JPS6252172A - Ceramic composition for magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a magnetic head porcelain (hereinafter referred to as a porcelain head slider) that supports a magnetic pole piece (ferrite core) used in a magnetic head such as a floppy disk. The present invention relates to a porcelain composition, and more particularly to a porcelain composition for a slider for a porcelain head suitable for Mn-Zn 7 elite.

(Background Art) As shown in the figure, the slider 1 generally has a seven-effect core 2 bonded to it by heat treatment via an adhesive glass 3 to form a magnetic head. Therefore, if there is a large difference in thermal expansion between each of the slider and the ferrite core, the thermal history during heat treatment will cause cracks and residual strain in these materials, resulting in guff peeling and the like during the assembly process. Therefore, the porcelain composition and composition ratio of the slider must be selected to match the coefficient of thermal expansion of the ferrite core.

In addition, there are various grades of ferrite core depending on its use, and the coefficient of thermal expansion varies from 105 to 105 depending on the grade.
It needs to be applied over a wide range of 125×10/°C.

Therefore, it is desired that the coefficient of thermal expansion of the slider can be easily selected from a wide range of 105 to 125 x 10 /°C by changing its composition ratio.

Further, this slider is required to have as few bores as possible in its sintered porcelain body. If there are many bores on the surface of the sintered body that comes into contact with the floppy disk, the magnetic powder coated on the disk surface will not easily adhere to the inside of the bore, and the presence of the attached magnetic powder will cause problems during recording and playback. It also impairs the magnetic properties of

Furthermore, the porcelain of this slider must be sufficiently sintered and densified. If the porcelain is insufficiently sintered and its strength and toughness are poor, chipping and cracking will occur in the porcelain, leading to serious defects such as damage to the disk itself when it is run on a floppy disk.

On the other hand, Ni-Zn ferrite has traditionally been used as the core of magnetic heads, but currently Ni-Zn, Mn-Z
Since n7 eft has better magnetic properties, especially coercive force, it is being replaced by Mn-Zn ferrite.

(Description of Prior Art) Conventionally, a slider composition applied to Ni, -Zn ferrite has a thermal expansion coefficient of 90 to 98 x 10/
7-orsterite and barium titanate, which have a temperature almost the same as ℃, are known. However, when applying these porcelains to Mn-Zn ferrite, it is difficult to apply these porcelains because the coefficient of thermal expansion of Mn-Zn7 ferrite is 105 to 125X10/°C, and the difference in thermal expansion is too large.

On the other hand, Sphyta compositions applied to Mn-Zn ferrite have traditionally been based on titanate-based compounds, such as calcium titanate, magnesium titanate, and strontium titanate, which have a coefficient of thermal expansion almost the same as that of Mn-Zn ferrite. It is known that the degree of However, Mn-Zn ferrite is
There are a wide variety of grades in the wide range of 05 to 125 x 10 /℃, but conventionally the thermal expansion coefficient in this wide range can be changed linearly by simply changing the composition ratio, making it easy to create the thermal expansion coefficient of various grades. A slider composition for a magnetic head that matches the above has not been found.

On the other hand, in the case of a composition mainly composed of the titanate compound, when fired in argon gas, for example, T1 ions are reduced and the color tone of the porcelain changes drastically. In this case, a process is required to restore the changed color of the porcelain.

Furthermore, since the sintered body mainly composed of the titanate Ihe has a problem of detachment of crystal grains during mirror finishing, grain removal and selective polishing (soft grains are selectively polished) There is a desire for a composition for a magnetic herad slider that has excellent workability and is free of .

(Problems to be Solved by the Present Invention) In view of the above-mentioned current situation, the present inventor has conducted extensive research and found that Mn-Z
By adding a specific amount of TiO2 to the main component of the CaO-5lot compound, which has a thermal expansion coefficient close to that of nyefite, the 5102 component was converted into a calcium silicate (CaSi, Os) compound totitanium acidity/I other than the Gaffs phase. M
Thermal expansion coefficient of n-Zn 7 elite 105-125Xl
A slider composition for a magnetic head that can be applied to a wide range of o/℃, has good sinterability, reduces the occurrence of bores, prevents the occurrence of color unevenness due to reducing atmosphere treatment, and has excellent mirror finish properties. We found that it is possible to obtain

(Purpose of the invention) Therefore, the present invention provides calcium silicate (Ca).

51os) compound and flX”/acidity A/shi17 A
It is a dense sintered body with a small glass component consisting of (CaTi03) h'), and can be applied to a wide range of thermal expansion coefficients a of Mn-Zn ferrite, and has good sinterability and less occurrence of bores. Another object of the present invention is to provide a magnetic head sifter composition that can prevent the occurrence of color unevenness due to treatment in a reducing atmosphere and has an excellent mirror finish.

(Means for solving the problem) According to the present invention, 22 to 50 mol% of Si and Oz and Ti
O2 2-30-1 near 9% and OaO 45-47
There is provided a ceramic composition for a magnetic head comprising: %Mo/L'%.

A porcelain composition having the above composition range mainly consists of Ca5103 phase or Ca35izO phase at the proper firing temperature.
It has a fine uniform mixed structure consisting of one or more types of F phases and CaTiO3 phase, and is different from conventional Mgo − such as forsterite.
The sinterability of 810z-based porcelain also improves, and a dense sintered body can be obtained.

Furthermore, in a porcelain composition having the above composition range, C
a510s phase or Ca5SizOv phase and CaTiOs
)7fJ (7) Since the homogeneous mixed structure is the main component and the glass component is small, grain shedding and selective polishing during mirror finishing caused by the glass component present in the grain boundaries are reduced. In addition, due to the presence of Ca5l-03 phase, CaxSi, and 20y phase, the hardness is higher than that of conventional titanate-based slider materials.
- Zn is close to ferrite, making it easier to maintain the flatness of the head guarantee surface (the surface that contacts the floppy disk) after glass welding. Also, CaSi, 03 and CaTiOs
Since it has a stable crystal phase consisting of a uniform calcined product of A slider having a desired coefficient of thermal expansion can be obtained.

When 5iOz is less than 22 mol%, densification of the sintered body is inhibited on the side where the amount of CaO added is large, and densification of the sintered body is good on the side where TiO2lO2 is added, but the color tone changes due to reduction.
Color unevenness is more likely to occur. When 5lo2 exceeds 50 mol%, Si and Oz exist alone and a glass phase tends to be formed, resulting in the formation of bores and insufficient densification.

When Tl-0s is less than 2 mol%, CaSiO3 and Cas
Since the sintering of Si 20 t cannot be sufficiently promoted, the generation of bores cannot be sufficiently suppressed. When T1.02 exceeds 30 mol%, ca'
Since the formation of the rIQs phase increases, the effect under a reducing atmosphere becomes more pronounced, and color unevenness is more likely to occur.5lo2
Since CaTi and 5iOs phases (thermal expansion coefficient: 65×1o-7° C.) are formed on the side where the VIA addition is large, the thermal expansion coefficient becomes extremely low. 510 when CaO is less than 45 mol%
2 SiO on the side with more addition! The compactness of the sintered body is deteriorated, in which a glass phase mainly composed of decreases. Ca
If O exceeds 57 mol %, CaO tends to exist in an unreacted state, resulting in hydration and poor water resistance, making the slider generally unsuitable for use in magnetic heads.

The CaSi, 03 and Ca1Si, zOt phases have pure composition ratios (CaO:5102=50250 mol% and 60:
However, by adding TiO2, it is difficult to obtain a dense sintered body from 5iO3 and Ca3Si,
・Has an auxiliary effect on the formation of the 20y phase, and both phases are similar to the conventional T
Compared to the j-Ch -CaO system, the calcination temperature is relatively low, that is, the conventional calcination temperature of about 1,000 to 1,150°C has been reduced to about 90°C.
Crystal formation progresses at about 0 to 1100°C, uniform crystal growth occurs during main firing, and abnormal grain growth can be suppressed.

Hereinafter, the present invention will be explained in detail with reference to Examples.

In the method of manufacturing a magnetic head slider in the present invention, raw materials are weighed to a predetermined composition ratio, mixed and pulverized, and then calcined.The calcined product is then pulverized, an organic binder is added and granulated, and a predetermined composition ratio is obtained. The usual method of shaping and firing is used.

(Example) Commercially available industrial raw materials (purity 98% or higher) were used, including silica (Si, Ch) as a silica source and titanium oxide (as a titania source).
Ti0z), calcium carbonate (CaCO3) or hydroxylation power AsV as a shear source: (Ca(OF
()z), etc., were weighed so as to have the composition ratios shown in Table 1, wet mixed using a ball mill, dried, and then calcined at 900 to 1100°C for 1 to 2 hours. After calcination, it is finely pulverized to suppress the contamination of impurities, and an organic binder etc. are added, and after granulation it is 1.0 to 2. Pressure molding was performed at Ot/d. Thereafter, it was fired in the air at 1250 to 1380°C to obtain samples &1 to 15 shown in Table 1.

The crystalline phase of the obtained sintered body was identified by X-ray diffraction. The production amount ratio was determined by the beat ratio, and at the same time, the area ratio was measured from the difference in light reflectance of each crystal phase using an XMA device on the mirror surface of the sample using an image analysis device, and evaluated by converting it into a volume ratio. . Note that this value almost coincided with the quantitative ratio determined by X-ray diffraction method. The hardness is determined by the load of 1 kg (E(V
The Vickers hardness is expressed as (1,o). The measurement calculation was based on J Engineering 5Z2244, and the unit was expressed in kg/-. The density of the sintered body is X if the water absorption rate exceeds 2%.
0% is indicated by ○, and the middle is indicated by Δ.

Color unevenness was evaluated by observing the inside of the sintered body after treatment in a reducing atmosphere and determining whether there was a difference in color from the surface.

As understood from Table 1, samples &t, s, 9, 10.
Samples Nos. 11 and 13 are outside the composition range of the present invention, and Samples 51 and 8 have a small amount of TiO2, so sintering is not promoted sufficiently. Samples 9 and 1O are yarns with a small amount of Si and Oz, and the side with a large amount of CaO (sample 59) inhibits the densification of the sintered body, and the side with a large amount of TiO2 (sample iFx)
10), color unevenness occurs. samplezffill
is a system with a large amount of TiOz, and it can be seen that a CaTi5iOs phase with a low coefficient of thermal expansion is generated on the side where the addition of 5iOz is relatively large, and the coefficient of thermal expansion is extremely low at 65 x 10-77°C. Sample A13 has a slightly large amount of 5i02i, so 5i02 exists alone, forming a glass phase, and is not sufficiently densified due to the occurrence of grains. Sample A14 is a conventional T10 t-ca.

This is a typical example of a system composition consisting of two phases, CaTiO2 phase and Ti-0x phase, which causes color unevenness and hardness of Mn.
-The hardness of ferrite is 650 kg/-, which is quite large! 1! During surface processing, the Mn-Zn ferrite side is more likely to be selectively polished. Sample 15 is a conventional phostellite porcelain, which has a small coefficient of thermal expansion and is too hard to be applied as a spherite for Mn--Zn ferrite.

On the other hand, Samples &2 to 7 and 12 are within the scope of the present invention, and their thermal expansion coefficients are selected within the range of 105 to 125 x 10 /°C, which is applicable to Mn-Zn ferrite. A dense sintered body with good hardness and sinterability was obtained, and no color unevenness occurred.

Further, sample point 14 and each sample A2 to within the scope of the present invention
Comparing the calcination temperature of No. 7, the conventional TiO2-CaO
It is understood that the temperature is relatively lower than that of yarn.

As mentioned above, the present invention uses 5j-Oz-Ti, 02-Ca
By setting these as O-based in a specific composition ratio, Mn
- It can be applied to a wide range of thermal expansion coefficients of Zn ferrite, the sintered body is sufficiently densified, there are few bores, and it is possible to prevent color unevenness due to reducing atmosphere treatment, and it has excellent mirror finishing properties. A Sufida composition for heads is obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head used in a floppy disk.

Claims (1)

[Claims] (1) A ceramic composition for a magnetic head comprising 22 to 50 mol% of SiO_2, 2 to 30 mol% of TiO_2, and 45 to 57 mol% of CaO.