in a state where there is almost no bore,
A means of uniformly dispersing the mineral phase structure of the ceramic, which would produce uniform shallow flat depressions by flat finishing the slider material, was considered, and the present invention has realized this.

The titania porcelain of the present invention has a composition of 5 to 40 wt% MgTi205 phase, Ba2T1gO□ol2MgT
The i2O5 phase (the definition of this phase will be explained later) is 20
-3Qwt%, and Tin□ is 15-40wt%.

The degree of abrasion caused by grinding and lapping ceramics increases when the surface hardness is low. If the structure is made of ceramic with multiple mineral phases, where there is a difference in hardness between the mineral phases, and a small amount of a phase with lower hardness is present, then grinding and lapping can be performed to create a small amount of microscopic depressions. You can create a slider surface that looks like this. These recesses have a shallow and uniform depth, and unlike a bore, they do not retain dust or grinding powder easily, and the surface can be easily cleaned after finishing. The MgT120s phase forms these minute recesses, and the
The particles have a particle size of 15 μm and are dispersed in the mineral phase. The presence of these minute recesses reduces the actual contact area and prevents adsorption reduction due to moisture in the air, improves friction with the disk, improves compatibility with the media, and improves the slider material. Improves durability.

If the MgTi2O5 phase is less than 5 wt%, the effect of preventing moisture adsorption and the effect of improving the frictional state with the disk will be reduced. When the amount of MgTi, O, phase exceeds 40 wt%, wear resistance decreases and durability is affected.

Ba2T19020 ・2MgT120s phase is 2Qwt
If it is less than %, it is not preferable because it causes distortion when bonded with the thermal expansion coefficient (for example, Ni-2n ferrite).
The amount of the lsOzo.2MgTi2O5 phase is required to be 20% or more.

If the TiO□ phase is less than 5wt%, wear resistance decreases,
If the amount exceeds 40 wt%, the workability decreases, so as a magnetic head slider material, the TiO□ phase should be 15-40%.
wt% is appropriate.

Wipe the final sintered body of the example and add Ba2T1gO□o ・2MgT
12 [Weigh the raw materials BaC0, MgCO3 and TlO2 powder so that the 15 phase, TlO2 phase and MgTi2O5 phase have a predetermined weight ratio, add water and wet mix in a cylinder. This is calcined, water etc. are added again, and wet mixing is performed in a cylinder. After sieving, a binder such as polyvinyl alcohol is added and granulated. 1 ton/c [
Press molding is performed at a temperature of 11 or higher, and after firing in the atmosphere, a firing treatment is performed for densification. This fired product is ground and lapped to produce a predetermined slider material.

In addition, trace amounts of CaO1 mixed in from raw materials, cylinders, etc.
SrO1A1203, Sin, 2r02, etc. have no influence on the effects of the present invention.

Table 1 shows the starting composition of the porcelain thus obtained and the composition of the mineral phase produced by firing, and Table 2 shows its properties.

The first electron micrograph (36M photograph) of the composition of Nα1
This is shown in Figure A and Figure 1B. It can be seen that the phase that appears black in Figure 18 is the MgTi2O5 phase, and the boundary between the mineral phases is white and blurred, forming a recess. According to the reflection electron microscope, it is certain that the MgTi205 phase is depressed in the clear layer. It looks black in Figure 1B! , (gTi
. It is observed that the 05 phase is uniformly dispersed.

FIG. 2 shows a powder X-ray diffraction chart. The radiation source is CuK
Alpha rays were used and a Ni filter was used. The applied voltage is 4
At 0 kV, the applied current is 20 mA. The horizontal axis is the diffraction angle 2θ
(d, eg), the vertical axis is the chi-ray intensity, 1000 cp
s is the full scale. Three mineral phases are detected from Figure 2. Ba2T1gO2o・2MgTl. The Os phase is not listed in the ASTM card used when searching for powder X-ray data. When using an energy dispersive X-ray analyzer (EMAX Type 3000) manufactured by Horiba, the chemical composition is Ba2Tls02o 2MgTi
It is presumed to be a solid solution phase that can be expressed as 2O5, and throughout this specification this will be referred to as Ba2TlsO□ol 2MgT+
2[expressed as 15 phases.

Sintered bodies of various compositions were used for each test.

To measure the friction coefficient, as shown in Fig. 3, the tape 2 is brought into contact with the fixed pin 1 at an angle of 90°, a load TI is applied to one side of the tape 3, and a load change converter 4 is attached to the other side. The tape was moved back and forth, and the load T and g at the time of lifting were measured using a load change converter, and the coefficient of dynamic friction μk was calculated from the formula below.

μk = 2/ rr · fln (T2/T+) 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. A weight of 25 g was attached to T1, and a 6.3 mm wide chrome polishing tape was used, and the tape was reciprocated at a speed of 20 m/sec. The dynamic friction coefficient μ was calculated from the load T2 at the time of pulling up the tape after 100 reciprocations.

Workability was determined by fixing each sample to a jig, cutting it using a diamond grindstone, measuring the number of chips and chipping diameter using an optical microscope, and taking into account the required quality of the magnetic head material.

The results of each test are shown in Table 2. Sample Nos. 1 to 4 are test results of titania porcelain samples of the present invention, and Sample Nos. 5 to 10 are test results of porcelain samples that do not belong to the present invention. MgTi
By increasing the 2O5 phase, the coefficient of dynamic friction can be lowered and the frictional state during head running can be improved. However, sample No. 7, which does not belong to the present invention, has a sintered defective portion. In N028, the coefficient of dynamic friction increases, which affects the running of the slider. Also, No, 5.6
．． In 9.10, the number of chips during cutting increased,
The chipping diameter becomes larger, which affects workability.
Does not meet quality requirements for slider material for magnetic heads.

The effect structure of the invention is TlO2Ba2Tl, 0□o' 2MgTl2
It consists of three phases of O3MgTi205, and MgTi2O
5-40 wt% of 5 phases, Ba2TlsO2o 2Mg
Tl□Os phase is 20-80wt%, TlO2 phase is 15-80wt%
Titania for magnetic heads that satisfies the required quality of processing characteristics as a slider material for magnetic heads and improves the friction state of the slider by forming the MgTi20s phase of the three phases as recesses. You can get porcelain.

[Brief explanation of drawings]

FIG. 1A and FIG. 1B are porcelain sample No. of the present invention.
Fig. 2 is an electron micrograph of 1, and Fig. 2 is a powder X-ray diffraction chart thereof. FIG. 3 is a schematic diagram of the apparatus used to measure the coefficient of friction. Figure 6 (Continued amendment writing method) % formula % 2. Name of the invention Titania porcelain for magnetic heads 3. Relationship with the person making the amendment case

Claims (1)

[Claims] The structure is TiO_2-Ba_2Ti_9O_2_0・2
It consists of three phases of MgTi_2O_5-MgTi_2O_5, and the MgTi_2O_5 phase is 5 to 40 wt%, Ba
_2Ti_9O_2_0・2MgTi_2O_5 phase is 2
Titania porcelain for a magnetic head whose surface is improved by forming the MgTi_2O_5 phase as a concave portion within the range of 0 to 80 wt% and the TiO_2 phase of 15 to 40 wt%.