JPH0670925B2 - Substrate material for thin film magnetic head - Google Patents

Description

The present invention relates to a substrate material of a magnetic head incorporated in a floppy disk device or a mood disk device which is a peripheral device of a computer, and more particularly to a non-magnetic substrate for a thin film magnetic head. Is.

[Conventional technology]

As a magnetic head for high-density recording, it has been replaced by a conventional head using ferrite, and a thin film magnetic head has recently been drawing attention.

Here, Al ₂ O ₃ —TiC ceramics is used as the substrate material for the thin film magnetic head. The reason is that it has high hardness and strength compared to other materials, and therefore exhibits high durability against contact start / stop with a metal-based recording medium used for high-density magnetic recording.

[Problems to be Solved by the Invention]

However, since the thin film magnetic head made of Al ₂ O ₃ -TiC ceramics has poor sinterability, the sintering temperature must be as high as 1850 to 1900 ° C to obtain the dense material required for the substrate material. However, there are drawbacks such as inability to meet the demand for miniaturization due to poor machinability.

The present invention has been studied to eliminate such drawbacks, and its technical problem is to provide a substrate material for a thin film magnetic head which is excellent in sinterability and machinability.

[Means for Solving the Problems]

The present invention is configured to remedy the above-mentioned drawbacks, and in a substrate material for a thin film magnetic head, a ceramic material comprising a main component and an additive, wherein the main component is 15 to 60 wt%.
Of TiC and the balance of Al ₂ O ₃ and the additive is 0.1 to 1 wt% in total with respect to the total weight of the ceramic.
Contained at least one metal silicide selected from the group consisting of respective silicides of Ti, Zr, Nb, Ta, Cr, Mo and W, and its sinterability and workability Is an improvement of.

That is, in the present invention, the addition of the metal silicide improves the sinterability, and becomes maximum when the addition amount is 0.1 to 1.0 wt%. This means that the additive promotes densification while suppressing grain growth of the main component, so that the obtained sinterability is excellent in machinability despite the high relative density. Such an effect cannot be obtained when the amount added is less than 0.1 wt%, and when it exceeds 1 wt%, the formation of a liquid layer in the grain boundary layer becomes remarkable during sintering and the sinterability is improved, but the grain size becomes large. At the same time, the grain boundary strength decreases, and both the Pickers hardness Hv and the bending strength F deteriorate, so that the chipping occurrence rate also increases. Regarding the main component, the amount of TiC is 15 wt% with respect to the total of TiC and Al ₂ O _3.
When the Hv is less than 2000 kg / mm ² or less, and when it exceeds 60 wt%, the sinterability is remarkably reduced, so the TiC content of the main component is 15 to 6
0 wt% is desirable.

Hereinafter, the present invention will be described in detail according to examples.

〔Example〕

Al ₂ O ₃ , TiC, TiSi with an average particle size of 0.1-0.5 μm and a purity of 99% or more
_{2, ZrSi 2, NbSi 2,} TaSi 2, CrSi 2, MoSi 2, and each sample of WSi powders raw material ₂ were weighed so as to be the composition ratios shown in Table 1 No. 1 to No. 10. The main components TiC and Al ₂ O ₃ in the table indicate the composition of the main components (wt%), and the amounts of additives are indicated by the weight ratio (wt%) to the total amount of the main components and additives.

Sample Nos. 1 to 5 are application examples of the present invention, and Sample Nos. 5 to 10 are for comparison.

Each sample of No. 1 to No. 10 was weighed as described above and mixed with ethanol as a solvent in a ball mill for 20 to 40 hours. Next, after drying, add an organic binder,
It was pressure-molded into a block of vertical 30 mm × horizontal 30 mm × height 10 mm. Next, at a temperature of 1750 ° C, this block is placed in an Ar stream for 2
Sintered for hours. After sintering, hot isostatic pressing (HIP) treatment was performed under the conditions of a pressure of 1000 kg / cm ² and a temperature of 1650 ° C. for 2 hours using Ar gas as a pressure medium.

The relative density, Vickers hardness Hv, and flexural strength F were measured to evaluate the material properties of the sample obtained through the above steps. Also, after cutting a 5 mm × 5 mm × 20 mm prism from each sample, two adjacent 5 mm × 20 mm faces of this prism are mirror-polished to obtain a chipping number of 2 × 2 μm or more generated in the ridge.
Count using an optical microscope with 1000x magnification
The workability was evaluated by converting into the occurrence rate per cm. Further, the structure was observed to determine the average particle size.

The above results are shown in Table 1 together with the composition values.

From this table, in comparison with the additive-free example of sample No. 6, TiSi ₂ , ZrS
i ₂ , NbSi ₂ , TaSi ₂ , CrSi ₂ , MoSi ₂ , WSi ₂ , 0.1 to 1 wt% of 0.1 to 1 wt% added average particle size 1.2 to 1.1 μm
Relative density of 99.96-99 despite the small grain size of the tissue.
It has a high density of 98%, and the occurrence rates of Hv, F and chipping are improved.

However, when the addition amount is less than 0.1 wt% (Sample No.7,8), no improvement in sinterability is observed, the relative density is only about 90%, the mechanical strength is low, and therefore the chipping occurrence rate is high.

On the other hand, when the addition amount exceeds 1 wt%, the grain growth becomes remarkable but the decrease in Hv and F and the occurrence of chipping are observed to increase, although the sinterability is improved.

[Effects of the Invention] As described above, according to the present invention, a high-density Al ₂ O _3- for a thin-film magnetic head, which has a small grain size structure, is dense, and has excellent machinability
It is now possible to provide TiC ceramics substrate materials.

Claims (1)

[Claims] 1. A ceramic comprising a main component and an additive, wherein the main component comprises 15 to 60 wt% TiC and the balance substantially Al ₂ O _3, and the additive is the ceramic Containing 0.1 to 1 wt% of the total weight, and consisting of at least one metal silicide selected from the group consisting of Ti, Zr, Nb, Ta, Cr, Mo, and W silicides. A substrate material for a thin film magnetic head characterized by: