JPH0744111B2 - 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 hard disk device which is a peripheral device of a computer, and more particularly to a non-magnetic substrate material for a thin film magnetic head. Is.

<Prior Art> Instead of a conventional head using ferrite as a magnetic head for high-density recording, a thin film head has recently been drawing attention.

Here, Al ₂ O ₃ —TiC is used as the substrate material for the thin film 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 substrate material for a thin-film magnetic head made of Al ₂ O ₃ —TiC ceramics has poor flammability, the sintering temperature is required to obtain a dense substrate material. From 1850
There are drawbacks such as the need to use a high temperature of 1900 ° C and the inability to meet the demand for miniaturization due to poor machinability.

The present invention has been carried out in order 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 improve the above-mentioned drawbacks, and in the Al ₂ O ₃ -15 to 60 wt% TiC ceramics which is a substrate material for a thin film magnetic head, the periodic table IVa, V a, VI Group a metal Ti, Zr, Nb,
It is made by adding 0.1 to 1 wt% of silicides such as Ta, Cr, Mo and W, and 0.1 to 1 wt% of AlN and CaO, respectively, and improving its sinterability and workability.

That is, according to the present invention, 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 , 0.1 to 1 wt% of AlN contained in the total weight of the ceramics
And at least one metal selected from the group consisting of 0.1 to 1 wt% of CaO and 0.1 to 1 wt% of each of Ti, Zr, Nb, Ta, Cr, Mo and W silicides. A substrate material for a thin film magnetic head, which is characterized by comprising a silicide, is obtained.

That is, in the present invention, the sinterability is improved by controlling the addition amount of the metal silicide, and particularly when the addition amount is 0.1 to 1 wt%, the density of the sintered body becomes maximum. At this time, since the metal silicide promotes the densification while suppressing the grain growth of the main component, the sintered body obtained is excellent in machinability even though the relative density is high. This kind of effect is 0.1w
If it is less than t%, it cannot be obtained, and if it exceeds 1 wt%, the liquid phase is remarkably generated in the grain boundary layer during sintering and the sinterability is improved, but the grain size is increased and at the same time the grain boundary strength is decreased and Mechanical strength deteriorates.

On the other hand, with regard to the addition of AlN and CaO, improvement in sinterability and, at the same time, improvement in machinability are observed, and the maximum is obtained when the addition amounts of AlN and CaO are each 0.1 to 1 wt%. It is known that AlN and CaO form a liquid phase, and it is considered that liquid phase sintering proceeds by simultaneous addition of AlN and CaO. Further, since AlN has a relatively high machinability and a relatively high machinability despite its high hardness, the obtained sintered body has a high strength and an excellent machinability. Such an effect can be obtained only when AlN and CaO are added at the same time.
If it is less than 1 wt%, the effect is insufficient, while if it exceeds 1 wt%,
AlN becomes difficult to sinter, which causes a decrease in sinterability.

Furthermore, regarding the main component, TiC relative to the total of TiC and Al ₂ O ₃
If the amount is less than 15 wt%, Hv will be 2000 kg / mm ² or less.
If the content exceeds wt%, the sinterability will decrease significantly, so the main component Ti
The amount of C is preferably 15-60 wt%.

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

<Example> Al ₂ O ₃ , TiC, TiSi having an average particle size of 0.1 to 0.5 μm and a purity of 99% or more
_{2, ZrSi 2, NbSi 2,} TaSi 2, CrSi 2, MoSi 2, WSi 2, AlN, were weighed so as to be the composition ratios shown each powder raw material of CaCO ₃ in Table 1 No.1~
There were 10 samples. In the table, the main components TiC and Al ₂ O ₃ indicate the composition ratio (wt%) of the main components, and the amounts of additives are indicated by the weight ratio (wt%) to the total amount of the main components. Note that CaCO ₃ is a value converted to CaO.

Sample Nos. 1 to 5 are application examples of the present invention, and Nos. 6 to 10 are for comparison.

Each sample of Nos. 1 to 10 was weighed as described above and mixed with ethanol as a solvent in a ball mill for 20 to 40 hours. Next, after filtering and drying, add an organic binder and add 30 x 30 x 10 mm.
Was molded into blocks. Then this block 1750
After sintering at ℃ for 2 hours in Ar flow, Ar gas was used as a pressure medium, and hot isostatic pressing (HIP) treatment was performed under the conditions of pressure 1000 kg / cm ² temperature 1650 ℃ 2 hours holding.

The relative density Vickers hardness Hv and the bending strength F were measured to evaluate the material properties of the samples obtained through the above steps. Also, after cutting out a 5 × 5 × 20 mm prism from each sample, two adjacent 5 × 20 mm surfaces of this prism are mirror-polished and the chipping number of 2 × 2 μm or more generated at the ridge has a magnification of 1000 times. It was counted using a microscope and converted into an occurrence rate per cm to evaluate workability. 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, ZrSi 2, NbSi 2} , TaSi 2, CrSi 2, MoSi 2, at least one of 0.1 to 1 wt% of WSi _2, 0.1 to 1 wt% each of AlN and CaO
In the added sample, the relative density is as high as 99.96 to 99.98% despite the fact that the average particle size is 1.1 to 1.2 μm and the particle size is small.
Moreover, the Hv, F, and chipping occurrence rates are all improved.

In addition, in the case of adding only metal silicide (No.7), the density, composition, mechanical strength and workability are all improved compared to the additive-free additive (No.6). further
Both the F and chipping occurrence rates are somewhat inferior to those of the present invention examples (Nos. 1 to 5) in which AlN and CaO were added simultaneously.

Sample No. 8 has only AlN and CaO added, and has better sinterability than the non-added example, but the relative density is 95%.
The degree is low.

When the amount of metal silicide added exceeds 1 wt% (No.9), sinterability is improved, but grain growth becomes remarkable, and Hv, F decrease and chipping incidence increase.

On the other hand, if the amount of AlN added exceeds 1 wt% (No. 10), the sinterability of AlN appears and the sinterability decreases.

<Effects of the Invention> As described above, according to the present invention, there is provided a high-density Al ₂ O ₃ —TiC ceramics substrate material for a thin film magnetic head, which is excellent in sinterability, has a small grain size structure, is dense, and is excellent in machinability. Became possible.

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. 0.1 to 1 wt% of AlN and 0.1 to 1 wt% of CaO based on the total weight of
And at least one metal silicide selected from the group consisting of respective silicides of Ti, Zr, Nb, Ta, Cr, Mo, and W contained in a total amount of 0.1 to 1 wt%. Substrate material for thin film magnetic heads.