JPH0775049B2 - Non-fusing glass composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is suitable as a material for filling voids of a magnetic head using ferrite as a magnetic core, and can be fusion-bonded at a relatively low temperature. The present invention relates to a low fusion glass composition.

[Conventional technology]

In a magnetic head, glass is generally filled in a gap formed between cores made of a magnetic material. As this glass, lead glass containing lead as a main component is usually used.

[Problems to be Solved by the Invention]

However, since the conventional glass for filling the magnetic head has a relatively low hardness, the glass portion filled in the gap in the above magnetic head tends to be worn earlier than the core made of the magnetic material. . For this reason, there is a problem that the recording characteristics are gradually deteriorated due to the abrasion of the glass while the magnetic head is used for a long period of time.

Further, the above-mentioned glass for filling has a drawback that it has poor wettability with an alloy such as Sendust.

Further, in the magnetic head using the above-mentioned glass for filling, a precipitate called nucleation is generated at the interface between the glass and sendust, and it becomes impossible to control the gap size with high accuracy.

Furthermore, the conventional glass for filling described above has poor acid resistance and water resistance, and the surface is easily roughened by an acid or the like.

[Means for Solving the Problems]

In order to solve the above problems, the present inventor has conducted extensive studies on the composition of glass for filling magnetic heads and the like, and as a result, a low-melting glass composition having the following composition is an object of the present invention. It has been found to fit well. That is, the low fusion glass composition according to the present invention contains 1 to 3 wt% of SiO ₂ , B ₂
O ₃ 10 to 14 wt%, a PbO 29-54% by weight, the ZnO 8 to 16 wt%, the Al ₂ O ₃ 2 to 6% by weight, the SrO 2.5 to 4 wt%, ZnF
₂ to 0.1 to 0.2% by weight, NaCl to 0.1 to 0.2% by weight, and NaO ₂ to 2
It is characterized by containing ~ 10% by weight.

[Work]

In the above structure, alumina can be preferably used as a raw material for Al ₂ O ₃ . Also, as raw materials for B ₂ O ₃ , H ₃ BO ₃ , PbO
Pb ₃ O ₄ is suitable as a raw material for each.

Although the content of Al ₂ O ₃ is set to 2 to 6% by weight, the hardness tends to increase as the content of Al ₂ O ₃ increases. However,
When the content exceeds 6% by weight, the adverse effect that the fluidity of the glass in the molten state decreases is observed. When the content of Al ₂ O ₃ is less than 2% by weight, it becomes impossible to sufficiently increase the hardness of glass.

The content of PbO was set in the range of 29-54% by weight, but 29% by weight
If it is less than 5, the degree of vitrification is not sufficient, while
If it is contained in excess of weight%, there arises a problem that the hardness of glass decreases.

Further, by setting the content of SiO ₂ to be 1 to 3% by weight as described above, the yield point can be set to about 380 ° C. or lower, and sufficient low fusion property can be obtained.

Furthermore, when the content of B ₂ O ₂ is in the range of 10 to 14% by weight, devitrification during reheating can be prevented and vitrification can be facilitated.

When the ZnO content is 8 to 16% by weight, devitrification during reheating is prevented and vitrification is facilitated as in the above case.

Further, when the SrO content is in the range of 2.5 to 4% by weight as described above, sufficient wettability is obtained for the alloy with Sendust, etc., and almost no nucleation occurs at the interface with Sendust, etc. Will not do. On the other hand, if the SrO content is less than 2.5% by weight, the wettability is insufficient, while the SrO content is 4%.
If it exceeds 5% by weight, vitrification becomes difficult and the low fusion property of the formed glass is lost.

When the content of Na ₂ O exceeds the above range, that is, more than 10% by weight or less than 2% by weight, water resistance, working temperature,
Good results cannot be obtained in terms of the coefficient of thermal expansion.

When ZnF ₂ is contained in an amount of 0.1 to 0.2% by weight, the water resistance of glass,
It has the effect of improving acid resistance. Note that NaCl is added for clarification.

[Embodiment] The following will describe one embodiment of the present invention with reference to FIG. 1 and FIG.

SiO ₂ , B ₂ O ₃ , PbO, ZnO, Al ₂ O ₃ , BaO, Na ₂ O, K ₂ O, ZnF ₂
And NaCl are collected in fixed amounts and placed in a platinum crucible.
By melting and mixing for 1 hour at a temperature of 1500 ° C,
Samples i to iii of three types of low fusion glass compositions were prepared. The composition and characteristics of each of the obtained samples i to iii are shown in the first page of the next page.
Shown in the table.

As shown in FIG. 1, the strength of each of the samples i to iii is such that a thin film made of an alloy such as sendust (not shown) is formed on the opposing surfaces of the cores 1 and 2 made of ferrite, and The left half portion in the figure of the magnetic head 4 formed by bonding via the low fusion glass composition 3 having the composition shown as the samples i to iii is supported by the jigs 5 and 5,
It was determined as the load at the time when a crack was generated at the site of the low fusible glass composition 3 when the load was applied to the point 2a on the right-hand core 2 of the magnetic head 4. As is clear from Table 1, each of the samples i to iii in which the PbO content was adjusted to 29 to 54% by weight has good strength.

Further, the wettability of the low-fusing glass composition 3 is, as shown in FIG. 2, a groove extending in the depth direction on a test piece 6 made of ferrite.
6a is formed in advance, and the low fusion glass composition 3 in a molten state is fused to the groove 6a portion of the test piece 6 to determine the angle formed by the tangent of the glass surface with respect to the horizontal plane, that is, the wetting angle θ. It was performed by measuring. The width B ₁ of the test piece 6 is 2.
2 mm, depth L is 15 mm, height H ₁ is 1 mm, groove 6a width is B ₂
Was 0.6 mm, and the depth H ₂ of the groove 6a was 0.3 mm. The diameter of the low-fusing glass composition 3 before fusion was 0.7 mm. As can be seen from the data in Table 1, Samples i-iii having the compositional range of the present invention show good wettability.

Moreover, when each of the samples i to iii containing BaO was used as the low-fusing glass composition 3, the above-mentioned nucleation hardly occurred. Furthermore, when each of the above samples i to iii to which ZnF ₂ was added was used as the low fusion glass composition 3, the acid resistance to Hcl and the like was significantly improved, and at the same time, the water resistance was also improved.

Further, as is clear from Table 1, since each sample i to iii has a low yield point, fusion treatment was possible even at a low temperature of about 520 ° C.

Moreover, since the low-fusing glass composition 3 has a smaller coefficient of thermal expansion than ferrite, it has few cracks during cooling after permeating into the voids of the magnetic head 4, and good adhesive strength was obtained. .

〔The invention's effect〕

The low fusion glass composition according to the present invention, as described above,
1-3% by weight of SiO ₂ , 10-14% by weight of B ₂ O ₃ and 29-5 of PbO.
4 wt%, ZnO 8-16 wt%, Al ₂ O ₃ 2-6 wt%, SrO
2.5-4% by weight, ZnF ₂ 0.1-0.2% by weight, NaCl 0.1-
It contains 0.2% by weight and ₂ to 10% by weight of Na ₂ O. This makes it possible to produce a glass with a high degree of hardness, good wettability with alloys such as Sendust, less nucleation, acid resistance,
It becomes possible to obtain a glass composition having excellent water resistance, and as a result, it becomes possible to extend the life of the magnetic head.

Further, it is possible to fuse the glass composition at a relatively low temperature, and it is possible to obtain good adhesive strength with less generation of cracks in the glass during cooling after permeation into the void of the magnetic head. Is.

[Brief description of drawings]

1 and 2 show examples of the present invention. FIG. 1 is a schematic front view showing the test conditions for the strength of a low-fusing glass composition, and FIG. 2 is a low-fusing property. It is a schematic perspective view which shows the test conditions of the wettability of a glass composition. Reference numeral 3 is a low-fusing glass composition, and 4 is a magnetic head.

Claims (1)

[Claims] 1. SiO ₂ 1.0 to 3.0% by weight, B ₂ O ₃ 10 to 14% by weight, PbO 29 to 54% by weight, ZnO 8 to 16% by weight, Al ₂ O ₃ 2 to 6% by weight. %, SrO 2.5 to 4.0% by weight, ZnF ₂ 0.1 to 0.2
Wt%, a NaCl 0.1 to 0.2 wt%, low-melting adhesive glass composition characterized by containing NaO ₂ 2 to 10 wt%.